Plant Cells and their Organelles · Plant Golgi introduction, 66 Structure and organization, 69...
Transcript of Plant Cells and their Organelles · Plant Golgi introduction, 66 Structure and organization, 69...
Plant Cells and their Organelles
Plant Cells and their OrganellesEditEd By
William V Dashek
and
Gurbachan S Miglani
This edition first published 2017 copy 2017 by John Wiley amp Sons Ltd
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Library of Congress Cataloging‐in‐Publication Data
Names Dashek William V editor | Miglani Gurbachan S editorTitle Plant cells and their organelles by William V Dashek Gurbachan S MiglaniDescription [Hoboken NJ] Wiley 2017 | Includes bibliographical references and indexIdentifiers LCCN 2016024724 (print) | LCCN 2016026083 (ebook) | ISBN 9780470976869 (cloth) |
ISBN 9781118924761 (pdf) | ISBN 9781118924754 (epub)Subjects LCSH Plant cells and tissuesndashTextbooksClassification LCC QK725 D36 2017 (print) | LCC QK725 (ebook) | DDC 5813ndashdc23LC record available at httpslccnlocgov2016024724
A catalogue record for this book is available from the British Library
Wiley also publishes its books in a variety of electronic formats Some content that appears in print may not be available in electronic books
Cover image copy Alan John Lander PhillipsGettyimages
Set in 9513pt Meridien by SPi Global Pondicherry India
1 2017
v
Contributors ix
Preface xi
Acknowledgments xii
1 An introduction to cells and their organelles 1
William V Dashek
Cells 1
Cell organelles ndash an introduction 6
Ion channels 10
Proton pumps 14
Water channels 14
Carriers 15
Cell death 17
References 18
Further reading 24
2 Isolation and characterization of subcellular organelles from plant cells 25
Milee Agarwal P Desai and Harish Padh
Isolation of subcellular organelles 26
Identification and characterization of isolated organelles 33
Summary 39
References 39
Further reading 41
3 Endoplasmic reticulum 42
William V Dashek
Structure 42
Chemical composition 42
Biogenesis 45
Functions 45
Posttranslational events 49
Inhibitors 53
In vitro protein synthesis 54
Other functions 54
References 54
Further reading 60
Contents
vi Contents
4 The Golgi apparatus 61
D Davis TE Wilkop and Georgia Drakakaki
The Golgi apparatus 61
Plant Golgi introduction 66
Structure and organization 69
Golgi‐mediated vesicular trafficking 71
Plant Golgi‐dependent cellular processes 74
Imaging and visualization 76
Isolation and analysis 78
Golgi genetics and genomics 81
Significance 84
Acknowledgment 85
References 85
Further reading 87
5 Microbodies 88
Robert Donaldson
Introducing peroxisomes 88
Leaf peroxisomes 89
Peroxisomes in oil seeds and pollen 91
References 107
Further reading 109
6 Microtubules intermediate filaments and actin filaments 110
William V Dashek
Microtubules 110
Intermediate filaments 113
Actin filaments (microfilaments) 116
References 119
Further reading 124
7 The mitochondrion 125
Ray J Rose Terence W‐Y Tiew and William V Dashek
Structure and dynamics 125
The mitochondrial genome 128
Comparison of the mitochondrial genome with chloroplast and nuclear
genomes 131
The mitochondrial proteome and protein import 132
Respiratory metabolite transporters 133
The electron transport chain and oxidative phosphorylation 133
The alternative electron transfer chain in plant mitochondria 139
Plant mitochondria stress responses and programmed cell death 139
Other functions of plant mitochondria 140
References 144
Further reading 145
Contents vii
8 Nucleus 146
Yogesh Vikal and Dasmeet Kaur
Structural organization of the NE 147
Nuclear pores 152
The nucleolus 157
Chromatin and chromosomes 165
DNA structure 170
DNA replication 173
RNA structure function and synthesis 176
Nucleocytoplasmic transport nuclear import and nuclear export 183
The dynamics of NE biogenesis during mitosis 188
The dynamics of nuclear pore complex biogenesis 196
Cell cycle control 200
Summary 205
References 206
Further reading 207
9 Plant cell walls 209
James E Bidlack and William V Dashek
Introduction 209
Structure 209
Biosynthesis 216
Chemical composition 217
Biogenesis 222
Function 225
References 231
Further reading 238
10 Plastid structure and genomics 239
Gurbachan S Miglani
Plastid structure 239
Different forms of plastids 240
Plastid stromules 248
Chlorophyll biosynthesis 248
Plastid genomics 250
Sequenced plastomes 253
Promiscuous DNA 258
Plastid genome organization 260
Plastid gene organization expression and regulation 265
Systems biology approach in understanding chloroplast development 269
Chloroplast genetic engineering 284
Recent trends in chloroplast research 289
Summary 293
References 294
Further reading 299
viii Contents
11 Photosynthesis 300
J Kenneth Hoober
Introduction 300
Evolution of photosynthesis 301
Development of the chloroplast 310
Absorption of light energy 317
Generation of end products 324
Distribution of the photosystems in thylakoid membranes 329
Photoinhibition damage and repair of the PS II reaction center 332
Protection of PS II by carotenoids 332
Incorporation of carbon as CO2 into carbohydrate 334
End products of carbon assimilation 346
Conclusions for the reactions of photosynthesis 348
References 348
Further reading 350
12 Vacuoles and protein bodies 351
William V Dashek and Amy M Clore
Vacuoles 351
PBs and other protein storage compartments 359
References 365
Further reading 370
13 Systems biology in plant cells and their organelles 371
Rajdeep Kaur Grewal Saptarshi Sinha and Soumen Roy
Systems biologymdashldquoomicsrdquo 371
Genomics 373
Lipidomics 378
Metabolomics 380
Proteomics 382
Transcriptomics 384
Synthetic biology 386
Acknowledgments 388
References 389
Further reading 391
Appendix A 392
Appendix B 400
Appendix C 403
Index 407
ix
Milee AgarwalScientist
Pharmacology and Toxicology Department
BV Patel PERD Centre
Ahmedabad Gujarat India
James E BidlackProfessor of Biology and CURE‐STEM
Scholar
Department of Biology
University of Central Oklahoma
Edmond OK USA
Amy M CloreProfessor of Biology
Division of Natural Sciences
New College of Florida
Sarasota FL USA
William V DashekRetired Faculty
Adult Degree Program
Mary Baldwin College
Staunton VA USA
D DavisGraduate Student
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
P DesaiScientist
Cellular and Molecular Biology Department
BV Patel PERD Centre
Ahmedabad Gujarat India
Robert DonaldsonProfessor
Department of Biological Sciences
George Washington University
Washington DC USA
Georgia DrakakakiAssociate Professor
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
Rajdeep Kaur GrewalSenior Research Fellow
Department of Physics
Bose Institute
Kolkata India
J Kenneth HooberProfessor Emeritus
School of Life Sciences
Center for Photosynthesis
Arizona State University
Tempe AZ USA
Dasmeet KaurResearch Assistant
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
Gurbachan S MiglaniVisiting Professor
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
Contributors
x Contributors
Harish PadhVice-Chancellor
Sardar Patel University
Vallabh Vidyanagar Anand
Gujarat India
Ray J RoseEmeritus Professor
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Soumen RoyAssociate Professor
Department of Physics
Bose Institute
Kolkata India
Saptarshi SinhaSenior Research Fellow
Department of Physics
Bose Institute
Kolkata India
Terence W‐Y TiewGraduate Student
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Yogesh VikalSenior Geneticist
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
TE WilkopSenior Project Scientist
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
xi
Plant Cells and their Organelles is an advanced textbook to enhance the plant
biology studentrsquos knowledge of the structure and function of plant cells and their
organelles The book assumes that the student has had introductory courses in
plant science and chemistry The book emphasizes the research literature in
plant cell biology concerning cell and organellar structure However the litera-
ture from plant physiology molecular genetics and biochemistry has been
utilized to augment the discussions of cell and organellar function
Preface
xii
Dashek is grateful to Drs WG Rosen WF Millington and DTA Lamport for
training enabling a career in teaching and research in plant biology Dashek
appreciates the grant support of the USArsquos NIH NSF DOE and USDA Forest
Service Dashek thanks Ms Katherine Mumford Ms Retha Howard and
Ms Abigail M Johnson for technical assistance in the preparation of the
manuscript
Miglani wishes to record his appreciation for Dr Darshan S Brar Honorary
Adjunct Professor School of Agricultural Biotechnology Punjab Agricultural
University Ludhiana India for his valuable technical suggestions Miglani
thanks Dr (Mrs) Parveen Chhuneja Director School of Agricultural
Biotechnology Punjab Agricultural University Ludhiana India for motivat-
ing me to prepare this volume and the Punjab Agricultural University for
providing facilities for this work
We thank the Wiley editorial staff members for their attention to detail
Acknowledgments
1
Plant Cells and their Organelles First Edition Edited by William V Dashek and Gurbachan S Miglani
copy 2017 John Wiley amp Sons Ltd Published 2017 by John Wiley amp Sons Ltd
Cells
Parenchyma chlorenchyma collenchyma and sclerenchyma are the four main
plant cell types (Figure 11 Evert 2006) Meristematic cells which occur in
shoot and root meristems are parenchyma cells Chlorenchyma cells contain
chloroplasts and lack the cell wall thickening layers of collenchyma and scleren-
chyma Certain epidermal cells can be specialized as stomata that are important
in gas exchange (Bergmann and Sack 2007) The diverse cell types (Zhang et al
2001 Yang and Liu 2007) are shown in Table 11 Photomicrographs of certain of
these cell types can be found in Evert (2006) Fahn (1990) Beck (2005) Rudall
(2007) Gunning (2009) MacAdam (2009) Wayne (2009) Beck (2009) Assmann
and Liu (2014) and Noguchi et al (2014)
How do cells ariseCells arise by cell divisions (see Chapter 8 for mitosis and meiosis) in shoot and
root (Figures 12 and 13) meristems (Table 12 Lyndon 1998 McManus and Veit
2001 Murray 2012) The shoot apex is characterized by a tunicandashcorpus organiza-
tion (Steeves and Sussex 1989) The tunica gives rise to the protoderm and its
derivative the epidermis In contrast the corpus provides the procambium which
yields the primary xylem and phloem In addition the ground tissue derives from
the corpus originating the pith and cortex Following divisions cells can differenti-
ate into tissues (Table 13) and organs of the mature plant body (Leyser and Day
2003 Sachs 2005 Dashek and Harrison 2006) The leaf primodium arises on the
apex (Micol and Hake 2003) The mature angiosperm leaf consists of palisade cells
and spongy mesophyll cells sandwiched between the upper and the lower epider-
mis (Figure 14) The epidermis possesses guard cells with associated stomata that
function in gas exchange KNOX genes affect meristem maintenance and suitable
patterning of organ formation (Hake et al 2004) In dissected leaves KNOX genes
are expressed in leaf primordia (Hake et al 2004) Hake et al (2004) suggest that
An introduction to cells and their organellesWilliam V DashekRetired Faculty Adult Degree Program Mary Baldwin College Staunton VA USA
CHapter 1
2 Plant cells and their organelles
KNOX genes may be important in the diversity of leaf form Extensive discussions
of leaf development occur in Sinha (1999) Micol and Hake (2003) and Efroni
et al (2010) Under appropriate stimuli the vegetative apex can be converted to a
floral apex (Figure 15) Photoperiod (Mazumdar 2013) such as short days and
long days and combinations of the two is one such stimulus (Glover 2007
Kinmonth‐Schultz et al 2013) This induction results in the production of florigen
(Turck et al 2008) the flowering hormone (Zeevaart 2006) While early reports
suggest that florigen is an mRNA species (Huang et al 2005) a more recent inves-
tigation indicates that florigen is a protein complex (Yang et al 2007 Taoka et al
2013) Taoka et al state that florigen protein is encoded by the gene Flowering
Locus T in Arabidopsis species (Shresth et al 2014) It is believed that florigen is
induced in leaves and that it moves through the phloem to the shoot apex Plant
hormones (see Appendix A) can influence floral development (Howell 1998)
Gibberellins (Blaacutezquez et al 1998) auxins and jasmonic acid can affect petal
development In contrast auxin can influence gynoecium development The ABC
model has been proposed for regulating the development of floral parts (Soltis
et al 2006) The A gene expression is responsible for sepals while the petals are
the result of co‐expression of A and B genes The B and C genes are responsible for
stamen development and carpels require C genes In certain plants vernalization
(low temperature) can induce flowering in certain plants (Kemi et al 2013)
A diagram of the mature angiosperm plant body is presented in Figure 16 Plant
Primary phloem bres
CO
par
A
Epidermis
Cortex
Phloem
Vascularcambium
Secondaryxylem
Figure 11 Plant cell types Left parenchyma (par) and collenchyma (co) Right
sclerenchyma Source Evert (2006) Reproduced with permission of John Wiley amp Sons
Tab
le 1
1 P
lan
t ce
ll t
ypes
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Epid
erm
al c
ells
Uns
peci
aliz
ed c
ells
one
laye
r of
cel
ls in
thi
ckne
ss o
uter
cov
erin
g of
var
ious
pla
nt p
arts
varia
ble
in s
hape
but
oft
en t
abul
ar
Ever
t (2
006)
Ex
ampl
es
G
uard
cel
lsSp
ecia
lized
epi
derm
al c
ells
cre
scen
t sh
aped
con
tain
chl
orop
last
s f
orm
def
ines
sto
mat
al p
ore
Will
e an
d Lu
cas
(198
4)
Su
bsid
iary
cel
lsC
ells
whi
ch s
ubte
nd t
he s
tom
atal
gua
rd c
ells
http
an
ubis
ru
acz
aM
ain
AN
ATO
MY
gua
rdce
llsh
tml
Tr
icho
mes
An
outg
row
th o
f an
epi
derm
al c
ell
can
be u
nice
llula
r or
mul
ticel
lula
rC
allo
w (2
000)
Pare
nchy
ma
cells
Isod
iam
etric
thi
n‐w
alle
d pr
imar
y ce
ll w
all
in s
ome
inst
ance
s m
ay h
ave
seco
ndar
y w
alls
not
high
ly d
iffer
entia
ted
fun
ctio
n in
pho
tosy
nthe
sis
sec
retio
n o
rgan
ic n
utrie
nt a
nd w
ater
stor
age
reg
ener
atio
n in
wou
nd h
ealin
g
Ever
t (2
006)
and
Saj
eva
and
Mau
seth
(199
1)
Ex
ampl
es
Tr
ansf
er c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
lasm
alem
ma
grea
tly e
xpan
ded
irre
gula
r ex
tens
ions
of
cell
wal
l int
o pr
otop
lasm
tra
nsfe
r di
ssol
ved
subs
tanc
es b
etw
een
adja
cent
cel
l oc
cur
in p
ith
and
cort
ex o
f st
ems
and
root
s p
hoto
synt
hetic
tis
sues
of
leav
es f
lesh
of
succ
ulen
t fr
uits
endo
sper
m o
f se
eds
Das
hek
et a
l (1
971)
and
Off
ler
et a
l
(200
3)
Col
lenc
hym
a ce
llsLa
mel
lar
or p
late
col
lenc
hym
a w
ith t
hick
enin
gs o
n th
e ta
ngen
tial w
alls
Ang
ular
col
lenc
hym
a w
ith t
hick
enin
gs a
roun
d th
e ce
ll w
alls
Pres
ent
in a
eria
l por
tions
of
the
plan
t bo
dy
Vasc
ular
cel
lsEv
ert
(200
6)
Ph
loem
Siev
e ce
lls
Siev
e el
emen
ts
Com
pani
on c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
osse
ss n
umer
ous
plas
mod
esm
atal
con
nect
ions
Opa
rka
and
Turg
eon
(199
9)
Alb
umin
ous
cells
in
gym
nosp
erm
s
Abs
ence
of
star
ch c
ytop
lasm
ic b
ridge
s w
ith s
ieve
cel
ls d
ense
pro
topl
asm
abu
ndan
ce o
f
poly
som
es h
ighl
y co
nden
sed
euch
rom
atin
and
abu
ndan
t m
itoch
ondr
ia
Alo
si a
nd A
lfier
i (19
72) a
nd
Saut
er e
t al
(19
76)
X
ylem
Trac
heid
s
Vess
els
Long
tap
erin
g ce
ll w
ith li
gnifi
ed s
econ
dary
wal
l thi
cken
ings
can
hav
e pi
ts in
wal
ls d
evoi
d of
prot
opla
sm a
t m
atur
ity n
ot a
s sp
ecia
lized
as
vess
els
wid
espr
ead
Tyre
e an
d Zi
mm
erm
an (2
002)
Fuku
da (2
004)
and
Eve
rt (2
006)
(Con
tinue
d )
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Spec
ializ
ed c
ells
ndash H
ydat
hode
s
(mod
ified
par
ts o
f le
aves
and
leaf
tip
s or
mar
gins
)
Con
sist
of
term
inal
tra
chei
ds e
pith
em t
hin‐
wal
led
chlo
ropl
ast‐
defic
ient
cel
ls a
she
ath
with
wat
er p
ores
gut
tatio
n di
scha
rge
of li
quid
con
tain
ing
vario
us d
isso
lved
sol
utes
fro
m a
leaf
rsquos
inte
rior
Lers
ten
and
Cur
tis (1
996)
http
sw
ww
bio
sciu
texa
sed
u a
nd
Mae
da a
nd M
aeda
(198
8)
Latic
ifer
cells
Cel
ls o
r a
serie
s of
cel
ls w
hich
pro
duce
late
xFa
hn (1
990)
Pic
kard
(200
8) a
nd
Botw
ebu
wsp
Edu
Si
mpl
eSi
ngle
-cel
led
C
ompo
und
and
artic
ulat
ed
Uni
on o
f ce
lls c
ompo
und
in o
rigin
and
con
sist
of
long
itudi
nal c
hain
s of
cel
ls w
all s
epar
atin
g
cells
rem
ain
inta
ct c
an b
ecom
e pe
rfor
ated
or
entir
ely
rem
oved
Salt
glan
dsM
odifi
ed t
richo
mes
tw
o‐ce
lled
and
posi
tione
d fla
t on
the
sur
face
in r
ows
para
llel t
o th
e le
af
surf
ace
occ
ur in
Poa
ceae
Ever
t (2
006)
Tan
et
al (
2010
) O
ross
et a
l (1
985)
and
Tho
mso
n et
al
(198
8)
Cap
cel
l ndash la
rge
nucl
eus
and
expa
nded
cut
icle
Nai
doo
and
Nai
doo
(199
8)
Basa
l cel
l ndash n
umer
ous
and
larg
e ex
tens
ive
part
ition
ing
inva
gina
tions
of
plas
mal
emm
a
Nec
tarie
sFo
und
in n
ecta
rines
pro
duce
nec
tar
usua
lly a
t th
e ba
se o
f a
flow
erFa
hn (1
990)
Nic
olso
n an
d N
epi (
2005
)
and
Paiv
a (2
009)
Idio
blas
tsC
ryst
al‐c
onta
inin
g ce
llsLe
rste
n an
d H
orne
r (2
005)
Ex
ampl
e
Ra
phid
esPr
oduc
e ne
edle
‐sha
ped
crys
tals
Muc
ilage
cel
lO
ccur
in a
larg
e nu
mbe
r of
dic
ots
com
mon
in c
erta
in c
acti
slim
y m
ucila
ge p
reve
nts
evap
orat
ion
of w
ater
by
bind
ing
to w
ater
a p
aren
chym
a ce
ll w
hose
dic
tyos
omes
pro
duce
muc
ilage
as
in s
eed
coat
s c
ell w
alls
are
cel
lulo
sic
and
unlig
nifie
d
http
w
ww
sbs
ute
xas
edu
mas
uetl
web
lab
web
chap
9sec
reto
ry9
1‐2
htm
l
Wes
tern
et
al (
2000
) and
Ars
ovsk
ia
et a
l (2
010)
Oil
cells
Spec
ializ
ed c
ells
app
ear
like
larg
e pa
renc
hym
a ce
lls c
an o
ccur
in v
ascu
lar
and
grou
nd t
issu
es
of s
tem
and
leaf
cel
l wal
l has
thr
ee d
istin
ct la
yers
cav
ity is
for
med
aft
er t
he in
ner
wal
l lay
er
has
been
dep
osite
d
Rode
las
et a
l (2
008)
htt
pbr
ittan
ica
com
and
Ler
sten
et
al (
2006
)
Dru
ses
Sphe
rical
agg
rega
tes
of p
rism
atic
cry
stal
sLe
rste
n an
d H
orne
r (2
005)
Cel
ls in
non
‐ang
iosp
erm
s
Br
yoph
ytes
Gem
mae
One
to
man
y ce
llsht
tp
build
ingt
hepr
ide
com
fac
ulty
pgda
viso
nbr
yolo
gy_l
inks
htm
Hyd
roid
sW
ater
‐con
duct
ing
cells
http
w
ww
Bio
logy
‐onl
ine
org
Lept
oids
ndash P
terid
ophy
tes
Org
anic
com
poun
d‐co
nduc
ting
cells
spo
roge
nous
cel
ls p
rese
nt in
spo
rang
ia o
f so
ri
Tab
le 1
1 (
Con
tin
ued
)
An introduction to cells and their organelles 5
development is discussed in Fosket (1999) Moore and Clark (1995) Greenland
(2003) Leyser and Day (2003) and Rudall (2007)
What is the composition of cellsCertain plant components exhibit polar growth for example the tip growth of
pollen tubes (Hepler et al 2001) The tubes elongate via the fusion of Golgi‐
derived vesicles with the plasmalemma and subsequent deposition of the vesi-
clesrsquo contents into the cell wall (Taylor and Hepler 1997 Parton et al 2001 and
others as reviewed in Malho (2006a 2006b)) In 2007 Dalgic and Dane (2005)
published a diagram depicting the now known tube‐tip structural elements and
physiological processes that facilitate tube elongation The diagram represents a
Figure 12 Angiosperm shoot meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
Figure 13 Angiosperm root meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
6 Plant cells and their organelles
significant advance over the early studies of pollen tubes as it assigns function to
ultrastructural components for example signalling molecules the Rho family of
GTPases and phosphatidylinositol 45 bisphosphate appear to be localized in the
apical plasma membrane Besides pollen tubes root hairs exhibit polar growth
Cell organelles ndash an introduction
Organelles are required for plant growth development and function (Sadava
1993 Gillham 1994 Herrmann 1994 Agrawal 2011) These organelles
(Figure 17) are the loci for a myriad of physiological and biochemical processes
(Tobin 1992 Daniell and Chase 2004 ndash see individual chapters)
There are many diagrams of a generalized plant cell Some of these are available
at wwwexplorebiologycom httpwwwdaviddarlinginfoimagesplant_celljpg
Table 12 Meristems and their derivatives
Meristems Derivatives
Primary
Protoderm Epidermis
From tunica (Evert 2006)
Procambium (provascular) Primary xylem and phloem
From corpus (Evert 2006) Vascular cambium
Ground Ground tissue pith and cortex
Lateral
Vascular cambium
Fusiform initials Secondary xylem
Secondary phloem
Ray initials (Evert 2006) Ray cells
Cork cambium
Phellogen Replaces the epidermis when cork cambium initiates stem girth
increase composed of lsquoboxlikersquo cork cells which are dead at
maturity protoplasm secretes suberin some cork cells that are
loosely packed give rise to lenticels which function in gas exchange
between the air and the stemrsquos interior httpwwwBiology‐online
org Evert (2006) httpwwwvebrioSceincevunlenvirut
Periderm (Evert 2006)
Phelloderm Parenchyma cells produced on the inside by the cork cambium
Meristems are discussed by Steeves and Sussex (1989)
Table 13 Plant tissues
Tissue system
Meristematic Ground Vascular Dermal
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
Plant Cells and their OrganellesEditEd By
William V Dashek
and
Gurbachan S Miglani
This edition first published 2017 copy 2017 by John Wiley amp Sons Ltd
Registered OfficeJohn Wiley amp Sons Ltd The Atrium Southern Gate Chichester West Sussex PO19 8SQ UK
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Library of Congress Cataloging‐in‐Publication Data
Names Dashek William V editor | Miglani Gurbachan S editorTitle Plant cells and their organelles by William V Dashek Gurbachan S MiglaniDescription [Hoboken NJ] Wiley 2017 | Includes bibliographical references and indexIdentifiers LCCN 2016024724 (print) | LCCN 2016026083 (ebook) | ISBN 9780470976869 (cloth) |
ISBN 9781118924761 (pdf) | ISBN 9781118924754 (epub)Subjects LCSH Plant cells and tissuesndashTextbooksClassification LCC QK725 D36 2017 (print) | LCC QK725 (ebook) | DDC 5813ndashdc23LC record available at httpslccnlocgov2016024724
A catalogue record for this book is available from the British Library
Wiley also publishes its books in a variety of electronic formats Some content that appears in print may not be available in electronic books
Cover image copy Alan John Lander PhillipsGettyimages
Set in 9513pt Meridien by SPi Global Pondicherry India
1 2017
v
Contributors ix
Preface xi
Acknowledgments xii
1 An introduction to cells and their organelles 1
William V Dashek
Cells 1
Cell organelles ndash an introduction 6
Ion channels 10
Proton pumps 14
Water channels 14
Carriers 15
Cell death 17
References 18
Further reading 24
2 Isolation and characterization of subcellular organelles from plant cells 25
Milee Agarwal P Desai and Harish Padh
Isolation of subcellular organelles 26
Identification and characterization of isolated organelles 33
Summary 39
References 39
Further reading 41
3 Endoplasmic reticulum 42
William V Dashek
Structure 42
Chemical composition 42
Biogenesis 45
Functions 45
Posttranslational events 49
Inhibitors 53
In vitro protein synthesis 54
Other functions 54
References 54
Further reading 60
Contents
vi Contents
4 The Golgi apparatus 61
D Davis TE Wilkop and Georgia Drakakaki
The Golgi apparatus 61
Plant Golgi introduction 66
Structure and organization 69
Golgi‐mediated vesicular trafficking 71
Plant Golgi‐dependent cellular processes 74
Imaging and visualization 76
Isolation and analysis 78
Golgi genetics and genomics 81
Significance 84
Acknowledgment 85
References 85
Further reading 87
5 Microbodies 88
Robert Donaldson
Introducing peroxisomes 88
Leaf peroxisomes 89
Peroxisomes in oil seeds and pollen 91
References 107
Further reading 109
6 Microtubules intermediate filaments and actin filaments 110
William V Dashek
Microtubules 110
Intermediate filaments 113
Actin filaments (microfilaments) 116
References 119
Further reading 124
7 The mitochondrion 125
Ray J Rose Terence W‐Y Tiew and William V Dashek
Structure and dynamics 125
The mitochondrial genome 128
Comparison of the mitochondrial genome with chloroplast and nuclear
genomes 131
The mitochondrial proteome and protein import 132
Respiratory metabolite transporters 133
The electron transport chain and oxidative phosphorylation 133
The alternative electron transfer chain in plant mitochondria 139
Plant mitochondria stress responses and programmed cell death 139
Other functions of plant mitochondria 140
References 144
Further reading 145
Contents vii
8 Nucleus 146
Yogesh Vikal and Dasmeet Kaur
Structural organization of the NE 147
Nuclear pores 152
The nucleolus 157
Chromatin and chromosomes 165
DNA structure 170
DNA replication 173
RNA structure function and synthesis 176
Nucleocytoplasmic transport nuclear import and nuclear export 183
The dynamics of NE biogenesis during mitosis 188
The dynamics of nuclear pore complex biogenesis 196
Cell cycle control 200
Summary 205
References 206
Further reading 207
9 Plant cell walls 209
James E Bidlack and William V Dashek
Introduction 209
Structure 209
Biosynthesis 216
Chemical composition 217
Biogenesis 222
Function 225
References 231
Further reading 238
10 Plastid structure and genomics 239
Gurbachan S Miglani
Plastid structure 239
Different forms of plastids 240
Plastid stromules 248
Chlorophyll biosynthesis 248
Plastid genomics 250
Sequenced plastomes 253
Promiscuous DNA 258
Plastid genome organization 260
Plastid gene organization expression and regulation 265
Systems biology approach in understanding chloroplast development 269
Chloroplast genetic engineering 284
Recent trends in chloroplast research 289
Summary 293
References 294
Further reading 299
viii Contents
11 Photosynthesis 300
J Kenneth Hoober
Introduction 300
Evolution of photosynthesis 301
Development of the chloroplast 310
Absorption of light energy 317
Generation of end products 324
Distribution of the photosystems in thylakoid membranes 329
Photoinhibition damage and repair of the PS II reaction center 332
Protection of PS II by carotenoids 332
Incorporation of carbon as CO2 into carbohydrate 334
End products of carbon assimilation 346
Conclusions for the reactions of photosynthesis 348
References 348
Further reading 350
12 Vacuoles and protein bodies 351
William V Dashek and Amy M Clore
Vacuoles 351
PBs and other protein storage compartments 359
References 365
Further reading 370
13 Systems biology in plant cells and their organelles 371
Rajdeep Kaur Grewal Saptarshi Sinha and Soumen Roy
Systems biologymdashldquoomicsrdquo 371
Genomics 373
Lipidomics 378
Metabolomics 380
Proteomics 382
Transcriptomics 384
Synthetic biology 386
Acknowledgments 388
References 389
Further reading 391
Appendix A 392
Appendix B 400
Appendix C 403
Index 407
ix
Milee AgarwalScientist
Pharmacology and Toxicology Department
BV Patel PERD Centre
Ahmedabad Gujarat India
James E BidlackProfessor of Biology and CURE‐STEM
Scholar
Department of Biology
University of Central Oklahoma
Edmond OK USA
Amy M CloreProfessor of Biology
Division of Natural Sciences
New College of Florida
Sarasota FL USA
William V DashekRetired Faculty
Adult Degree Program
Mary Baldwin College
Staunton VA USA
D DavisGraduate Student
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
P DesaiScientist
Cellular and Molecular Biology Department
BV Patel PERD Centre
Ahmedabad Gujarat India
Robert DonaldsonProfessor
Department of Biological Sciences
George Washington University
Washington DC USA
Georgia DrakakakiAssociate Professor
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
Rajdeep Kaur GrewalSenior Research Fellow
Department of Physics
Bose Institute
Kolkata India
J Kenneth HooberProfessor Emeritus
School of Life Sciences
Center for Photosynthesis
Arizona State University
Tempe AZ USA
Dasmeet KaurResearch Assistant
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
Gurbachan S MiglaniVisiting Professor
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
Contributors
x Contributors
Harish PadhVice-Chancellor
Sardar Patel University
Vallabh Vidyanagar Anand
Gujarat India
Ray J RoseEmeritus Professor
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Soumen RoyAssociate Professor
Department of Physics
Bose Institute
Kolkata India
Saptarshi SinhaSenior Research Fellow
Department of Physics
Bose Institute
Kolkata India
Terence W‐Y TiewGraduate Student
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Yogesh VikalSenior Geneticist
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
TE WilkopSenior Project Scientist
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
xi
Plant Cells and their Organelles is an advanced textbook to enhance the plant
biology studentrsquos knowledge of the structure and function of plant cells and their
organelles The book assumes that the student has had introductory courses in
plant science and chemistry The book emphasizes the research literature in
plant cell biology concerning cell and organellar structure However the litera-
ture from plant physiology molecular genetics and biochemistry has been
utilized to augment the discussions of cell and organellar function
Preface
xii
Dashek is grateful to Drs WG Rosen WF Millington and DTA Lamport for
training enabling a career in teaching and research in plant biology Dashek
appreciates the grant support of the USArsquos NIH NSF DOE and USDA Forest
Service Dashek thanks Ms Katherine Mumford Ms Retha Howard and
Ms Abigail M Johnson for technical assistance in the preparation of the
manuscript
Miglani wishes to record his appreciation for Dr Darshan S Brar Honorary
Adjunct Professor School of Agricultural Biotechnology Punjab Agricultural
University Ludhiana India for his valuable technical suggestions Miglani
thanks Dr (Mrs) Parveen Chhuneja Director School of Agricultural
Biotechnology Punjab Agricultural University Ludhiana India for motivat-
ing me to prepare this volume and the Punjab Agricultural University for
providing facilities for this work
We thank the Wiley editorial staff members for their attention to detail
Acknowledgments
1
Plant Cells and their Organelles First Edition Edited by William V Dashek and Gurbachan S Miglani
copy 2017 John Wiley amp Sons Ltd Published 2017 by John Wiley amp Sons Ltd
Cells
Parenchyma chlorenchyma collenchyma and sclerenchyma are the four main
plant cell types (Figure 11 Evert 2006) Meristematic cells which occur in
shoot and root meristems are parenchyma cells Chlorenchyma cells contain
chloroplasts and lack the cell wall thickening layers of collenchyma and scleren-
chyma Certain epidermal cells can be specialized as stomata that are important
in gas exchange (Bergmann and Sack 2007) The diverse cell types (Zhang et al
2001 Yang and Liu 2007) are shown in Table 11 Photomicrographs of certain of
these cell types can be found in Evert (2006) Fahn (1990) Beck (2005) Rudall
(2007) Gunning (2009) MacAdam (2009) Wayne (2009) Beck (2009) Assmann
and Liu (2014) and Noguchi et al (2014)
How do cells ariseCells arise by cell divisions (see Chapter 8 for mitosis and meiosis) in shoot and
root (Figures 12 and 13) meristems (Table 12 Lyndon 1998 McManus and Veit
2001 Murray 2012) The shoot apex is characterized by a tunicandashcorpus organiza-
tion (Steeves and Sussex 1989) The tunica gives rise to the protoderm and its
derivative the epidermis In contrast the corpus provides the procambium which
yields the primary xylem and phloem In addition the ground tissue derives from
the corpus originating the pith and cortex Following divisions cells can differenti-
ate into tissues (Table 13) and organs of the mature plant body (Leyser and Day
2003 Sachs 2005 Dashek and Harrison 2006) The leaf primodium arises on the
apex (Micol and Hake 2003) The mature angiosperm leaf consists of palisade cells
and spongy mesophyll cells sandwiched between the upper and the lower epider-
mis (Figure 14) The epidermis possesses guard cells with associated stomata that
function in gas exchange KNOX genes affect meristem maintenance and suitable
patterning of organ formation (Hake et al 2004) In dissected leaves KNOX genes
are expressed in leaf primordia (Hake et al 2004) Hake et al (2004) suggest that
An introduction to cells and their organellesWilliam V DashekRetired Faculty Adult Degree Program Mary Baldwin College Staunton VA USA
CHapter 1
2 Plant cells and their organelles
KNOX genes may be important in the diversity of leaf form Extensive discussions
of leaf development occur in Sinha (1999) Micol and Hake (2003) and Efroni
et al (2010) Under appropriate stimuli the vegetative apex can be converted to a
floral apex (Figure 15) Photoperiod (Mazumdar 2013) such as short days and
long days and combinations of the two is one such stimulus (Glover 2007
Kinmonth‐Schultz et al 2013) This induction results in the production of florigen
(Turck et al 2008) the flowering hormone (Zeevaart 2006) While early reports
suggest that florigen is an mRNA species (Huang et al 2005) a more recent inves-
tigation indicates that florigen is a protein complex (Yang et al 2007 Taoka et al
2013) Taoka et al state that florigen protein is encoded by the gene Flowering
Locus T in Arabidopsis species (Shresth et al 2014) It is believed that florigen is
induced in leaves and that it moves through the phloem to the shoot apex Plant
hormones (see Appendix A) can influence floral development (Howell 1998)
Gibberellins (Blaacutezquez et al 1998) auxins and jasmonic acid can affect petal
development In contrast auxin can influence gynoecium development The ABC
model has been proposed for regulating the development of floral parts (Soltis
et al 2006) The A gene expression is responsible for sepals while the petals are
the result of co‐expression of A and B genes The B and C genes are responsible for
stamen development and carpels require C genes In certain plants vernalization
(low temperature) can induce flowering in certain plants (Kemi et al 2013)
A diagram of the mature angiosperm plant body is presented in Figure 16 Plant
Primary phloem bres
CO
par
A
Epidermis
Cortex
Phloem
Vascularcambium
Secondaryxylem
Figure 11 Plant cell types Left parenchyma (par) and collenchyma (co) Right
sclerenchyma Source Evert (2006) Reproduced with permission of John Wiley amp Sons
Tab
le 1
1 P
lan
t ce
ll t
ypes
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Epid
erm
al c
ells
Uns
peci
aliz
ed c
ells
one
laye
r of
cel
ls in
thi
ckne
ss o
uter
cov
erin
g of
var
ious
pla
nt p
arts
varia
ble
in s
hape
but
oft
en t
abul
ar
Ever
t (2
006)
Ex
ampl
es
G
uard
cel
lsSp
ecia
lized
epi
derm
al c
ells
cre
scen
t sh
aped
con
tain
chl
orop
last
s f
orm
def
ines
sto
mat
al p
ore
Will
e an
d Lu
cas
(198
4)
Su
bsid
iary
cel
lsC
ells
whi
ch s
ubte
nd t
he s
tom
atal
gua
rd c
ells
http
an
ubis
ru
acz
aM
ain
AN
ATO
MY
gua
rdce
llsh
tml
Tr
icho
mes
An
outg
row
th o
f an
epi
derm
al c
ell
can
be u
nice
llula
r or
mul
ticel
lula
rC
allo
w (2
000)
Pare
nchy
ma
cells
Isod
iam
etric
thi
n‐w
alle
d pr
imar
y ce
ll w
all
in s
ome
inst
ance
s m
ay h
ave
seco
ndar
y w
alls
not
high
ly d
iffer
entia
ted
fun
ctio
n in
pho
tosy
nthe
sis
sec
retio
n o
rgan
ic n
utrie
nt a
nd w
ater
stor
age
reg
ener
atio
n in
wou
nd h
ealin
g
Ever
t (2
006)
and
Saj
eva
and
Mau
seth
(199
1)
Ex
ampl
es
Tr
ansf
er c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
lasm
alem
ma
grea
tly e
xpan
ded
irre
gula
r ex
tens
ions
of
cell
wal
l int
o pr
otop
lasm
tra
nsfe
r di
ssol
ved
subs
tanc
es b
etw
een
adja
cent
cel
l oc
cur
in p
ith
and
cort
ex o
f st
ems
and
root
s p
hoto
synt
hetic
tis
sues
of
leav
es f
lesh
of
succ
ulen
t fr
uits
endo
sper
m o
f se
eds
Das
hek
et a
l (1
971)
and
Off
ler
et a
l
(200
3)
Col
lenc
hym
a ce
llsLa
mel
lar
or p
late
col
lenc
hym
a w
ith t
hick
enin
gs o
n th
e ta
ngen
tial w
alls
Ang
ular
col
lenc
hym
a w
ith t
hick
enin
gs a
roun
d th
e ce
ll w
alls
Pres
ent
in a
eria
l por
tions
of
the
plan
t bo
dy
Vasc
ular
cel
lsEv
ert
(200
6)
Ph
loem
Siev
e ce
lls
Siev
e el
emen
ts
Com
pani
on c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
osse
ss n
umer
ous
plas
mod
esm
atal
con
nect
ions
Opa
rka
and
Turg
eon
(199
9)
Alb
umin
ous
cells
in
gym
nosp
erm
s
Abs
ence
of
star
ch c
ytop
lasm
ic b
ridge
s w
ith s
ieve
cel
ls d
ense
pro
topl
asm
abu
ndan
ce o
f
poly
som
es h
ighl
y co
nden
sed
euch
rom
atin
and
abu
ndan
t m
itoch
ondr
ia
Alo
si a
nd A
lfier
i (19
72) a
nd
Saut
er e
t al
(19
76)
X
ylem
Trac
heid
s
Vess
els
Long
tap
erin
g ce
ll w
ith li
gnifi
ed s
econ
dary
wal
l thi
cken
ings
can
hav
e pi
ts in
wal
ls d
evoi
d of
prot
opla
sm a
t m
atur
ity n
ot a
s sp
ecia
lized
as
vess
els
wid
espr
ead
Tyre
e an
d Zi
mm
erm
an (2
002)
Fuku
da (2
004)
and
Eve
rt (2
006)
(Con
tinue
d )
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Spec
ializ
ed c
ells
ndash H
ydat
hode
s
(mod
ified
par
ts o
f le
aves
and
leaf
tip
s or
mar
gins
)
Con
sist
of
term
inal
tra
chei
ds e
pith
em t
hin‐
wal
led
chlo
ropl
ast‐
defic
ient
cel
ls a
she
ath
with
wat
er p
ores
gut
tatio
n di
scha
rge
of li
quid
con
tain
ing
vario
us d
isso
lved
sol
utes
fro
m a
leaf
rsquos
inte
rior
Lers
ten
and
Cur
tis (1
996)
http
sw
ww
bio
sciu
texa
sed
u a
nd
Mae
da a
nd M
aeda
(198
8)
Latic
ifer
cells
Cel
ls o
r a
serie
s of
cel
ls w
hich
pro
duce
late
xFa
hn (1
990)
Pic
kard
(200
8) a
nd
Botw
ebu
wsp
Edu
Si
mpl
eSi
ngle
-cel
led
C
ompo
und
and
artic
ulat
ed
Uni
on o
f ce
lls c
ompo
und
in o
rigin
and
con
sist
of
long
itudi
nal c
hain
s of
cel
ls w
all s
epar
atin
g
cells
rem
ain
inta
ct c
an b
ecom
e pe
rfor
ated
or
entir
ely
rem
oved
Salt
glan
dsM
odifi
ed t
richo
mes
tw
o‐ce
lled
and
posi
tione
d fla
t on
the
sur
face
in r
ows
para
llel t
o th
e le
af
surf
ace
occ
ur in
Poa
ceae
Ever
t (2
006)
Tan
et
al (
2010
) O
ross
et a
l (1
985)
and
Tho
mso
n et
al
(198
8)
Cap
cel
l ndash la
rge
nucl
eus
and
expa
nded
cut
icle
Nai
doo
and
Nai
doo
(199
8)
Basa
l cel
l ndash n
umer
ous
and
larg
e ex
tens
ive
part
ition
ing
inva
gina
tions
of
plas
mal
emm
a
Nec
tarie
sFo
und
in n
ecta
rines
pro
duce
nec
tar
usua
lly a
t th
e ba
se o
f a
flow
erFa
hn (1
990)
Nic
olso
n an
d N
epi (
2005
)
and
Paiv
a (2
009)
Idio
blas
tsC
ryst
al‐c
onta
inin
g ce
llsLe
rste
n an
d H
orne
r (2
005)
Ex
ampl
e
Ra
phid
esPr
oduc
e ne
edle
‐sha
ped
crys
tals
Muc
ilage
cel
lO
ccur
in a
larg
e nu
mbe
r of
dic
ots
com
mon
in c
erta
in c
acti
slim
y m
ucila
ge p
reve
nts
evap
orat
ion
of w
ater
by
bind
ing
to w
ater
a p
aren
chym
a ce
ll w
hose
dic
tyos
omes
pro
duce
muc
ilage
as
in s
eed
coat
s c
ell w
alls
are
cel
lulo
sic
and
unlig
nifie
d
http
w
ww
sbs
ute
xas
edu
mas
uetl
web
lab
web
chap
9sec
reto
ry9
1‐2
htm
l
Wes
tern
et
al (
2000
) and
Ars
ovsk
ia
et a
l (2
010)
Oil
cells
Spec
ializ
ed c
ells
app
ear
like
larg
e pa
renc
hym
a ce
lls c
an o
ccur
in v
ascu
lar
and
grou
nd t
issu
es
of s
tem
and
leaf
cel
l wal
l has
thr
ee d
istin
ct la
yers
cav
ity is
for
med
aft
er t
he in
ner
wal
l lay
er
has
been
dep
osite
d
Rode
las
et a
l (2
008)
htt
pbr
ittan
ica
com
and
Ler
sten
et
al (
2006
)
Dru
ses
Sphe
rical
agg
rega
tes
of p
rism
atic
cry
stal
sLe
rste
n an
d H
orne
r (2
005)
Cel
ls in
non
‐ang
iosp
erm
s
Br
yoph
ytes
Gem
mae
One
to
man
y ce
llsht
tp
build
ingt
hepr
ide
com
fac
ulty
pgda
viso
nbr
yolo
gy_l
inks
htm
Hyd
roid
sW
ater
‐con
duct
ing
cells
http
w
ww
Bio
logy
‐onl
ine
org
Lept
oids
ndash P
terid
ophy
tes
Org
anic
com
poun
d‐co
nduc
ting
cells
spo
roge
nous
cel
ls p
rese
nt in
spo
rang
ia o
f so
ri
Tab
le 1
1 (
Con
tin
ued
)
An introduction to cells and their organelles 5
development is discussed in Fosket (1999) Moore and Clark (1995) Greenland
(2003) Leyser and Day (2003) and Rudall (2007)
What is the composition of cellsCertain plant components exhibit polar growth for example the tip growth of
pollen tubes (Hepler et al 2001) The tubes elongate via the fusion of Golgi‐
derived vesicles with the plasmalemma and subsequent deposition of the vesi-
clesrsquo contents into the cell wall (Taylor and Hepler 1997 Parton et al 2001 and
others as reviewed in Malho (2006a 2006b)) In 2007 Dalgic and Dane (2005)
published a diagram depicting the now known tube‐tip structural elements and
physiological processes that facilitate tube elongation The diagram represents a
Figure 12 Angiosperm shoot meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
Figure 13 Angiosperm root meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
6 Plant cells and their organelles
significant advance over the early studies of pollen tubes as it assigns function to
ultrastructural components for example signalling molecules the Rho family of
GTPases and phosphatidylinositol 45 bisphosphate appear to be localized in the
apical plasma membrane Besides pollen tubes root hairs exhibit polar growth
Cell organelles ndash an introduction
Organelles are required for plant growth development and function (Sadava
1993 Gillham 1994 Herrmann 1994 Agrawal 2011) These organelles
(Figure 17) are the loci for a myriad of physiological and biochemical processes
(Tobin 1992 Daniell and Chase 2004 ndash see individual chapters)
There are many diagrams of a generalized plant cell Some of these are available
at wwwexplorebiologycom httpwwwdaviddarlinginfoimagesplant_celljpg
Table 12 Meristems and their derivatives
Meristems Derivatives
Primary
Protoderm Epidermis
From tunica (Evert 2006)
Procambium (provascular) Primary xylem and phloem
From corpus (Evert 2006) Vascular cambium
Ground Ground tissue pith and cortex
Lateral
Vascular cambium
Fusiform initials Secondary xylem
Secondary phloem
Ray initials (Evert 2006) Ray cells
Cork cambium
Phellogen Replaces the epidermis when cork cambium initiates stem girth
increase composed of lsquoboxlikersquo cork cells which are dead at
maturity protoplasm secretes suberin some cork cells that are
loosely packed give rise to lenticels which function in gas exchange
between the air and the stemrsquos interior httpwwwBiology‐online
org Evert (2006) httpwwwvebrioSceincevunlenvirut
Periderm (Evert 2006)
Phelloderm Parenchyma cells produced on the inside by the cork cambium
Meristems are discussed by Steeves and Sussex (1989)
Table 13 Plant tissues
Tissue system
Meristematic Ground Vascular Dermal
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
This edition first published 2017 copy 2017 by John Wiley amp Sons Ltd
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Library of Congress Cataloging‐in‐Publication Data
Names Dashek William V editor | Miglani Gurbachan S editorTitle Plant cells and their organelles by William V Dashek Gurbachan S MiglaniDescription [Hoboken NJ] Wiley 2017 | Includes bibliographical references and indexIdentifiers LCCN 2016024724 (print) | LCCN 2016026083 (ebook) | ISBN 9780470976869 (cloth) |
ISBN 9781118924761 (pdf) | ISBN 9781118924754 (epub)Subjects LCSH Plant cells and tissuesndashTextbooksClassification LCC QK725 D36 2017 (print) | LCC QK725 (ebook) | DDC 5813ndashdc23LC record available at httpslccnlocgov2016024724
A catalogue record for this book is available from the British Library
Wiley also publishes its books in a variety of electronic formats Some content that appears in print may not be available in electronic books
Cover image copy Alan John Lander PhillipsGettyimages
Set in 9513pt Meridien by SPi Global Pondicherry India
1 2017
v
Contributors ix
Preface xi
Acknowledgments xii
1 An introduction to cells and their organelles 1
William V Dashek
Cells 1
Cell organelles ndash an introduction 6
Ion channels 10
Proton pumps 14
Water channels 14
Carriers 15
Cell death 17
References 18
Further reading 24
2 Isolation and characterization of subcellular organelles from plant cells 25
Milee Agarwal P Desai and Harish Padh
Isolation of subcellular organelles 26
Identification and characterization of isolated organelles 33
Summary 39
References 39
Further reading 41
3 Endoplasmic reticulum 42
William V Dashek
Structure 42
Chemical composition 42
Biogenesis 45
Functions 45
Posttranslational events 49
Inhibitors 53
In vitro protein synthesis 54
Other functions 54
References 54
Further reading 60
Contents
vi Contents
4 The Golgi apparatus 61
D Davis TE Wilkop and Georgia Drakakaki
The Golgi apparatus 61
Plant Golgi introduction 66
Structure and organization 69
Golgi‐mediated vesicular trafficking 71
Plant Golgi‐dependent cellular processes 74
Imaging and visualization 76
Isolation and analysis 78
Golgi genetics and genomics 81
Significance 84
Acknowledgment 85
References 85
Further reading 87
5 Microbodies 88
Robert Donaldson
Introducing peroxisomes 88
Leaf peroxisomes 89
Peroxisomes in oil seeds and pollen 91
References 107
Further reading 109
6 Microtubules intermediate filaments and actin filaments 110
William V Dashek
Microtubules 110
Intermediate filaments 113
Actin filaments (microfilaments) 116
References 119
Further reading 124
7 The mitochondrion 125
Ray J Rose Terence W‐Y Tiew and William V Dashek
Structure and dynamics 125
The mitochondrial genome 128
Comparison of the mitochondrial genome with chloroplast and nuclear
genomes 131
The mitochondrial proteome and protein import 132
Respiratory metabolite transporters 133
The electron transport chain and oxidative phosphorylation 133
The alternative electron transfer chain in plant mitochondria 139
Plant mitochondria stress responses and programmed cell death 139
Other functions of plant mitochondria 140
References 144
Further reading 145
Contents vii
8 Nucleus 146
Yogesh Vikal and Dasmeet Kaur
Structural organization of the NE 147
Nuclear pores 152
The nucleolus 157
Chromatin and chromosomes 165
DNA structure 170
DNA replication 173
RNA structure function and synthesis 176
Nucleocytoplasmic transport nuclear import and nuclear export 183
The dynamics of NE biogenesis during mitosis 188
The dynamics of nuclear pore complex biogenesis 196
Cell cycle control 200
Summary 205
References 206
Further reading 207
9 Plant cell walls 209
James E Bidlack and William V Dashek
Introduction 209
Structure 209
Biosynthesis 216
Chemical composition 217
Biogenesis 222
Function 225
References 231
Further reading 238
10 Plastid structure and genomics 239
Gurbachan S Miglani
Plastid structure 239
Different forms of plastids 240
Plastid stromules 248
Chlorophyll biosynthesis 248
Plastid genomics 250
Sequenced plastomes 253
Promiscuous DNA 258
Plastid genome organization 260
Plastid gene organization expression and regulation 265
Systems biology approach in understanding chloroplast development 269
Chloroplast genetic engineering 284
Recent trends in chloroplast research 289
Summary 293
References 294
Further reading 299
viii Contents
11 Photosynthesis 300
J Kenneth Hoober
Introduction 300
Evolution of photosynthesis 301
Development of the chloroplast 310
Absorption of light energy 317
Generation of end products 324
Distribution of the photosystems in thylakoid membranes 329
Photoinhibition damage and repair of the PS II reaction center 332
Protection of PS II by carotenoids 332
Incorporation of carbon as CO2 into carbohydrate 334
End products of carbon assimilation 346
Conclusions for the reactions of photosynthesis 348
References 348
Further reading 350
12 Vacuoles and protein bodies 351
William V Dashek and Amy M Clore
Vacuoles 351
PBs and other protein storage compartments 359
References 365
Further reading 370
13 Systems biology in plant cells and their organelles 371
Rajdeep Kaur Grewal Saptarshi Sinha and Soumen Roy
Systems biologymdashldquoomicsrdquo 371
Genomics 373
Lipidomics 378
Metabolomics 380
Proteomics 382
Transcriptomics 384
Synthetic biology 386
Acknowledgments 388
References 389
Further reading 391
Appendix A 392
Appendix B 400
Appendix C 403
Index 407
ix
Milee AgarwalScientist
Pharmacology and Toxicology Department
BV Patel PERD Centre
Ahmedabad Gujarat India
James E BidlackProfessor of Biology and CURE‐STEM
Scholar
Department of Biology
University of Central Oklahoma
Edmond OK USA
Amy M CloreProfessor of Biology
Division of Natural Sciences
New College of Florida
Sarasota FL USA
William V DashekRetired Faculty
Adult Degree Program
Mary Baldwin College
Staunton VA USA
D DavisGraduate Student
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
P DesaiScientist
Cellular and Molecular Biology Department
BV Patel PERD Centre
Ahmedabad Gujarat India
Robert DonaldsonProfessor
Department of Biological Sciences
George Washington University
Washington DC USA
Georgia DrakakakiAssociate Professor
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
Rajdeep Kaur GrewalSenior Research Fellow
Department of Physics
Bose Institute
Kolkata India
J Kenneth HooberProfessor Emeritus
School of Life Sciences
Center for Photosynthesis
Arizona State University
Tempe AZ USA
Dasmeet KaurResearch Assistant
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
Gurbachan S MiglaniVisiting Professor
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
Contributors
x Contributors
Harish PadhVice-Chancellor
Sardar Patel University
Vallabh Vidyanagar Anand
Gujarat India
Ray J RoseEmeritus Professor
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Soumen RoyAssociate Professor
Department of Physics
Bose Institute
Kolkata India
Saptarshi SinhaSenior Research Fellow
Department of Physics
Bose Institute
Kolkata India
Terence W‐Y TiewGraduate Student
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Yogesh VikalSenior Geneticist
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
TE WilkopSenior Project Scientist
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
xi
Plant Cells and their Organelles is an advanced textbook to enhance the plant
biology studentrsquos knowledge of the structure and function of plant cells and their
organelles The book assumes that the student has had introductory courses in
plant science and chemistry The book emphasizes the research literature in
plant cell biology concerning cell and organellar structure However the litera-
ture from plant physiology molecular genetics and biochemistry has been
utilized to augment the discussions of cell and organellar function
Preface
xii
Dashek is grateful to Drs WG Rosen WF Millington and DTA Lamport for
training enabling a career in teaching and research in plant biology Dashek
appreciates the grant support of the USArsquos NIH NSF DOE and USDA Forest
Service Dashek thanks Ms Katherine Mumford Ms Retha Howard and
Ms Abigail M Johnson for technical assistance in the preparation of the
manuscript
Miglani wishes to record his appreciation for Dr Darshan S Brar Honorary
Adjunct Professor School of Agricultural Biotechnology Punjab Agricultural
University Ludhiana India for his valuable technical suggestions Miglani
thanks Dr (Mrs) Parveen Chhuneja Director School of Agricultural
Biotechnology Punjab Agricultural University Ludhiana India for motivat-
ing me to prepare this volume and the Punjab Agricultural University for
providing facilities for this work
We thank the Wiley editorial staff members for their attention to detail
Acknowledgments
1
Plant Cells and their Organelles First Edition Edited by William V Dashek and Gurbachan S Miglani
copy 2017 John Wiley amp Sons Ltd Published 2017 by John Wiley amp Sons Ltd
Cells
Parenchyma chlorenchyma collenchyma and sclerenchyma are the four main
plant cell types (Figure 11 Evert 2006) Meristematic cells which occur in
shoot and root meristems are parenchyma cells Chlorenchyma cells contain
chloroplasts and lack the cell wall thickening layers of collenchyma and scleren-
chyma Certain epidermal cells can be specialized as stomata that are important
in gas exchange (Bergmann and Sack 2007) The diverse cell types (Zhang et al
2001 Yang and Liu 2007) are shown in Table 11 Photomicrographs of certain of
these cell types can be found in Evert (2006) Fahn (1990) Beck (2005) Rudall
(2007) Gunning (2009) MacAdam (2009) Wayne (2009) Beck (2009) Assmann
and Liu (2014) and Noguchi et al (2014)
How do cells ariseCells arise by cell divisions (see Chapter 8 for mitosis and meiosis) in shoot and
root (Figures 12 and 13) meristems (Table 12 Lyndon 1998 McManus and Veit
2001 Murray 2012) The shoot apex is characterized by a tunicandashcorpus organiza-
tion (Steeves and Sussex 1989) The tunica gives rise to the protoderm and its
derivative the epidermis In contrast the corpus provides the procambium which
yields the primary xylem and phloem In addition the ground tissue derives from
the corpus originating the pith and cortex Following divisions cells can differenti-
ate into tissues (Table 13) and organs of the mature plant body (Leyser and Day
2003 Sachs 2005 Dashek and Harrison 2006) The leaf primodium arises on the
apex (Micol and Hake 2003) The mature angiosperm leaf consists of palisade cells
and spongy mesophyll cells sandwiched between the upper and the lower epider-
mis (Figure 14) The epidermis possesses guard cells with associated stomata that
function in gas exchange KNOX genes affect meristem maintenance and suitable
patterning of organ formation (Hake et al 2004) In dissected leaves KNOX genes
are expressed in leaf primordia (Hake et al 2004) Hake et al (2004) suggest that
An introduction to cells and their organellesWilliam V DashekRetired Faculty Adult Degree Program Mary Baldwin College Staunton VA USA
CHapter 1
2 Plant cells and their organelles
KNOX genes may be important in the diversity of leaf form Extensive discussions
of leaf development occur in Sinha (1999) Micol and Hake (2003) and Efroni
et al (2010) Under appropriate stimuli the vegetative apex can be converted to a
floral apex (Figure 15) Photoperiod (Mazumdar 2013) such as short days and
long days and combinations of the two is one such stimulus (Glover 2007
Kinmonth‐Schultz et al 2013) This induction results in the production of florigen
(Turck et al 2008) the flowering hormone (Zeevaart 2006) While early reports
suggest that florigen is an mRNA species (Huang et al 2005) a more recent inves-
tigation indicates that florigen is a protein complex (Yang et al 2007 Taoka et al
2013) Taoka et al state that florigen protein is encoded by the gene Flowering
Locus T in Arabidopsis species (Shresth et al 2014) It is believed that florigen is
induced in leaves and that it moves through the phloem to the shoot apex Plant
hormones (see Appendix A) can influence floral development (Howell 1998)
Gibberellins (Blaacutezquez et al 1998) auxins and jasmonic acid can affect petal
development In contrast auxin can influence gynoecium development The ABC
model has been proposed for regulating the development of floral parts (Soltis
et al 2006) The A gene expression is responsible for sepals while the petals are
the result of co‐expression of A and B genes The B and C genes are responsible for
stamen development and carpels require C genes In certain plants vernalization
(low temperature) can induce flowering in certain plants (Kemi et al 2013)
A diagram of the mature angiosperm plant body is presented in Figure 16 Plant
Primary phloem bres
CO
par
A
Epidermis
Cortex
Phloem
Vascularcambium
Secondaryxylem
Figure 11 Plant cell types Left parenchyma (par) and collenchyma (co) Right
sclerenchyma Source Evert (2006) Reproduced with permission of John Wiley amp Sons
Tab
le 1
1 P
lan
t ce
ll t
ypes
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Epid
erm
al c
ells
Uns
peci
aliz
ed c
ells
one
laye
r of
cel
ls in
thi
ckne
ss o
uter
cov
erin
g of
var
ious
pla
nt p
arts
varia
ble
in s
hape
but
oft
en t
abul
ar
Ever
t (2
006)
Ex
ampl
es
G
uard
cel
lsSp
ecia
lized
epi
derm
al c
ells
cre
scen
t sh
aped
con
tain
chl
orop
last
s f
orm
def
ines
sto
mat
al p
ore
Will
e an
d Lu
cas
(198
4)
Su
bsid
iary
cel
lsC
ells
whi
ch s
ubte
nd t
he s
tom
atal
gua
rd c
ells
http
an
ubis
ru
acz
aM
ain
AN
ATO
MY
gua
rdce
llsh
tml
Tr
icho
mes
An
outg
row
th o
f an
epi
derm
al c
ell
can
be u
nice
llula
r or
mul
ticel
lula
rC
allo
w (2
000)
Pare
nchy
ma
cells
Isod
iam
etric
thi
n‐w
alle
d pr
imar
y ce
ll w
all
in s
ome
inst
ance
s m
ay h
ave
seco
ndar
y w
alls
not
high
ly d
iffer
entia
ted
fun
ctio
n in
pho
tosy
nthe
sis
sec
retio
n o
rgan
ic n
utrie
nt a
nd w
ater
stor
age
reg
ener
atio
n in
wou
nd h
ealin
g
Ever
t (2
006)
and
Saj
eva
and
Mau
seth
(199
1)
Ex
ampl
es
Tr
ansf
er c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
lasm
alem
ma
grea
tly e
xpan
ded
irre
gula
r ex
tens
ions
of
cell
wal
l int
o pr
otop
lasm
tra
nsfe
r di
ssol
ved
subs
tanc
es b
etw
een
adja
cent
cel
l oc
cur
in p
ith
and
cort
ex o
f st
ems
and
root
s p
hoto
synt
hetic
tis
sues
of
leav
es f
lesh
of
succ
ulen
t fr
uits
endo
sper
m o
f se
eds
Das
hek
et a
l (1
971)
and
Off
ler
et a
l
(200
3)
Col
lenc
hym
a ce
llsLa
mel
lar
or p
late
col
lenc
hym
a w
ith t
hick
enin
gs o
n th
e ta
ngen
tial w
alls
Ang
ular
col
lenc
hym
a w
ith t
hick
enin
gs a
roun
d th
e ce
ll w
alls
Pres
ent
in a
eria
l por
tions
of
the
plan
t bo
dy
Vasc
ular
cel
lsEv
ert
(200
6)
Ph
loem
Siev
e ce
lls
Siev
e el
emen
ts
Com
pani
on c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
osse
ss n
umer
ous
plas
mod
esm
atal
con
nect
ions
Opa
rka
and
Turg
eon
(199
9)
Alb
umin
ous
cells
in
gym
nosp
erm
s
Abs
ence
of
star
ch c
ytop
lasm
ic b
ridge
s w
ith s
ieve
cel
ls d
ense
pro
topl
asm
abu
ndan
ce o
f
poly
som
es h
ighl
y co
nden
sed
euch
rom
atin
and
abu
ndan
t m
itoch
ondr
ia
Alo
si a
nd A
lfier
i (19
72) a
nd
Saut
er e
t al
(19
76)
X
ylem
Trac
heid
s
Vess
els
Long
tap
erin
g ce
ll w
ith li
gnifi
ed s
econ
dary
wal
l thi
cken
ings
can
hav
e pi
ts in
wal
ls d
evoi
d of
prot
opla
sm a
t m
atur
ity n
ot a
s sp
ecia
lized
as
vess
els
wid
espr
ead
Tyre
e an
d Zi
mm
erm
an (2
002)
Fuku
da (2
004)
and
Eve
rt (2
006)
(Con
tinue
d )
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Spec
ializ
ed c
ells
ndash H
ydat
hode
s
(mod
ified
par
ts o
f le
aves
and
leaf
tip
s or
mar
gins
)
Con
sist
of
term
inal
tra
chei
ds e
pith
em t
hin‐
wal
led
chlo
ropl
ast‐
defic
ient
cel
ls a
she
ath
with
wat
er p
ores
gut
tatio
n di
scha
rge
of li
quid
con
tain
ing
vario
us d
isso
lved
sol
utes
fro
m a
leaf
rsquos
inte
rior
Lers
ten
and
Cur
tis (1
996)
http
sw
ww
bio
sciu
texa
sed
u a
nd
Mae
da a
nd M
aeda
(198
8)
Latic
ifer
cells
Cel
ls o
r a
serie
s of
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ls w
hich
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duce
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xFa
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kard
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8) a
nd
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ebu
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ngle
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ompo
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ulat
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on o
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lls c
ompo
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rigin
and
con
sist
of
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itudi
nal c
hain
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ls w
all s
epar
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ct c
an b
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rfor
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oved
Salt
glan
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odifi
ed t
richo
mes
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o‐ce
lled
and
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tione
d fla
t on
the
sur
face
in r
ows
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llel t
o th
e le
af
surf
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occ
ur in
Poa
ceae
Ever
t (2
006)
Tan
et
al (
2010
) O
ross
et a
l (1
985)
and
Tho
mso
n et
al
(198
8)
Cap
cel
l ndash la
rge
nucl
eus
and
expa
nded
cut
icle
Nai
doo
and
Nai
doo
(199
8)
Basa
l cel
l ndash n
umer
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and
larg
e ex
tens
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part
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inva
gina
tions
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plas
mal
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Nec
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tar
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lly a
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Nic
olso
n an
d N
epi (
2005
)
and
Paiv
a (2
009)
Idio
blas
tsC
ryst
al‐c
onta
inin
g ce
llsLe
rste
n an
d H
orne
r (2
005)
Ex
ampl
e
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phid
esPr
oduc
e ne
edle
‐sha
ped
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tals
Muc
ilage
cel
lO
ccur
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e nu
mbe
r of
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ots
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of w
ater
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ater
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hose
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omes
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ilage
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eed
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http
w
ww
sbs
ute
xas
edu
mas
uetl
web
lab
web
chap
9sec
reto
ry9
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htm
l
Wes
tern
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) and
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Oil
cells
Spec
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htt
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)
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Sphe
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atic
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orne
r (2
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One
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ide
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fac
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inks
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ater
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Bio
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ine
org
Lept
oids
ndash P
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nt in
spo
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Tab
le 1
1 (
Con
tin
ued
)
An introduction to cells and their organelles 5
development is discussed in Fosket (1999) Moore and Clark (1995) Greenland
(2003) Leyser and Day (2003) and Rudall (2007)
What is the composition of cellsCertain plant components exhibit polar growth for example the tip growth of
pollen tubes (Hepler et al 2001) The tubes elongate via the fusion of Golgi‐
derived vesicles with the plasmalemma and subsequent deposition of the vesi-
clesrsquo contents into the cell wall (Taylor and Hepler 1997 Parton et al 2001 and
others as reviewed in Malho (2006a 2006b)) In 2007 Dalgic and Dane (2005)
published a diagram depicting the now known tube‐tip structural elements and
physiological processes that facilitate tube elongation The diagram represents a
Figure 12 Angiosperm shoot meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
Figure 13 Angiosperm root meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
6 Plant cells and their organelles
significant advance over the early studies of pollen tubes as it assigns function to
ultrastructural components for example signalling molecules the Rho family of
GTPases and phosphatidylinositol 45 bisphosphate appear to be localized in the
apical plasma membrane Besides pollen tubes root hairs exhibit polar growth
Cell organelles ndash an introduction
Organelles are required for plant growth development and function (Sadava
1993 Gillham 1994 Herrmann 1994 Agrawal 2011) These organelles
(Figure 17) are the loci for a myriad of physiological and biochemical processes
(Tobin 1992 Daniell and Chase 2004 ndash see individual chapters)
There are many diagrams of a generalized plant cell Some of these are available
at wwwexplorebiologycom httpwwwdaviddarlinginfoimagesplant_celljpg
Table 12 Meristems and their derivatives
Meristems Derivatives
Primary
Protoderm Epidermis
From tunica (Evert 2006)
Procambium (provascular) Primary xylem and phloem
From corpus (Evert 2006) Vascular cambium
Ground Ground tissue pith and cortex
Lateral
Vascular cambium
Fusiform initials Secondary xylem
Secondary phloem
Ray initials (Evert 2006) Ray cells
Cork cambium
Phellogen Replaces the epidermis when cork cambium initiates stem girth
increase composed of lsquoboxlikersquo cork cells which are dead at
maturity protoplasm secretes suberin some cork cells that are
loosely packed give rise to lenticels which function in gas exchange
between the air and the stemrsquos interior httpwwwBiology‐online
org Evert (2006) httpwwwvebrioSceincevunlenvirut
Periderm (Evert 2006)
Phelloderm Parenchyma cells produced on the inside by the cork cambium
Meristems are discussed by Steeves and Sussex (1989)
Table 13 Plant tissues
Tissue system
Meristematic Ground Vascular Dermal
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
v
Contributors ix
Preface xi
Acknowledgments xii
1 An introduction to cells and their organelles 1
William V Dashek
Cells 1
Cell organelles ndash an introduction 6
Ion channels 10
Proton pumps 14
Water channels 14
Carriers 15
Cell death 17
References 18
Further reading 24
2 Isolation and characterization of subcellular organelles from plant cells 25
Milee Agarwal P Desai and Harish Padh
Isolation of subcellular organelles 26
Identification and characterization of isolated organelles 33
Summary 39
References 39
Further reading 41
3 Endoplasmic reticulum 42
William V Dashek
Structure 42
Chemical composition 42
Biogenesis 45
Functions 45
Posttranslational events 49
Inhibitors 53
In vitro protein synthesis 54
Other functions 54
References 54
Further reading 60
Contents
vi Contents
4 The Golgi apparatus 61
D Davis TE Wilkop and Georgia Drakakaki
The Golgi apparatus 61
Plant Golgi introduction 66
Structure and organization 69
Golgi‐mediated vesicular trafficking 71
Plant Golgi‐dependent cellular processes 74
Imaging and visualization 76
Isolation and analysis 78
Golgi genetics and genomics 81
Significance 84
Acknowledgment 85
References 85
Further reading 87
5 Microbodies 88
Robert Donaldson
Introducing peroxisomes 88
Leaf peroxisomes 89
Peroxisomes in oil seeds and pollen 91
References 107
Further reading 109
6 Microtubules intermediate filaments and actin filaments 110
William V Dashek
Microtubules 110
Intermediate filaments 113
Actin filaments (microfilaments) 116
References 119
Further reading 124
7 The mitochondrion 125
Ray J Rose Terence W‐Y Tiew and William V Dashek
Structure and dynamics 125
The mitochondrial genome 128
Comparison of the mitochondrial genome with chloroplast and nuclear
genomes 131
The mitochondrial proteome and protein import 132
Respiratory metabolite transporters 133
The electron transport chain and oxidative phosphorylation 133
The alternative electron transfer chain in plant mitochondria 139
Plant mitochondria stress responses and programmed cell death 139
Other functions of plant mitochondria 140
References 144
Further reading 145
Contents vii
8 Nucleus 146
Yogesh Vikal and Dasmeet Kaur
Structural organization of the NE 147
Nuclear pores 152
The nucleolus 157
Chromatin and chromosomes 165
DNA structure 170
DNA replication 173
RNA structure function and synthesis 176
Nucleocytoplasmic transport nuclear import and nuclear export 183
The dynamics of NE biogenesis during mitosis 188
The dynamics of nuclear pore complex biogenesis 196
Cell cycle control 200
Summary 205
References 206
Further reading 207
9 Plant cell walls 209
James E Bidlack and William V Dashek
Introduction 209
Structure 209
Biosynthesis 216
Chemical composition 217
Biogenesis 222
Function 225
References 231
Further reading 238
10 Plastid structure and genomics 239
Gurbachan S Miglani
Plastid structure 239
Different forms of plastids 240
Plastid stromules 248
Chlorophyll biosynthesis 248
Plastid genomics 250
Sequenced plastomes 253
Promiscuous DNA 258
Plastid genome organization 260
Plastid gene organization expression and regulation 265
Systems biology approach in understanding chloroplast development 269
Chloroplast genetic engineering 284
Recent trends in chloroplast research 289
Summary 293
References 294
Further reading 299
viii Contents
11 Photosynthesis 300
J Kenneth Hoober
Introduction 300
Evolution of photosynthesis 301
Development of the chloroplast 310
Absorption of light energy 317
Generation of end products 324
Distribution of the photosystems in thylakoid membranes 329
Photoinhibition damage and repair of the PS II reaction center 332
Protection of PS II by carotenoids 332
Incorporation of carbon as CO2 into carbohydrate 334
End products of carbon assimilation 346
Conclusions for the reactions of photosynthesis 348
References 348
Further reading 350
12 Vacuoles and protein bodies 351
William V Dashek and Amy M Clore
Vacuoles 351
PBs and other protein storage compartments 359
References 365
Further reading 370
13 Systems biology in plant cells and their organelles 371
Rajdeep Kaur Grewal Saptarshi Sinha and Soumen Roy
Systems biologymdashldquoomicsrdquo 371
Genomics 373
Lipidomics 378
Metabolomics 380
Proteomics 382
Transcriptomics 384
Synthetic biology 386
Acknowledgments 388
References 389
Further reading 391
Appendix A 392
Appendix B 400
Appendix C 403
Index 407
ix
Milee AgarwalScientist
Pharmacology and Toxicology Department
BV Patel PERD Centre
Ahmedabad Gujarat India
James E BidlackProfessor of Biology and CURE‐STEM
Scholar
Department of Biology
University of Central Oklahoma
Edmond OK USA
Amy M CloreProfessor of Biology
Division of Natural Sciences
New College of Florida
Sarasota FL USA
William V DashekRetired Faculty
Adult Degree Program
Mary Baldwin College
Staunton VA USA
D DavisGraduate Student
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
P DesaiScientist
Cellular and Molecular Biology Department
BV Patel PERD Centre
Ahmedabad Gujarat India
Robert DonaldsonProfessor
Department of Biological Sciences
George Washington University
Washington DC USA
Georgia DrakakakiAssociate Professor
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
Rajdeep Kaur GrewalSenior Research Fellow
Department of Physics
Bose Institute
Kolkata India
J Kenneth HooberProfessor Emeritus
School of Life Sciences
Center for Photosynthesis
Arizona State University
Tempe AZ USA
Dasmeet KaurResearch Assistant
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
Gurbachan S MiglaniVisiting Professor
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
Contributors
x Contributors
Harish PadhVice-Chancellor
Sardar Patel University
Vallabh Vidyanagar Anand
Gujarat India
Ray J RoseEmeritus Professor
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Soumen RoyAssociate Professor
Department of Physics
Bose Institute
Kolkata India
Saptarshi SinhaSenior Research Fellow
Department of Physics
Bose Institute
Kolkata India
Terence W‐Y TiewGraduate Student
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Yogesh VikalSenior Geneticist
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
TE WilkopSenior Project Scientist
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
xi
Plant Cells and their Organelles is an advanced textbook to enhance the plant
biology studentrsquos knowledge of the structure and function of plant cells and their
organelles The book assumes that the student has had introductory courses in
plant science and chemistry The book emphasizes the research literature in
plant cell biology concerning cell and organellar structure However the litera-
ture from plant physiology molecular genetics and biochemistry has been
utilized to augment the discussions of cell and organellar function
Preface
xii
Dashek is grateful to Drs WG Rosen WF Millington and DTA Lamport for
training enabling a career in teaching and research in plant biology Dashek
appreciates the grant support of the USArsquos NIH NSF DOE and USDA Forest
Service Dashek thanks Ms Katherine Mumford Ms Retha Howard and
Ms Abigail M Johnson for technical assistance in the preparation of the
manuscript
Miglani wishes to record his appreciation for Dr Darshan S Brar Honorary
Adjunct Professor School of Agricultural Biotechnology Punjab Agricultural
University Ludhiana India for his valuable technical suggestions Miglani
thanks Dr (Mrs) Parveen Chhuneja Director School of Agricultural
Biotechnology Punjab Agricultural University Ludhiana India for motivat-
ing me to prepare this volume and the Punjab Agricultural University for
providing facilities for this work
We thank the Wiley editorial staff members for their attention to detail
Acknowledgments
1
Plant Cells and their Organelles First Edition Edited by William V Dashek and Gurbachan S Miglani
copy 2017 John Wiley amp Sons Ltd Published 2017 by John Wiley amp Sons Ltd
Cells
Parenchyma chlorenchyma collenchyma and sclerenchyma are the four main
plant cell types (Figure 11 Evert 2006) Meristematic cells which occur in
shoot and root meristems are parenchyma cells Chlorenchyma cells contain
chloroplasts and lack the cell wall thickening layers of collenchyma and scleren-
chyma Certain epidermal cells can be specialized as stomata that are important
in gas exchange (Bergmann and Sack 2007) The diverse cell types (Zhang et al
2001 Yang and Liu 2007) are shown in Table 11 Photomicrographs of certain of
these cell types can be found in Evert (2006) Fahn (1990) Beck (2005) Rudall
(2007) Gunning (2009) MacAdam (2009) Wayne (2009) Beck (2009) Assmann
and Liu (2014) and Noguchi et al (2014)
How do cells ariseCells arise by cell divisions (see Chapter 8 for mitosis and meiosis) in shoot and
root (Figures 12 and 13) meristems (Table 12 Lyndon 1998 McManus and Veit
2001 Murray 2012) The shoot apex is characterized by a tunicandashcorpus organiza-
tion (Steeves and Sussex 1989) The tunica gives rise to the protoderm and its
derivative the epidermis In contrast the corpus provides the procambium which
yields the primary xylem and phloem In addition the ground tissue derives from
the corpus originating the pith and cortex Following divisions cells can differenti-
ate into tissues (Table 13) and organs of the mature plant body (Leyser and Day
2003 Sachs 2005 Dashek and Harrison 2006) The leaf primodium arises on the
apex (Micol and Hake 2003) The mature angiosperm leaf consists of palisade cells
and spongy mesophyll cells sandwiched between the upper and the lower epider-
mis (Figure 14) The epidermis possesses guard cells with associated stomata that
function in gas exchange KNOX genes affect meristem maintenance and suitable
patterning of organ formation (Hake et al 2004) In dissected leaves KNOX genes
are expressed in leaf primordia (Hake et al 2004) Hake et al (2004) suggest that
An introduction to cells and their organellesWilliam V DashekRetired Faculty Adult Degree Program Mary Baldwin College Staunton VA USA
CHapter 1
2 Plant cells and their organelles
KNOX genes may be important in the diversity of leaf form Extensive discussions
of leaf development occur in Sinha (1999) Micol and Hake (2003) and Efroni
et al (2010) Under appropriate stimuli the vegetative apex can be converted to a
floral apex (Figure 15) Photoperiod (Mazumdar 2013) such as short days and
long days and combinations of the two is one such stimulus (Glover 2007
Kinmonth‐Schultz et al 2013) This induction results in the production of florigen
(Turck et al 2008) the flowering hormone (Zeevaart 2006) While early reports
suggest that florigen is an mRNA species (Huang et al 2005) a more recent inves-
tigation indicates that florigen is a protein complex (Yang et al 2007 Taoka et al
2013) Taoka et al state that florigen protein is encoded by the gene Flowering
Locus T in Arabidopsis species (Shresth et al 2014) It is believed that florigen is
induced in leaves and that it moves through the phloem to the shoot apex Plant
hormones (see Appendix A) can influence floral development (Howell 1998)
Gibberellins (Blaacutezquez et al 1998) auxins and jasmonic acid can affect petal
development In contrast auxin can influence gynoecium development The ABC
model has been proposed for regulating the development of floral parts (Soltis
et al 2006) The A gene expression is responsible for sepals while the petals are
the result of co‐expression of A and B genes The B and C genes are responsible for
stamen development and carpels require C genes In certain plants vernalization
(low temperature) can induce flowering in certain plants (Kemi et al 2013)
A diagram of the mature angiosperm plant body is presented in Figure 16 Plant
Primary phloem bres
CO
par
A
Epidermis
Cortex
Phloem
Vascularcambium
Secondaryxylem
Figure 11 Plant cell types Left parenchyma (par) and collenchyma (co) Right
sclerenchyma Source Evert (2006) Reproduced with permission of John Wiley amp Sons
Tab
le 1
1 P
lan
t ce
ll t
ypes
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Epid
erm
al c
ells
Uns
peci
aliz
ed c
ells
one
laye
r of
cel
ls in
thi
ckne
ss o
uter
cov
erin
g of
var
ious
pla
nt p
arts
varia
ble
in s
hape
but
oft
en t
abul
ar
Ever
t (2
006)
Ex
ampl
es
G
uard
cel
lsSp
ecia
lized
epi
derm
al c
ells
cre
scen
t sh
aped
con
tain
chl
orop
last
s f
orm
def
ines
sto
mat
al p
ore
Will
e an
d Lu
cas
(198
4)
Su
bsid
iary
cel
lsC
ells
whi
ch s
ubte
nd t
he s
tom
atal
gua
rd c
ells
http
an
ubis
ru
acz
aM
ain
AN
ATO
MY
gua
rdce
llsh
tml
Tr
icho
mes
An
outg
row
th o
f an
epi
derm
al c
ell
can
be u
nice
llula
r or
mul
ticel
lula
rC
allo
w (2
000)
Pare
nchy
ma
cells
Isod
iam
etric
thi
n‐w
alle
d pr
imar
y ce
ll w
all
in s
ome
inst
ance
s m
ay h
ave
seco
ndar
y w
alls
not
high
ly d
iffer
entia
ted
fun
ctio
n in
pho
tosy
nthe
sis
sec
retio
n o
rgan
ic n
utrie
nt a
nd w
ater
stor
age
reg
ener
atio
n in
wou
nd h
ealin
g
Ever
t (2
006)
and
Saj
eva
and
Mau
seth
(199
1)
Ex
ampl
es
Tr
ansf
er c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
lasm
alem
ma
grea
tly e
xpan
ded
irre
gula
r ex
tens
ions
of
cell
wal
l int
o pr
otop
lasm
tra
nsfe
r di
ssol
ved
subs
tanc
es b
etw
een
adja
cent
cel
l oc
cur
in p
ith
and
cort
ex o
f st
ems
and
root
s p
hoto
synt
hetic
tis
sues
of
leav
es f
lesh
of
succ
ulen
t fr
uits
endo
sper
m o
f se
eds
Das
hek
et a
l (1
971)
and
Off
ler
et a
l
(200
3)
Col
lenc
hym
a ce
llsLa
mel
lar
or p
late
col
lenc
hym
a w
ith t
hick
enin
gs o
n th
e ta
ngen
tial w
alls
Ang
ular
col
lenc
hym
a w
ith t
hick
enin
gs a
roun
d th
e ce
ll w
alls
Pres
ent
in a
eria
l por
tions
of
the
plan
t bo
dy
Vasc
ular
cel
lsEv
ert
(200
6)
Ph
loem
Siev
e ce
lls
Siev
e el
emen
ts
Com
pani
on c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
osse
ss n
umer
ous
plas
mod
esm
atal
con
nect
ions
Opa
rka
and
Turg
eon
(199
9)
Alb
umin
ous
cells
in
gym
nosp
erm
s
Abs
ence
of
star
ch c
ytop
lasm
ic b
ridge
s w
ith s
ieve
cel
ls d
ense
pro
topl
asm
abu
ndan
ce o
f
poly
som
es h
ighl
y co
nden
sed
euch
rom
atin
and
abu
ndan
t m
itoch
ondr
ia
Alo
si a
nd A
lfier
i (19
72) a
nd
Saut
er e
t al
(19
76)
X
ylem
Trac
heid
s
Vess
els
Long
tap
erin
g ce
ll w
ith li
gnifi
ed s
econ
dary
wal
l thi
cken
ings
can
hav
e pi
ts in
wal
ls d
evoi
d of
prot
opla
sm a
t m
atur
ity n
ot a
s sp
ecia
lized
as
vess
els
wid
espr
ead
Tyre
e an
d Zi
mm
erm
an (2
002)
Fuku
da (2
004)
and
Eve
rt (2
006)
(Con
tinue
d )
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Spec
ializ
ed c
ells
ndash H
ydat
hode
s
(mod
ified
par
ts o
f le
aves
and
leaf
tip
s or
mar
gins
)
Con
sist
of
term
inal
tra
chei
ds e
pith
em t
hin‐
wal
led
chlo
ropl
ast‐
defic
ient
cel
ls a
she
ath
with
wat
er p
ores
gut
tatio
n di
scha
rge
of li
quid
con
tain
ing
vario
us d
isso
lved
sol
utes
fro
m a
leaf
rsquos
inte
rior
Lers
ten
and
Cur
tis (1
996)
http
sw
ww
bio
sciu
texa
sed
u a
nd
Mae
da a
nd M
aeda
(198
8)
Latic
ifer
cells
Cel
ls o
r a
serie
s of
cel
ls w
hich
pro
duce
late
xFa
hn (1
990)
Pic
kard
(200
8) a
nd
Botw
ebu
wsp
Edu
Si
mpl
eSi
ngle
-cel
led
C
ompo
und
and
artic
ulat
ed
Uni
on o
f ce
lls c
ompo
und
in o
rigin
and
con
sist
of
long
itudi
nal c
hain
s of
cel
ls w
all s
epar
atin
g
cells
rem
ain
inta
ct c
an b
ecom
e pe
rfor
ated
or
entir
ely
rem
oved
Salt
glan
dsM
odifi
ed t
richo
mes
tw
o‐ce
lled
and
posi
tione
d fla
t on
the
sur
face
in r
ows
para
llel t
o th
e le
af
surf
ace
occ
ur in
Poa
ceae
Ever
t (2
006)
Tan
et
al (
2010
) O
ross
et a
l (1
985)
and
Tho
mso
n et
al
(198
8)
Cap
cel
l ndash la
rge
nucl
eus
and
expa
nded
cut
icle
Nai
doo
and
Nai
doo
(199
8)
Basa
l cel
l ndash n
umer
ous
and
larg
e ex
tens
ive
part
ition
ing
inva
gina
tions
of
plas
mal
emm
a
Nec
tarie
sFo
und
in n
ecta
rines
pro
duce
nec
tar
usua
lly a
t th
e ba
se o
f a
flow
erFa
hn (1
990)
Nic
olso
n an
d N
epi (
2005
)
and
Paiv
a (2
009)
Idio
blas
tsC
ryst
al‐c
onta
inin
g ce
llsLe
rste
n an
d H
orne
r (2
005)
Ex
ampl
e
Ra
phid
esPr
oduc
e ne
edle
‐sha
ped
crys
tals
Muc
ilage
cel
lO
ccur
in a
larg
e nu
mbe
r of
dic
ots
com
mon
in c
erta
in c
acti
slim
y m
ucila
ge p
reve
nts
evap
orat
ion
of w
ater
by
bind
ing
to w
ater
a p
aren
chym
a ce
ll w
hose
dic
tyos
omes
pro
duce
muc
ilage
as
in s
eed
coat
s c
ell w
alls
are
cel
lulo
sic
and
unlig
nifie
d
http
w
ww
sbs
ute
xas
edu
mas
uetl
web
lab
web
chap
9sec
reto
ry9
1‐2
htm
l
Wes
tern
et
al (
2000
) and
Ars
ovsk
ia
et a
l (2
010)
Oil
cells
Spec
ializ
ed c
ells
app
ear
like
larg
e pa
renc
hym
a ce
lls c
an o
ccur
in v
ascu
lar
and
grou
nd t
issu
es
of s
tem
and
leaf
cel
l wal
l has
thr
ee d
istin
ct la
yers
cav
ity is
for
med
aft
er t
he in
ner
wal
l lay
er
has
been
dep
osite
d
Rode
las
et a
l (2
008)
htt
pbr
ittan
ica
com
and
Ler
sten
et
al (
2006
)
Dru
ses
Sphe
rical
agg
rega
tes
of p
rism
atic
cry
stal
sLe
rste
n an
d H
orne
r (2
005)
Cel
ls in
non
‐ang
iosp
erm
s
Br
yoph
ytes
Gem
mae
One
to
man
y ce
llsht
tp
build
ingt
hepr
ide
com
fac
ulty
pgda
viso
nbr
yolo
gy_l
inks
htm
Hyd
roid
sW
ater
‐con
duct
ing
cells
http
w
ww
Bio
logy
‐onl
ine
org
Lept
oids
ndash P
terid
ophy
tes
Org
anic
com
poun
d‐co
nduc
ting
cells
spo
roge
nous
cel
ls p
rese
nt in
spo
rang
ia o
f so
ri
Tab
le 1
1 (
Con
tin
ued
)
An introduction to cells and their organelles 5
development is discussed in Fosket (1999) Moore and Clark (1995) Greenland
(2003) Leyser and Day (2003) and Rudall (2007)
What is the composition of cellsCertain plant components exhibit polar growth for example the tip growth of
pollen tubes (Hepler et al 2001) The tubes elongate via the fusion of Golgi‐
derived vesicles with the plasmalemma and subsequent deposition of the vesi-
clesrsquo contents into the cell wall (Taylor and Hepler 1997 Parton et al 2001 and
others as reviewed in Malho (2006a 2006b)) In 2007 Dalgic and Dane (2005)
published a diagram depicting the now known tube‐tip structural elements and
physiological processes that facilitate tube elongation The diagram represents a
Figure 12 Angiosperm shoot meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
Figure 13 Angiosperm root meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
6 Plant cells and their organelles
significant advance over the early studies of pollen tubes as it assigns function to
ultrastructural components for example signalling molecules the Rho family of
GTPases and phosphatidylinositol 45 bisphosphate appear to be localized in the
apical plasma membrane Besides pollen tubes root hairs exhibit polar growth
Cell organelles ndash an introduction
Organelles are required for plant growth development and function (Sadava
1993 Gillham 1994 Herrmann 1994 Agrawal 2011) These organelles
(Figure 17) are the loci for a myriad of physiological and biochemical processes
(Tobin 1992 Daniell and Chase 2004 ndash see individual chapters)
There are many diagrams of a generalized plant cell Some of these are available
at wwwexplorebiologycom httpwwwdaviddarlinginfoimagesplant_celljpg
Table 12 Meristems and their derivatives
Meristems Derivatives
Primary
Protoderm Epidermis
From tunica (Evert 2006)
Procambium (provascular) Primary xylem and phloem
From corpus (Evert 2006) Vascular cambium
Ground Ground tissue pith and cortex
Lateral
Vascular cambium
Fusiform initials Secondary xylem
Secondary phloem
Ray initials (Evert 2006) Ray cells
Cork cambium
Phellogen Replaces the epidermis when cork cambium initiates stem girth
increase composed of lsquoboxlikersquo cork cells which are dead at
maturity protoplasm secretes suberin some cork cells that are
loosely packed give rise to lenticels which function in gas exchange
between the air and the stemrsquos interior httpwwwBiology‐online
org Evert (2006) httpwwwvebrioSceincevunlenvirut
Periderm (Evert 2006)
Phelloderm Parenchyma cells produced on the inside by the cork cambium
Meristems are discussed by Steeves and Sussex (1989)
Table 13 Plant tissues
Tissue system
Meristematic Ground Vascular Dermal
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
vi Contents
4 The Golgi apparatus 61
D Davis TE Wilkop and Georgia Drakakaki
The Golgi apparatus 61
Plant Golgi introduction 66
Structure and organization 69
Golgi‐mediated vesicular trafficking 71
Plant Golgi‐dependent cellular processes 74
Imaging and visualization 76
Isolation and analysis 78
Golgi genetics and genomics 81
Significance 84
Acknowledgment 85
References 85
Further reading 87
5 Microbodies 88
Robert Donaldson
Introducing peroxisomes 88
Leaf peroxisomes 89
Peroxisomes in oil seeds and pollen 91
References 107
Further reading 109
6 Microtubules intermediate filaments and actin filaments 110
William V Dashek
Microtubules 110
Intermediate filaments 113
Actin filaments (microfilaments) 116
References 119
Further reading 124
7 The mitochondrion 125
Ray J Rose Terence W‐Y Tiew and William V Dashek
Structure and dynamics 125
The mitochondrial genome 128
Comparison of the mitochondrial genome with chloroplast and nuclear
genomes 131
The mitochondrial proteome and protein import 132
Respiratory metabolite transporters 133
The electron transport chain and oxidative phosphorylation 133
The alternative electron transfer chain in plant mitochondria 139
Plant mitochondria stress responses and programmed cell death 139
Other functions of plant mitochondria 140
References 144
Further reading 145
Contents vii
8 Nucleus 146
Yogesh Vikal and Dasmeet Kaur
Structural organization of the NE 147
Nuclear pores 152
The nucleolus 157
Chromatin and chromosomes 165
DNA structure 170
DNA replication 173
RNA structure function and synthesis 176
Nucleocytoplasmic transport nuclear import and nuclear export 183
The dynamics of NE biogenesis during mitosis 188
The dynamics of nuclear pore complex biogenesis 196
Cell cycle control 200
Summary 205
References 206
Further reading 207
9 Plant cell walls 209
James E Bidlack and William V Dashek
Introduction 209
Structure 209
Biosynthesis 216
Chemical composition 217
Biogenesis 222
Function 225
References 231
Further reading 238
10 Plastid structure and genomics 239
Gurbachan S Miglani
Plastid structure 239
Different forms of plastids 240
Plastid stromules 248
Chlorophyll biosynthesis 248
Plastid genomics 250
Sequenced plastomes 253
Promiscuous DNA 258
Plastid genome organization 260
Plastid gene organization expression and regulation 265
Systems biology approach in understanding chloroplast development 269
Chloroplast genetic engineering 284
Recent trends in chloroplast research 289
Summary 293
References 294
Further reading 299
viii Contents
11 Photosynthesis 300
J Kenneth Hoober
Introduction 300
Evolution of photosynthesis 301
Development of the chloroplast 310
Absorption of light energy 317
Generation of end products 324
Distribution of the photosystems in thylakoid membranes 329
Photoinhibition damage and repair of the PS II reaction center 332
Protection of PS II by carotenoids 332
Incorporation of carbon as CO2 into carbohydrate 334
End products of carbon assimilation 346
Conclusions for the reactions of photosynthesis 348
References 348
Further reading 350
12 Vacuoles and protein bodies 351
William V Dashek and Amy M Clore
Vacuoles 351
PBs and other protein storage compartments 359
References 365
Further reading 370
13 Systems biology in plant cells and their organelles 371
Rajdeep Kaur Grewal Saptarshi Sinha and Soumen Roy
Systems biologymdashldquoomicsrdquo 371
Genomics 373
Lipidomics 378
Metabolomics 380
Proteomics 382
Transcriptomics 384
Synthetic biology 386
Acknowledgments 388
References 389
Further reading 391
Appendix A 392
Appendix B 400
Appendix C 403
Index 407
ix
Milee AgarwalScientist
Pharmacology and Toxicology Department
BV Patel PERD Centre
Ahmedabad Gujarat India
James E BidlackProfessor of Biology and CURE‐STEM
Scholar
Department of Biology
University of Central Oklahoma
Edmond OK USA
Amy M CloreProfessor of Biology
Division of Natural Sciences
New College of Florida
Sarasota FL USA
William V DashekRetired Faculty
Adult Degree Program
Mary Baldwin College
Staunton VA USA
D DavisGraduate Student
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
P DesaiScientist
Cellular and Molecular Biology Department
BV Patel PERD Centre
Ahmedabad Gujarat India
Robert DonaldsonProfessor
Department of Biological Sciences
George Washington University
Washington DC USA
Georgia DrakakakiAssociate Professor
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
Rajdeep Kaur GrewalSenior Research Fellow
Department of Physics
Bose Institute
Kolkata India
J Kenneth HooberProfessor Emeritus
School of Life Sciences
Center for Photosynthesis
Arizona State University
Tempe AZ USA
Dasmeet KaurResearch Assistant
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
Gurbachan S MiglaniVisiting Professor
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
Contributors
x Contributors
Harish PadhVice-Chancellor
Sardar Patel University
Vallabh Vidyanagar Anand
Gujarat India
Ray J RoseEmeritus Professor
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Soumen RoyAssociate Professor
Department of Physics
Bose Institute
Kolkata India
Saptarshi SinhaSenior Research Fellow
Department of Physics
Bose Institute
Kolkata India
Terence W‐Y TiewGraduate Student
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Yogesh VikalSenior Geneticist
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
TE WilkopSenior Project Scientist
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
xi
Plant Cells and their Organelles is an advanced textbook to enhance the plant
biology studentrsquos knowledge of the structure and function of plant cells and their
organelles The book assumes that the student has had introductory courses in
plant science and chemistry The book emphasizes the research literature in
plant cell biology concerning cell and organellar structure However the litera-
ture from plant physiology molecular genetics and biochemistry has been
utilized to augment the discussions of cell and organellar function
Preface
xii
Dashek is grateful to Drs WG Rosen WF Millington and DTA Lamport for
training enabling a career in teaching and research in plant biology Dashek
appreciates the grant support of the USArsquos NIH NSF DOE and USDA Forest
Service Dashek thanks Ms Katherine Mumford Ms Retha Howard and
Ms Abigail M Johnson for technical assistance in the preparation of the
manuscript
Miglani wishes to record his appreciation for Dr Darshan S Brar Honorary
Adjunct Professor School of Agricultural Biotechnology Punjab Agricultural
University Ludhiana India for his valuable technical suggestions Miglani
thanks Dr (Mrs) Parveen Chhuneja Director School of Agricultural
Biotechnology Punjab Agricultural University Ludhiana India for motivat-
ing me to prepare this volume and the Punjab Agricultural University for
providing facilities for this work
We thank the Wiley editorial staff members for their attention to detail
Acknowledgments
1
Plant Cells and their Organelles First Edition Edited by William V Dashek and Gurbachan S Miglani
copy 2017 John Wiley amp Sons Ltd Published 2017 by John Wiley amp Sons Ltd
Cells
Parenchyma chlorenchyma collenchyma and sclerenchyma are the four main
plant cell types (Figure 11 Evert 2006) Meristematic cells which occur in
shoot and root meristems are parenchyma cells Chlorenchyma cells contain
chloroplasts and lack the cell wall thickening layers of collenchyma and scleren-
chyma Certain epidermal cells can be specialized as stomata that are important
in gas exchange (Bergmann and Sack 2007) The diverse cell types (Zhang et al
2001 Yang and Liu 2007) are shown in Table 11 Photomicrographs of certain of
these cell types can be found in Evert (2006) Fahn (1990) Beck (2005) Rudall
(2007) Gunning (2009) MacAdam (2009) Wayne (2009) Beck (2009) Assmann
and Liu (2014) and Noguchi et al (2014)
How do cells ariseCells arise by cell divisions (see Chapter 8 for mitosis and meiosis) in shoot and
root (Figures 12 and 13) meristems (Table 12 Lyndon 1998 McManus and Veit
2001 Murray 2012) The shoot apex is characterized by a tunicandashcorpus organiza-
tion (Steeves and Sussex 1989) The tunica gives rise to the protoderm and its
derivative the epidermis In contrast the corpus provides the procambium which
yields the primary xylem and phloem In addition the ground tissue derives from
the corpus originating the pith and cortex Following divisions cells can differenti-
ate into tissues (Table 13) and organs of the mature plant body (Leyser and Day
2003 Sachs 2005 Dashek and Harrison 2006) The leaf primodium arises on the
apex (Micol and Hake 2003) The mature angiosperm leaf consists of palisade cells
and spongy mesophyll cells sandwiched between the upper and the lower epider-
mis (Figure 14) The epidermis possesses guard cells with associated stomata that
function in gas exchange KNOX genes affect meristem maintenance and suitable
patterning of organ formation (Hake et al 2004) In dissected leaves KNOX genes
are expressed in leaf primordia (Hake et al 2004) Hake et al (2004) suggest that
An introduction to cells and their organellesWilliam V DashekRetired Faculty Adult Degree Program Mary Baldwin College Staunton VA USA
CHapter 1
2 Plant cells and their organelles
KNOX genes may be important in the diversity of leaf form Extensive discussions
of leaf development occur in Sinha (1999) Micol and Hake (2003) and Efroni
et al (2010) Under appropriate stimuli the vegetative apex can be converted to a
floral apex (Figure 15) Photoperiod (Mazumdar 2013) such as short days and
long days and combinations of the two is one such stimulus (Glover 2007
Kinmonth‐Schultz et al 2013) This induction results in the production of florigen
(Turck et al 2008) the flowering hormone (Zeevaart 2006) While early reports
suggest that florigen is an mRNA species (Huang et al 2005) a more recent inves-
tigation indicates that florigen is a protein complex (Yang et al 2007 Taoka et al
2013) Taoka et al state that florigen protein is encoded by the gene Flowering
Locus T in Arabidopsis species (Shresth et al 2014) It is believed that florigen is
induced in leaves and that it moves through the phloem to the shoot apex Plant
hormones (see Appendix A) can influence floral development (Howell 1998)
Gibberellins (Blaacutezquez et al 1998) auxins and jasmonic acid can affect petal
development In contrast auxin can influence gynoecium development The ABC
model has been proposed for regulating the development of floral parts (Soltis
et al 2006) The A gene expression is responsible for sepals while the petals are
the result of co‐expression of A and B genes The B and C genes are responsible for
stamen development and carpels require C genes In certain plants vernalization
(low temperature) can induce flowering in certain plants (Kemi et al 2013)
A diagram of the mature angiosperm plant body is presented in Figure 16 Plant
Primary phloem bres
CO
par
A
Epidermis
Cortex
Phloem
Vascularcambium
Secondaryxylem
Figure 11 Plant cell types Left parenchyma (par) and collenchyma (co) Right
sclerenchyma Source Evert (2006) Reproduced with permission of John Wiley amp Sons
Tab
le 1
1 P
lan
t ce
ll t
ypes
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Epid
erm
al c
ells
Uns
peci
aliz
ed c
ells
one
laye
r of
cel
ls in
thi
ckne
ss o
uter
cov
erin
g of
var
ious
pla
nt p
arts
varia
ble
in s
hape
but
oft
en t
abul
ar
Ever
t (2
006)
Ex
ampl
es
G
uard
cel
lsSp
ecia
lized
epi
derm
al c
ells
cre
scen
t sh
aped
con
tain
chl
orop
last
s f
orm
def
ines
sto
mat
al p
ore
Will
e an
d Lu
cas
(198
4)
Su
bsid
iary
cel
lsC
ells
whi
ch s
ubte
nd t
he s
tom
atal
gua
rd c
ells
http
an
ubis
ru
acz
aM
ain
AN
ATO
MY
gua
rdce
llsh
tml
Tr
icho
mes
An
outg
row
th o
f an
epi
derm
al c
ell
can
be u
nice
llula
r or
mul
ticel
lula
rC
allo
w (2
000)
Pare
nchy
ma
cells
Isod
iam
etric
thi
n‐w
alle
d pr
imar
y ce
ll w
all
in s
ome
inst
ance
s m
ay h
ave
seco
ndar
y w
alls
not
high
ly d
iffer
entia
ted
fun
ctio
n in
pho
tosy
nthe
sis
sec
retio
n o
rgan
ic n
utrie
nt a
nd w
ater
stor
age
reg
ener
atio
n in
wou
nd h
ealin
g
Ever
t (2
006)
and
Saj
eva
and
Mau
seth
(199
1)
Ex
ampl
es
Tr
ansf
er c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
lasm
alem
ma
grea
tly e
xpan
ded
irre
gula
r ex
tens
ions
of
cell
wal
l int
o pr
otop
lasm
tra
nsfe
r di
ssol
ved
subs
tanc
es b
etw
een
adja
cent
cel
l oc
cur
in p
ith
and
cort
ex o
f st
ems
and
root
s p
hoto
synt
hetic
tis
sues
of
leav
es f
lesh
of
succ
ulen
t fr
uits
endo
sper
m o
f se
eds
Das
hek
et a
l (1
971)
and
Off
ler
et a
l
(200
3)
Col
lenc
hym
a ce
llsLa
mel
lar
or p
late
col
lenc
hym
a w
ith t
hick
enin
gs o
n th
e ta
ngen
tial w
alls
Ang
ular
col
lenc
hym
a w
ith t
hick
enin
gs a
roun
d th
e ce
ll w
alls
Pres
ent
in a
eria
l por
tions
of
the
plan
t bo
dy
Vasc
ular
cel
lsEv
ert
(200
6)
Ph
loem
Siev
e ce
lls
Siev
e el
emen
ts
Com
pani
on c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
osse
ss n
umer
ous
plas
mod
esm
atal
con
nect
ions
Opa
rka
and
Turg
eon
(199
9)
Alb
umin
ous
cells
in
gym
nosp
erm
s
Abs
ence
of
star
ch c
ytop
lasm
ic b
ridge
s w
ith s
ieve
cel
ls d
ense
pro
topl
asm
abu
ndan
ce o
f
poly
som
es h
ighl
y co
nden
sed
euch
rom
atin
and
abu
ndan
t m
itoch
ondr
ia
Alo
si a
nd A
lfier
i (19
72) a
nd
Saut
er e
t al
(19
76)
X
ylem
Trac
heid
s
Vess
els
Long
tap
erin
g ce
ll w
ith li
gnifi
ed s
econ
dary
wal
l thi
cken
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Cel
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Ref
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and
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tis (1
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mso
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Cap
cel
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Basa
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Tab
le 1
1 (
Con
tin
ued
)
An introduction to cells and their organelles 5
development is discussed in Fosket (1999) Moore and Clark (1995) Greenland
(2003) Leyser and Day (2003) and Rudall (2007)
What is the composition of cellsCertain plant components exhibit polar growth for example the tip growth of
pollen tubes (Hepler et al 2001) The tubes elongate via the fusion of Golgi‐
derived vesicles with the plasmalemma and subsequent deposition of the vesi-
clesrsquo contents into the cell wall (Taylor and Hepler 1997 Parton et al 2001 and
others as reviewed in Malho (2006a 2006b)) In 2007 Dalgic and Dane (2005)
published a diagram depicting the now known tube‐tip structural elements and
physiological processes that facilitate tube elongation The diagram represents a
Figure 12 Angiosperm shoot meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
Figure 13 Angiosperm root meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
6 Plant cells and their organelles
significant advance over the early studies of pollen tubes as it assigns function to
ultrastructural components for example signalling molecules the Rho family of
GTPases and phosphatidylinositol 45 bisphosphate appear to be localized in the
apical plasma membrane Besides pollen tubes root hairs exhibit polar growth
Cell organelles ndash an introduction
Organelles are required for plant growth development and function (Sadava
1993 Gillham 1994 Herrmann 1994 Agrawal 2011) These organelles
(Figure 17) are the loci for a myriad of physiological and biochemical processes
(Tobin 1992 Daniell and Chase 2004 ndash see individual chapters)
There are many diagrams of a generalized plant cell Some of these are available
at wwwexplorebiologycom httpwwwdaviddarlinginfoimagesplant_celljpg
Table 12 Meristems and their derivatives
Meristems Derivatives
Primary
Protoderm Epidermis
From tunica (Evert 2006)
Procambium (provascular) Primary xylem and phloem
From corpus (Evert 2006) Vascular cambium
Ground Ground tissue pith and cortex
Lateral
Vascular cambium
Fusiform initials Secondary xylem
Secondary phloem
Ray initials (Evert 2006) Ray cells
Cork cambium
Phellogen Replaces the epidermis when cork cambium initiates stem girth
increase composed of lsquoboxlikersquo cork cells which are dead at
maturity protoplasm secretes suberin some cork cells that are
loosely packed give rise to lenticels which function in gas exchange
between the air and the stemrsquos interior httpwwwBiology‐online
org Evert (2006) httpwwwvebrioSceincevunlenvirut
Periderm (Evert 2006)
Phelloderm Parenchyma cells produced on the inside by the cork cambium
Meristems are discussed by Steeves and Sussex (1989)
Table 13 Plant tissues
Tissue system
Meristematic Ground Vascular Dermal
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
Contents vii
8 Nucleus 146
Yogesh Vikal and Dasmeet Kaur
Structural organization of the NE 147
Nuclear pores 152
The nucleolus 157
Chromatin and chromosomes 165
DNA structure 170
DNA replication 173
RNA structure function and synthesis 176
Nucleocytoplasmic transport nuclear import and nuclear export 183
The dynamics of NE biogenesis during mitosis 188
The dynamics of nuclear pore complex biogenesis 196
Cell cycle control 200
Summary 205
References 206
Further reading 207
9 Plant cell walls 209
James E Bidlack and William V Dashek
Introduction 209
Structure 209
Biosynthesis 216
Chemical composition 217
Biogenesis 222
Function 225
References 231
Further reading 238
10 Plastid structure and genomics 239
Gurbachan S Miglani
Plastid structure 239
Different forms of plastids 240
Plastid stromules 248
Chlorophyll biosynthesis 248
Plastid genomics 250
Sequenced plastomes 253
Promiscuous DNA 258
Plastid genome organization 260
Plastid gene organization expression and regulation 265
Systems biology approach in understanding chloroplast development 269
Chloroplast genetic engineering 284
Recent trends in chloroplast research 289
Summary 293
References 294
Further reading 299
viii Contents
11 Photosynthesis 300
J Kenneth Hoober
Introduction 300
Evolution of photosynthesis 301
Development of the chloroplast 310
Absorption of light energy 317
Generation of end products 324
Distribution of the photosystems in thylakoid membranes 329
Photoinhibition damage and repair of the PS II reaction center 332
Protection of PS II by carotenoids 332
Incorporation of carbon as CO2 into carbohydrate 334
End products of carbon assimilation 346
Conclusions for the reactions of photosynthesis 348
References 348
Further reading 350
12 Vacuoles and protein bodies 351
William V Dashek and Amy M Clore
Vacuoles 351
PBs and other protein storage compartments 359
References 365
Further reading 370
13 Systems biology in plant cells and their organelles 371
Rajdeep Kaur Grewal Saptarshi Sinha and Soumen Roy
Systems biologymdashldquoomicsrdquo 371
Genomics 373
Lipidomics 378
Metabolomics 380
Proteomics 382
Transcriptomics 384
Synthetic biology 386
Acknowledgments 388
References 389
Further reading 391
Appendix A 392
Appendix B 400
Appendix C 403
Index 407
ix
Milee AgarwalScientist
Pharmacology and Toxicology Department
BV Patel PERD Centre
Ahmedabad Gujarat India
James E BidlackProfessor of Biology and CURE‐STEM
Scholar
Department of Biology
University of Central Oklahoma
Edmond OK USA
Amy M CloreProfessor of Biology
Division of Natural Sciences
New College of Florida
Sarasota FL USA
William V DashekRetired Faculty
Adult Degree Program
Mary Baldwin College
Staunton VA USA
D DavisGraduate Student
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
P DesaiScientist
Cellular and Molecular Biology Department
BV Patel PERD Centre
Ahmedabad Gujarat India
Robert DonaldsonProfessor
Department of Biological Sciences
George Washington University
Washington DC USA
Georgia DrakakakiAssociate Professor
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
Rajdeep Kaur GrewalSenior Research Fellow
Department of Physics
Bose Institute
Kolkata India
J Kenneth HooberProfessor Emeritus
School of Life Sciences
Center for Photosynthesis
Arizona State University
Tempe AZ USA
Dasmeet KaurResearch Assistant
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
Gurbachan S MiglaniVisiting Professor
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
Contributors
x Contributors
Harish PadhVice-Chancellor
Sardar Patel University
Vallabh Vidyanagar Anand
Gujarat India
Ray J RoseEmeritus Professor
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Soumen RoyAssociate Professor
Department of Physics
Bose Institute
Kolkata India
Saptarshi SinhaSenior Research Fellow
Department of Physics
Bose Institute
Kolkata India
Terence W‐Y TiewGraduate Student
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Yogesh VikalSenior Geneticist
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
TE WilkopSenior Project Scientist
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
xi
Plant Cells and their Organelles is an advanced textbook to enhance the plant
biology studentrsquos knowledge of the structure and function of plant cells and their
organelles The book assumes that the student has had introductory courses in
plant science and chemistry The book emphasizes the research literature in
plant cell biology concerning cell and organellar structure However the litera-
ture from plant physiology molecular genetics and biochemistry has been
utilized to augment the discussions of cell and organellar function
Preface
xii
Dashek is grateful to Drs WG Rosen WF Millington and DTA Lamport for
training enabling a career in teaching and research in plant biology Dashek
appreciates the grant support of the USArsquos NIH NSF DOE and USDA Forest
Service Dashek thanks Ms Katherine Mumford Ms Retha Howard and
Ms Abigail M Johnson for technical assistance in the preparation of the
manuscript
Miglani wishes to record his appreciation for Dr Darshan S Brar Honorary
Adjunct Professor School of Agricultural Biotechnology Punjab Agricultural
University Ludhiana India for his valuable technical suggestions Miglani
thanks Dr (Mrs) Parveen Chhuneja Director School of Agricultural
Biotechnology Punjab Agricultural University Ludhiana India for motivat-
ing me to prepare this volume and the Punjab Agricultural University for
providing facilities for this work
We thank the Wiley editorial staff members for their attention to detail
Acknowledgments
1
Plant Cells and their Organelles First Edition Edited by William V Dashek and Gurbachan S Miglani
copy 2017 John Wiley amp Sons Ltd Published 2017 by John Wiley amp Sons Ltd
Cells
Parenchyma chlorenchyma collenchyma and sclerenchyma are the four main
plant cell types (Figure 11 Evert 2006) Meristematic cells which occur in
shoot and root meristems are parenchyma cells Chlorenchyma cells contain
chloroplasts and lack the cell wall thickening layers of collenchyma and scleren-
chyma Certain epidermal cells can be specialized as stomata that are important
in gas exchange (Bergmann and Sack 2007) The diverse cell types (Zhang et al
2001 Yang and Liu 2007) are shown in Table 11 Photomicrographs of certain of
these cell types can be found in Evert (2006) Fahn (1990) Beck (2005) Rudall
(2007) Gunning (2009) MacAdam (2009) Wayne (2009) Beck (2009) Assmann
and Liu (2014) and Noguchi et al (2014)
How do cells ariseCells arise by cell divisions (see Chapter 8 for mitosis and meiosis) in shoot and
root (Figures 12 and 13) meristems (Table 12 Lyndon 1998 McManus and Veit
2001 Murray 2012) The shoot apex is characterized by a tunicandashcorpus organiza-
tion (Steeves and Sussex 1989) The tunica gives rise to the protoderm and its
derivative the epidermis In contrast the corpus provides the procambium which
yields the primary xylem and phloem In addition the ground tissue derives from
the corpus originating the pith and cortex Following divisions cells can differenti-
ate into tissues (Table 13) and organs of the mature plant body (Leyser and Day
2003 Sachs 2005 Dashek and Harrison 2006) The leaf primodium arises on the
apex (Micol and Hake 2003) The mature angiosperm leaf consists of palisade cells
and spongy mesophyll cells sandwiched between the upper and the lower epider-
mis (Figure 14) The epidermis possesses guard cells with associated stomata that
function in gas exchange KNOX genes affect meristem maintenance and suitable
patterning of organ formation (Hake et al 2004) In dissected leaves KNOX genes
are expressed in leaf primordia (Hake et al 2004) Hake et al (2004) suggest that
An introduction to cells and their organellesWilliam V DashekRetired Faculty Adult Degree Program Mary Baldwin College Staunton VA USA
CHapter 1
2 Plant cells and their organelles
KNOX genes may be important in the diversity of leaf form Extensive discussions
of leaf development occur in Sinha (1999) Micol and Hake (2003) and Efroni
et al (2010) Under appropriate stimuli the vegetative apex can be converted to a
floral apex (Figure 15) Photoperiod (Mazumdar 2013) such as short days and
long days and combinations of the two is one such stimulus (Glover 2007
Kinmonth‐Schultz et al 2013) This induction results in the production of florigen
(Turck et al 2008) the flowering hormone (Zeevaart 2006) While early reports
suggest that florigen is an mRNA species (Huang et al 2005) a more recent inves-
tigation indicates that florigen is a protein complex (Yang et al 2007 Taoka et al
2013) Taoka et al state that florigen protein is encoded by the gene Flowering
Locus T in Arabidopsis species (Shresth et al 2014) It is believed that florigen is
induced in leaves and that it moves through the phloem to the shoot apex Plant
hormones (see Appendix A) can influence floral development (Howell 1998)
Gibberellins (Blaacutezquez et al 1998) auxins and jasmonic acid can affect petal
development In contrast auxin can influence gynoecium development The ABC
model has been proposed for regulating the development of floral parts (Soltis
et al 2006) The A gene expression is responsible for sepals while the petals are
the result of co‐expression of A and B genes The B and C genes are responsible for
stamen development and carpels require C genes In certain plants vernalization
(low temperature) can induce flowering in certain plants (Kemi et al 2013)
A diagram of the mature angiosperm plant body is presented in Figure 16 Plant
Primary phloem bres
CO
par
A
Epidermis
Cortex
Phloem
Vascularcambium
Secondaryxylem
Figure 11 Plant cell types Left parenchyma (par) and collenchyma (co) Right
sclerenchyma Source Evert (2006) Reproduced with permission of John Wiley amp Sons
Tab
le 1
1 P
lan
t ce
ll t
ypes
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Epid
erm
al c
ells
Uns
peci
aliz
ed c
ells
one
laye
r of
cel
ls in
thi
ckne
ss o
uter
cov
erin
g of
var
ious
pla
nt p
arts
varia
ble
in s
hape
but
oft
en t
abul
ar
Ever
t (2
006)
Ex
ampl
es
G
uard
cel
lsSp
ecia
lized
epi
derm
al c
ells
cre
scen
t sh
aped
con
tain
chl
orop
last
s f
orm
def
ines
sto
mat
al p
ore
Will
e an
d Lu
cas
(198
4)
Su
bsid
iary
cel
lsC
ells
whi
ch s
ubte
nd t
he s
tom
atal
gua
rd c
ells
http
an
ubis
ru
acz
aM
ain
AN
ATO
MY
gua
rdce
llsh
tml
Tr
icho
mes
An
outg
row
th o
f an
epi
derm
al c
ell
can
be u
nice
llula
r or
mul
ticel
lula
rC
allo
w (2
000)
Pare
nchy
ma
cells
Isod
iam
etric
thi
n‐w
alle
d pr
imar
y ce
ll w
all
in s
ome
inst
ance
s m
ay h
ave
seco
ndar
y w
alls
not
high
ly d
iffer
entia
ted
fun
ctio
n in
pho
tosy
nthe
sis
sec
retio
n o
rgan
ic n
utrie
nt a
nd w
ater
stor
age
reg
ener
atio
n in
wou
nd h
ealin
g
Ever
t (2
006)
and
Saj
eva
and
Mau
seth
(199
1)
Ex
ampl
es
Tr
ansf
er c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
lasm
alem
ma
grea
tly e
xpan
ded
irre
gula
r ex
tens
ions
of
cell
wal
l int
o pr
otop
lasm
tra
nsfe
r di
ssol
ved
subs
tanc
es b
etw
een
adja
cent
cel
l oc
cur
in p
ith
and
cort
ex o
f st
ems
and
root
s p
hoto
synt
hetic
tis
sues
of
leav
es f
lesh
of
succ
ulen
t fr
uits
endo
sper
m o
f se
eds
Das
hek
et a
l (1
971)
and
Off
ler
et a
l
(200
3)
Col
lenc
hym
a ce
llsLa
mel
lar
or p
late
col
lenc
hym
a w
ith t
hick
enin
gs o
n th
e ta
ngen
tial w
alls
Ang
ular
col
lenc
hym
a w
ith t
hick
enin
gs a
roun
d th
e ce
ll w
alls
Pres
ent
in a
eria
l por
tions
of
the
plan
t bo
dy
Vasc
ular
cel
lsEv
ert
(200
6)
Ph
loem
Siev
e ce
lls
Siev
e el
emen
ts
Com
pani
on c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
osse
ss n
umer
ous
plas
mod
esm
atal
con
nect
ions
Opa
rka
and
Turg
eon
(199
9)
Alb
umin
ous
cells
in
gym
nosp
erm
s
Abs
ence
of
star
ch c
ytop
lasm
ic b
ridge
s w
ith s
ieve
cel
ls d
ense
pro
topl
asm
abu
ndan
ce o
f
poly
som
es h
ighl
y co
nden
sed
euch
rom
atin
and
abu
ndan
t m
itoch
ondr
ia
Alo
si a
nd A
lfier
i (19
72) a
nd
Saut
er e
t al
(19
76)
X
ylem
Trac
heid
s
Vess
els
Long
tap
erin
g ce
ll w
ith li
gnifi
ed s
econ
dary
wal
l thi
cken
ings
can
hav
e pi
ts in
wal
ls d
evoi
d of
prot
opla
sm a
t m
atur
ity n
ot a
s sp
ecia
lized
as
vess
els
wid
espr
ead
Tyre
e an
d Zi
mm
erm
an (2
002)
Fuku
da (2
004)
and
Eve
rt (2
006)
(Con
tinue
d )
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Spec
ializ
ed c
ells
ndash H
ydat
hode
s
(mod
ified
par
ts o
f le
aves
and
leaf
tip
s or
mar
gins
)
Con
sist
of
term
inal
tra
chei
ds e
pith
em t
hin‐
wal
led
chlo
ropl
ast‐
defic
ient
cel
ls a
she
ath
with
wat
er p
ores
gut
tatio
n di
scha
rge
of li
quid
con
tain
ing
vario
us d
isso
lved
sol
utes
fro
m a
leaf
rsquos
inte
rior
Lers
ten
and
Cur
tis (1
996)
http
sw
ww
bio
sciu
texa
sed
u a
nd
Mae
da a
nd M
aeda
(198
8)
Latic
ifer
cells
Cel
ls o
r a
serie
s of
cel
ls w
hich
pro
duce
late
xFa
hn (1
990)
Pic
kard
(200
8) a
nd
Botw
ebu
wsp
Edu
Si
mpl
eSi
ngle
-cel
led
C
ompo
und
and
artic
ulat
ed
Uni
on o
f ce
lls c
ompo
und
in o
rigin
and
con
sist
of
long
itudi
nal c
hain
s of
cel
ls w
all s
epar
atin
g
cells
rem
ain
inta
ct c
an b
ecom
e pe
rfor
ated
or
entir
ely
rem
oved
Salt
glan
dsM
odifi
ed t
richo
mes
tw
o‐ce
lled
and
posi
tione
d fla
t on
the
sur
face
in r
ows
para
llel t
o th
e le
af
surf
ace
occ
ur in
Poa
ceae
Ever
t (2
006)
Tan
et
al (
2010
) O
ross
et a
l (1
985)
and
Tho
mso
n et
al
(198
8)
Cap
cel
l ndash la
rge
nucl
eus
and
expa
nded
cut
icle
Nai
doo
and
Nai
doo
(199
8)
Basa
l cel
l ndash n
umer
ous
and
larg
e ex
tens
ive
part
ition
ing
inva
gina
tions
of
plas
mal
emm
a
Nec
tarie
sFo
und
in n
ecta
rines
pro
duce
nec
tar
usua
lly a
t th
e ba
se o
f a
flow
erFa
hn (1
990)
Nic
olso
n an
d N
epi (
2005
)
and
Paiv
a (2
009)
Idio
blas
tsC
ryst
al‐c
onta
inin
g ce
llsLe
rste
n an
d H
orne
r (2
005)
Ex
ampl
e
Ra
phid
esPr
oduc
e ne
edle
‐sha
ped
crys
tals
Muc
ilage
cel
lO
ccur
in a
larg
e nu
mbe
r of
dic
ots
com
mon
in c
erta
in c
acti
slim
y m
ucila
ge p
reve
nts
evap
orat
ion
of w
ater
by
bind
ing
to w
ater
a p
aren
chym
a ce
ll w
hose
dic
tyos
omes
pro
duce
muc
ilage
as
in s
eed
coat
s c
ell w
alls
are
cel
lulo
sic
and
unlig
nifie
d
http
w
ww
sbs
ute
xas
edu
mas
uetl
web
lab
web
chap
9sec
reto
ry9
1‐2
htm
l
Wes
tern
et
al (
2000
) and
Ars
ovsk
ia
et a
l (2
010)
Oil
cells
Spec
ializ
ed c
ells
app
ear
like
larg
e pa
renc
hym
a ce
lls c
an o
ccur
in v
ascu
lar
and
grou
nd t
issu
es
of s
tem
and
leaf
cel
l wal
l has
thr
ee d
istin
ct la
yers
cav
ity is
for
med
aft
er t
he in
ner
wal
l lay
er
has
been
dep
osite
d
Rode
las
et a
l (2
008)
htt
pbr
ittan
ica
com
and
Ler
sten
et
al (
2006
)
Dru
ses
Sphe
rical
agg
rega
tes
of p
rism
atic
cry
stal
sLe
rste
n an
d H
orne
r (2
005)
Cel
ls in
non
‐ang
iosp
erm
s
Br
yoph
ytes
Gem
mae
One
to
man
y ce
llsht
tp
build
ingt
hepr
ide
com
fac
ulty
pgda
viso
nbr
yolo
gy_l
inks
htm
Hyd
roid
sW
ater
‐con
duct
ing
cells
http
w
ww
Bio
logy
‐onl
ine
org
Lept
oids
ndash P
terid
ophy
tes
Org
anic
com
poun
d‐co
nduc
ting
cells
spo
roge
nous
cel
ls p
rese
nt in
spo
rang
ia o
f so
ri
Tab
le 1
1 (
Con
tin
ued
)
An introduction to cells and their organelles 5
development is discussed in Fosket (1999) Moore and Clark (1995) Greenland
(2003) Leyser and Day (2003) and Rudall (2007)
What is the composition of cellsCertain plant components exhibit polar growth for example the tip growth of
pollen tubes (Hepler et al 2001) The tubes elongate via the fusion of Golgi‐
derived vesicles with the plasmalemma and subsequent deposition of the vesi-
clesrsquo contents into the cell wall (Taylor and Hepler 1997 Parton et al 2001 and
others as reviewed in Malho (2006a 2006b)) In 2007 Dalgic and Dane (2005)
published a diagram depicting the now known tube‐tip structural elements and
physiological processes that facilitate tube elongation The diagram represents a
Figure 12 Angiosperm shoot meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
Figure 13 Angiosperm root meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
6 Plant cells and their organelles
significant advance over the early studies of pollen tubes as it assigns function to
ultrastructural components for example signalling molecules the Rho family of
GTPases and phosphatidylinositol 45 bisphosphate appear to be localized in the
apical plasma membrane Besides pollen tubes root hairs exhibit polar growth
Cell organelles ndash an introduction
Organelles are required for plant growth development and function (Sadava
1993 Gillham 1994 Herrmann 1994 Agrawal 2011) These organelles
(Figure 17) are the loci for a myriad of physiological and biochemical processes
(Tobin 1992 Daniell and Chase 2004 ndash see individual chapters)
There are many diagrams of a generalized plant cell Some of these are available
at wwwexplorebiologycom httpwwwdaviddarlinginfoimagesplant_celljpg
Table 12 Meristems and their derivatives
Meristems Derivatives
Primary
Protoderm Epidermis
From tunica (Evert 2006)
Procambium (provascular) Primary xylem and phloem
From corpus (Evert 2006) Vascular cambium
Ground Ground tissue pith and cortex
Lateral
Vascular cambium
Fusiform initials Secondary xylem
Secondary phloem
Ray initials (Evert 2006) Ray cells
Cork cambium
Phellogen Replaces the epidermis when cork cambium initiates stem girth
increase composed of lsquoboxlikersquo cork cells which are dead at
maturity protoplasm secretes suberin some cork cells that are
loosely packed give rise to lenticels which function in gas exchange
between the air and the stemrsquos interior httpwwwBiology‐online
org Evert (2006) httpwwwvebrioSceincevunlenvirut
Periderm (Evert 2006)
Phelloderm Parenchyma cells produced on the inside by the cork cambium
Meristems are discussed by Steeves and Sussex (1989)
Table 13 Plant tissues
Tissue system
Meristematic Ground Vascular Dermal
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
viii Contents
11 Photosynthesis 300
J Kenneth Hoober
Introduction 300
Evolution of photosynthesis 301
Development of the chloroplast 310
Absorption of light energy 317
Generation of end products 324
Distribution of the photosystems in thylakoid membranes 329
Photoinhibition damage and repair of the PS II reaction center 332
Protection of PS II by carotenoids 332
Incorporation of carbon as CO2 into carbohydrate 334
End products of carbon assimilation 346
Conclusions for the reactions of photosynthesis 348
References 348
Further reading 350
12 Vacuoles and protein bodies 351
William V Dashek and Amy M Clore
Vacuoles 351
PBs and other protein storage compartments 359
References 365
Further reading 370
13 Systems biology in plant cells and their organelles 371
Rajdeep Kaur Grewal Saptarshi Sinha and Soumen Roy
Systems biologymdashldquoomicsrdquo 371
Genomics 373
Lipidomics 378
Metabolomics 380
Proteomics 382
Transcriptomics 384
Synthetic biology 386
Acknowledgments 388
References 389
Further reading 391
Appendix A 392
Appendix B 400
Appendix C 403
Index 407
ix
Milee AgarwalScientist
Pharmacology and Toxicology Department
BV Patel PERD Centre
Ahmedabad Gujarat India
James E BidlackProfessor of Biology and CURE‐STEM
Scholar
Department of Biology
University of Central Oklahoma
Edmond OK USA
Amy M CloreProfessor of Biology
Division of Natural Sciences
New College of Florida
Sarasota FL USA
William V DashekRetired Faculty
Adult Degree Program
Mary Baldwin College
Staunton VA USA
D DavisGraduate Student
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
P DesaiScientist
Cellular and Molecular Biology Department
BV Patel PERD Centre
Ahmedabad Gujarat India
Robert DonaldsonProfessor
Department of Biological Sciences
George Washington University
Washington DC USA
Georgia DrakakakiAssociate Professor
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
Rajdeep Kaur GrewalSenior Research Fellow
Department of Physics
Bose Institute
Kolkata India
J Kenneth HooberProfessor Emeritus
School of Life Sciences
Center for Photosynthesis
Arizona State University
Tempe AZ USA
Dasmeet KaurResearch Assistant
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
Gurbachan S MiglaniVisiting Professor
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
Contributors
x Contributors
Harish PadhVice-Chancellor
Sardar Patel University
Vallabh Vidyanagar Anand
Gujarat India
Ray J RoseEmeritus Professor
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Soumen RoyAssociate Professor
Department of Physics
Bose Institute
Kolkata India
Saptarshi SinhaSenior Research Fellow
Department of Physics
Bose Institute
Kolkata India
Terence W‐Y TiewGraduate Student
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Yogesh VikalSenior Geneticist
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
TE WilkopSenior Project Scientist
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
xi
Plant Cells and their Organelles is an advanced textbook to enhance the plant
biology studentrsquos knowledge of the structure and function of plant cells and their
organelles The book assumes that the student has had introductory courses in
plant science and chemistry The book emphasizes the research literature in
plant cell biology concerning cell and organellar structure However the litera-
ture from plant physiology molecular genetics and biochemistry has been
utilized to augment the discussions of cell and organellar function
Preface
xii
Dashek is grateful to Drs WG Rosen WF Millington and DTA Lamport for
training enabling a career in teaching and research in plant biology Dashek
appreciates the grant support of the USArsquos NIH NSF DOE and USDA Forest
Service Dashek thanks Ms Katherine Mumford Ms Retha Howard and
Ms Abigail M Johnson for technical assistance in the preparation of the
manuscript
Miglani wishes to record his appreciation for Dr Darshan S Brar Honorary
Adjunct Professor School of Agricultural Biotechnology Punjab Agricultural
University Ludhiana India for his valuable technical suggestions Miglani
thanks Dr (Mrs) Parveen Chhuneja Director School of Agricultural
Biotechnology Punjab Agricultural University Ludhiana India for motivat-
ing me to prepare this volume and the Punjab Agricultural University for
providing facilities for this work
We thank the Wiley editorial staff members for their attention to detail
Acknowledgments
1
Plant Cells and their Organelles First Edition Edited by William V Dashek and Gurbachan S Miglani
copy 2017 John Wiley amp Sons Ltd Published 2017 by John Wiley amp Sons Ltd
Cells
Parenchyma chlorenchyma collenchyma and sclerenchyma are the four main
plant cell types (Figure 11 Evert 2006) Meristematic cells which occur in
shoot and root meristems are parenchyma cells Chlorenchyma cells contain
chloroplasts and lack the cell wall thickening layers of collenchyma and scleren-
chyma Certain epidermal cells can be specialized as stomata that are important
in gas exchange (Bergmann and Sack 2007) The diverse cell types (Zhang et al
2001 Yang and Liu 2007) are shown in Table 11 Photomicrographs of certain of
these cell types can be found in Evert (2006) Fahn (1990) Beck (2005) Rudall
(2007) Gunning (2009) MacAdam (2009) Wayne (2009) Beck (2009) Assmann
and Liu (2014) and Noguchi et al (2014)
How do cells ariseCells arise by cell divisions (see Chapter 8 for mitosis and meiosis) in shoot and
root (Figures 12 and 13) meristems (Table 12 Lyndon 1998 McManus and Veit
2001 Murray 2012) The shoot apex is characterized by a tunicandashcorpus organiza-
tion (Steeves and Sussex 1989) The tunica gives rise to the protoderm and its
derivative the epidermis In contrast the corpus provides the procambium which
yields the primary xylem and phloem In addition the ground tissue derives from
the corpus originating the pith and cortex Following divisions cells can differenti-
ate into tissues (Table 13) and organs of the mature plant body (Leyser and Day
2003 Sachs 2005 Dashek and Harrison 2006) The leaf primodium arises on the
apex (Micol and Hake 2003) The mature angiosperm leaf consists of palisade cells
and spongy mesophyll cells sandwiched between the upper and the lower epider-
mis (Figure 14) The epidermis possesses guard cells with associated stomata that
function in gas exchange KNOX genes affect meristem maintenance and suitable
patterning of organ formation (Hake et al 2004) In dissected leaves KNOX genes
are expressed in leaf primordia (Hake et al 2004) Hake et al (2004) suggest that
An introduction to cells and their organellesWilliam V DashekRetired Faculty Adult Degree Program Mary Baldwin College Staunton VA USA
CHapter 1
2 Plant cells and their organelles
KNOX genes may be important in the diversity of leaf form Extensive discussions
of leaf development occur in Sinha (1999) Micol and Hake (2003) and Efroni
et al (2010) Under appropriate stimuli the vegetative apex can be converted to a
floral apex (Figure 15) Photoperiod (Mazumdar 2013) such as short days and
long days and combinations of the two is one such stimulus (Glover 2007
Kinmonth‐Schultz et al 2013) This induction results in the production of florigen
(Turck et al 2008) the flowering hormone (Zeevaart 2006) While early reports
suggest that florigen is an mRNA species (Huang et al 2005) a more recent inves-
tigation indicates that florigen is a protein complex (Yang et al 2007 Taoka et al
2013) Taoka et al state that florigen protein is encoded by the gene Flowering
Locus T in Arabidopsis species (Shresth et al 2014) It is believed that florigen is
induced in leaves and that it moves through the phloem to the shoot apex Plant
hormones (see Appendix A) can influence floral development (Howell 1998)
Gibberellins (Blaacutezquez et al 1998) auxins and jasmonic acid can affect petal
development In contrast auxin can influence gynoecium development The ABC
model has been proposed for regulating the development of floral parts (Soltis
et al 2006) The A gene expression is responsible for sepals while the petals are
the result of co‐expression of A and B genes The B and C genes are responsible for
stamen development and carpels require C genes In certain plants vernalization
(low temperature) can induce flowering in certain plants (Kemi et al 2013)
A diagram of the mature angiosperm plant body is presented in Figure 16 Plant
Primary phloem bres
CO
par
A
Epidermis
Cortex
Phloem
Vascularcambium
Secondaryxylem
Figure 11 Plant cell types Left parenchyma (par) and collenchyma (co) Right
sclerenchyma Source Evert (2006) Reproduced with permission of John Wiley amp Sons
Tab
le 1
1 P
lan
t ce
ll t
ypes
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Epid
erm
al c
ells
Uns
peci
aliz
ed c
ells
one
laye
r of
cel
ls in
thi
ckne
ss o
uter
cov
erin
g of
var
ious
pla
nt p
arts
varia
ble
in s
hape
but
oft
en t
abul
ar
Ever
t (2
006)
Ex
ampl
es
G
uard
cel
lsSp
ecia
lized
epi
derm
al c
ells
cre
scen
t sh
aped
con
tain
chl
orop
last
s f
orm
def
ines
sto
mat
al p
ore
Will
e an
d Lu
cas
(198
4)
Su
bsid
iary
cel
lsC
ells
whi
ch s
ubte
nd t
he s
tom
atal
gua
rd c
ells
http
an
ubis
ru
acz
aM
ain
AN
ATO
MY
gua
rdce
llsh
tml
Tr
icho
mes
An
outg
row
th o
f an
epi
derm
al c
ell
can
be u
nice
llula
r or
mul
ticel
lula
rC
allo
w (2
000)
Pare
nchy
ma
cells
Isod
iam
etric
thi
n‐w
alle
d pr
imar
y ce
ll w
all
in s
ome
inst
ance
s m
ay h
ave
seco
ndar
y w
alls
not
high
ly d
iffer
entia
ted
fun
ctio
n in
pho
tosy
nthe
sis
sec
retio
n o
rgan
ic n
utrie
nt a
nd w
ater
stor
age
reg
ener
atio
n in
wou
nd h
ealin
g
Ever
t (2
006)
and
Saj
eva
and
Mau
seth
(199
1)
Ex
ampl
es
Tr
ansf
er c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
lasm
alem
ma
grea
tly e
xpan
ded
irre
gula
r ex
tens
ions
of
cell
wal
l int
o pr
otop
lasm
tra
nsfe
r di
ssol
ved
subs
tanc
es b
etw
een
adja
cent
cel
l oc
cur
in p
ith
and
cort
ex o
f st
ems
and
root
s p
hoto
synt
hetic
tis
sues
of
leav
es f
lesh
of
succ
ulen
t fr
uits
endo
sper
m o
f se
eds
Das
hek
et a
l (1
971)
and
Off
ler
et a
l
(200
3)
Col
lenc
hym
a ce
llsLa
mel
lar
or p
late
col
lenc
hym
a w
ith t
hick
enin
gs o
n th
e ta
ngen
tial w
alls
Ang
ular
col
lenc
hym
a w
ith t
hick
enin
gs a
roun
d th
e ce
ll w
alls
Pres
ent
in a
eria
l por
tions
of
the
plan
t bo
dy
Vasc
ular
cel
lsEv
ert
(200
6)
Ph
loem
Siev
e ce
lls
Siev
e el
emen
ts
Com
pani
on c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
osse
ss n
umer
ous
plas
mod
esm
atal
con
nect
ions
Opa
rka
and
Turg
eon
(199
9)
Alb
umin
ous
cells
in
gym
nosp
erm
s
Abs
ence
of
star
ch c
ytop
lasm
ic b
ridge
s w
ith s
ieve
cel
ls d
ense
pro
topl
asm
abu
ndan
ce o
f
poly
som
es h
ighl
y co
nden
sed
euch
rom
atin
and
abu
ndan
t m
itoch
ondr
ia
Alo
si a
nd A
lfier
i (19
72) a
nd
Saut
er e
t al
(19
76)
X
ylem
Trac
heid
s
Vess
els
Long
tap
erin
g ce
ll w
ith li
gnifi
ed s
econ
dary
wal
l thi
cken
ings
can
hav
e pi
ts in
wal
ls d
evoi
d of
prot
opla
sm a
t m
atur
ity n
ot a
s sp
ecia
lized
as
vess
els
wid
espr
ead
Tyre
e an
d Zi
mm
erm
an (2
002)
Fuku
da (2
004)
and
Eve
rt (2
006)
(Con
tinue
d )
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Spec
ializ
ed c
ells
ndash H
ydat
hode
s
(mod
ified
par
ts o
f le
aves
and
leaf
tip
s or
mar
gins
)
Con
sist
of
term
inal
tra
chei
ds e
pith
em t
hin‐
wal
led
chlo
ropl
ast‐
defic
ient
cel
ls a
she
ath
with
wat
er p
ores
gut
tatio
n di
scha
rge
of li
quid
con
tain
ing
vario
us d
isso
lved
sol
utes
fro
m a
leaf
rsquos
inte
rior
Lers
ten
and
Cur
tis (1
996)
http
sw
ww
bio
sciu
texa
sed
u a
nd
Mae
da a
nd M
aeda
(198
8)
Latic
ifer
cells
Cel
ls o
r a
serie
s of
cel
ls w
hich
pro
duce
late
xFa
hn (1
990)
Pic
kard
(200
8) a
nd
Botw
ebu
wsp
Edu
Si
mpl
eSi
ngle
-cel
led
C
ompo
und
and
artic
ulat
ed
Uni
on o
f ce
lls c
ompo
und
in o
rigin
and
con
sist
of
long
itudi
nal c
hain
s of
cel
ls w
all s
epar
atin
g
cells
rem
ain
inta
ct c
an b
ecom
e pe
rfor
ated
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entir
ely
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oved
Salt
glan
dsM
odifi
ed t
richo
mes
tw
o‐ce
lled
and
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tione
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the
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ows
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llel t
o th
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ur in
Poa
ceae
Ever
t (2
006)
Tan
et
al (
2010
) O
ross
et a
l (1
985)
and
Tho
mso
n et
al
(198
8)
Cap
cel
l ndash la
rge
nucl
eus
and
expa
nded
cut
icle
Nai
doo
and
Nai
doo
(199
8)
Basa
l cel
l ndash n
umer
ous
and
larg
e ex
tens
ive
part
ition
ing
inva
gina
tions
of
plas
mal
emm
a
Nec
tarie
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und
in n
ecta
rines
pro
duce
nec
tar
usua
lly a
t th
e ba
se o
f a
flow
erFa
hn (1
990)
Nic
olso
n an
d N
epi (
2005
)
and
Paiv
a (2
009)
Idio
blas
tsC
ryst
al‐c
onta
inin
g ce
llsLe
rste
n an
d H
orne
r (2
005)
Ex
ampl
e
Ra
phid
esPr
oduc
e ne
edle
‐sha
ped
crys
tals
Muc
ilage
cel
lO
ccur
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e nu
mbe
r of
dic
ots
com
mon
in c
erta
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ucila
ge p
reve
nts
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orat
ion
of w
ater
by
bind
ing
to w
ater
a p
aren
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a ce
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hose
dic
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omes
pro
duce
muc
ilage
as
in s
eed
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s c
ell w
alls
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lulo
sic
and
unlig
nifie
d
http
w
ww
sbs
ute
xas
edu
mas
uetl
web
lab
web
chap
9sec
reto
ry9
1‐2
htm
l
Wes
tern
et
al (
2000
) and
Ars
ovsk
ia
et a
l (2
010)
Oil
cells
Spec
ializ
ed c
ells
app
ear
like
larg
e pa
renc
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lls c
an o
ccur
in v
ascu
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and
grou
nd t
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es
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tem
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l wal
l has
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ee d
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ct la
yers
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er t
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ner
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l lay
er
has
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dep
osite
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htt
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ica
com
and
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et
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2006
)
Dru
ses
Sphe
rical
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rega
tes
of p
rism
atic
cry
stal
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rste
n an
d H
orne
r (2
005)
Cel
ls in
non
‐ang
iosp
erm
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ytes
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mae
One
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y ce
llsht
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ide
com
fac
ulty
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viso
nbr
yolo
gy_l
inks
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Hyd
roid
sW
ater
‐con
duct
ing
cells
http
w
ww
Bio
logy
‐onl
ine
org
Lept
oids
ndash P
terid
ophy
tes
Org
anic
com
poun
d‐co
nduc
ting
cells
spo
roge
nous
cel
ls p
rese
nt in
spo
rang
ia o
f so
ri
Tab
le 1
1 (
Con
tin
ued
)
An introduction to cells and their organelles 5
development is discussed in Fosket (1999) Moore and Clark (1995) Greenland
(2003) Leyser and Day (2003) and Rudall (2007)
What is the composition of cellsCertain plant components exhibit polar growth for example the tip growth of
pollen tubes (Hepler et al 2001) The tubes elongate via the fusion of Golgi‐
derived vesicles with the plasmalemma and subsequent deposition of the vesi-
clesrsquo contents into the cell wall (Taylor and Hepler 1997 Parton et al 2001 and
others as reviewed in Malho (2006a 2006b)) In 2007 Dalgic and Dane (2005)
published a diagram depicting the now known tube‐tip structural elements and
physiological processes that facilitate tube elongation The diagram represents a
Figure 12 Angiosperm shoot meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
Figure 13 Angiosperm root meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
6 Plant cells and their organelles
significant advance over the early studies of pollen tubes as it assigns function to
ultrastructural components for example signalling molecules the Rho family of
GTPases and phosphatidylinositol 45 bisphosphate appear to be localized in the
apical plasma membrane Besides pollen tubes root hairs exhibit polar growth
Cell organelles ndash an introduction
Organelles are required for plant growth development and function (Sadava
1993 Gillham 1994 Herrmann 1994 Agrawal 2011) These organelles
(Figure 17) are the loci for a myriad of physiological and biochemical processes
(Tobin 1992 Daniell and Chase 2004 ndash see individual chapters)
There are many diagrams of a generalized plant cell Some of these are available
at wwwexplorebiologycom httpwwwdaviddarlinginfoimagesplant_celljpg
Table 12 Meristems and their derivatives
Meristems Derivatives
Primary
Protoderm Epidermis
From tunica (Evert 2006)
Procambium (provascular) Primary xylem and phloem
From corpus (Evert 2006) Vascular cambium
Ground Ground tissue pith and cortex
Lateral
Vascular cambium
Fusiform initials Secondary xylem
Secondary phloem
Ray initials (Evert 2006) Ray cells
Cork cambium
Phellogen Replaces the epidermis when cork cambium initiates stem girth
increase composed of lsquoboxlikersquo cork cells which are dead at
maturity protoplasm secretes suberin some cork cells that are
loosely packed give rise to lenticels which function in gas exchange
between the air and the stemrsquos interior httpwwwBiology‐online
org Evert (2006) httpwwwvebrioSceincevunlenvirut
Periderm (Evert 2006)
Phelloderm Parenchyma cells produced on the inside by the cork cambium
Meristems are discussed by Steeves and Sussex (1989)
Table 13 Plant tissues
Tissue system
Meristematic Ground Vascular Dermal
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
ix
Milee AgarwalScientist
Pharmacology and Toxicology Department
BV Patel PERD Centre
Ahmedabad Gujarat India
James E BidlackProfessor of Biology and CURE‐STEM
Scholar
Department of Biology
University of Central Oklahoma
Edmond OK USA
Amy M CloreProfessor of Biology
Division of Natural Sciences
New College of Florida
Sarasota FL USA
William V DashekRetired Faculty
Adult Degree Program
Mary Baldwin College
Staunton VA USA
D DavisGraduate Student
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
P DesaiScientist
Cellular and Molecular Biology Department
BV Patel PERD Centre
Ahmedabad Gujarat India
Robert DonaldsonProfessor
Department of Biological Sciences
George Washington University
Washington DC USA
Georgia DrakakakiAssociate Professor
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
Rajdeep Kaur GrewalSenior Research Fellow
Department of Physics
Bose Institute
Kolkata India
J Kenneth HooberProfessor Emeritus
School of Life Sciences
Center for Photosynthesis
Arizona State University
Tempe AZ USA
Dasmeet KaurResearch Assistant
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
Gurbachan S MiglaniVisiting Professor
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
Contributors
x Contributors
Harish PadhVice-Chancellor
Sardar Patel University
Vallabh Vidyanagar Anand
Gujarat India
Ray J RoseEmeritus Professor
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Soumen RoyAssociate Professor
Department of Physics
Bose Institute
Kolkata India
Saptarshi SinhaSenior Research Fellow
Department of Physics
Bose Institute
Kolkata India
Terence W‐Y TiewGraduate Student
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Yogesh VikalSenior Geneticist
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
TE WilkopSenior Project Scientist
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
xi
Plant Cells and their Organelles is an advanced textbook to enhance the plant
biology studentrsquos knowledge of the structure and function of plant cells and their
organelles The book assumes that the student has had introductory courses in
plant science and chemistry The book emphasizes the research literature in
plant cell biology concerning cell and organellar structure However the litera-
ture from plant physiology molecular genetics and biochemistry has been
utilized to augment the discussions of cell and organellar function
Preface
xii
Dashek is grateful to Drs WG Rosen WF Millington and DTA Lamport for
training enabling a career in teaching and research in plant biology Dashek
appreciates the grant support of the USArsquos NIH NSF DOE and USDA Forest
Service Dashek thanks Ms Katherine Mumford Ms Retha Howard and
Ms Abigail M Johnson for technical assistance in the preparation of the
manuscript
Miglani wishes to record his appreciation for Dr Darshan S Brar Honorary
Adjunct Professor School of Agricultural Biotechnology Punjab Agricultural
University Ludhiana India for his valuable technical suggestions Miglani
thanks Dr (Mrs) Parveen Chhuneja Director School of Agricultural
Biotechnology Punjab Agricultural University Ludhiana India for motivat-
ing me to prepare this volume and the Punjab Agricultural University for
providing facilities for this work
We thank the Wiley editorial staff members for their attention to detail
Acknowledgments
1
Plant Cells and their Organelles First Edition Edited by William V Dashek and Gurbachan S Miglani
copy 2017 John Wiley amp Sons Ltd Published 2017 by John Wiley amp Sons Ltd
Cells
Parenchyma chlorenchyma collenchyma and sclerenchyma are the four main
plant cell types (Figure 11 Evert 2006) Meristematic cells which occur in
shoot and root meristems are parenchyma cells Chlorenchyma cells contain
chloroplasts and lack the cell wall thickening layers of collenchyma and scleren-
chyma Certain epidermal cells can be specialized as stomata that are important
in gas exchange (Bergmann and Sack 2007) The diverse cell types (Zhang et al
2001 Yang and Liu 2007) are shown in Table 11 Photomicrographs of certain of
these cell types can be found in Evert (2006) Fahn (1990) Beck (2005) Rudall
(2007) Gunning (2009) MacAdam (2009) Wayne (2009) Beck (2009) Assmann
and Liu (2014) and Noguchi et al (2014)
How do cells ariseCells arise by cell divisions (see Chapter 8 for mitosis and meiosis) in shoot and
root (Figures 12 and 13) meristems (Table 12 Lyndon 1998 McManus and Veit
2001 Murray 2012) The shoot apex is characterized by a tunicandashcorpus organiza-
tion (Steeves and Sussex 1989) The tunica gives rise to the protoderm and its
derivative the epidermis In contrast the corpus provides the procambium which
yields the primary xylem and phloem In addition the ground tissue derives from
the corpus originating the pith and cortex Following divisions cells can differenti-
ate into tissues (Table 13) and organs of the mature plant body (Leyser and Day
2003 Sachs 2005 Dashek and Harrison 2006) The leaf primodium arises on the
apex (Micol and Hake 2003) The mature angiosperm leaf consists of palisade cells
and spongy mesophyll cells sandwiched between the upper and the lower epider-
mis (Figure 14) The epidermis possesses guard cells with associated stomata that
function in gas exchange KNOX genes affect meristem maintenance and suitable
patterning of organ formation (Hake et al 2004) In dissected leaves KNOX genes
are expressed in leaf primordia (Hake et al 2004) Hake et al (2004) suggest that
An introduction to cells and their organellesWilliam V DashekRetired Faculty Adult Degree Program Mary Baldwin College Staunton VA USA
CHapter 1
2 Plant cells and their organelles
KNOX genes may be important in the diversity of leaf form Extensive discussions
of leaf development occur in Sinha (1999) Micol and Hake (2003) and Efroni
et al (2010) Under appropriate stimuli the vegetative apex can be converted to a
floral apex (Figure 15) Photoperiod (Mazumdar 2013) such as short days and
long days and combinations of the two is one such stimulus (Glover 2007
Kinmonth‐Schultz et al 2013) This induction results in the production of florigen
(Turck et al 2008) the flowering hormone (Zeevaart 2006) While early reports
suggest that florigen is an mRNA species (Huang et al 2005) a more recent inves-
tigation indicates that florigen is a protein complex (Yang et al 2007 Taoka et al
2013) Taoka et al state that florigen protein is encoded by the gene Flowering
Locus T in Arabidopsis species (Shresth et al 2014) It is believed that florigen is
induced in leaves and that it moves through the phloem to the shoot apex Plant
hormones (see Appendix A) can influence floral development (Howell 1998)
Gibberellins (Blaacutezquez et al 1998) auxins and jasmonic acid can affect petal
development In contrast auxin can influence gynoecium development The ABC
model has been proposed for regulating the development of floral parts (Soltis
et al 2006) The A gene expression is responsible for sepals while the petals are
the result of co‐expression of A and B genes The B and C genes are responsible for
stamen development and carpels require C genes In certain plants vernalization
(low temperature) can induce flowering in certain plants (Kemi et al 2013)
A diagram of the mature angiosperm plant body is presented in Figure 16 Plant
Primary phloem bres
CO
par
A
Epidermis
Cortex
Phloem
Vascularcambium
Secondaryxylem
Figure 11 Plant cell types Left parenchyma (par) and collenchyma (co) Right
sclerenchyma Source Evert (2006) Reproduced with permission of John Wiley amp Sons
Tab
le 1
1 P
lan
t ce
ll t
ypes
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Epid
erm
al c
ells
Uns
peci
aliz
ed c
ells
one
laye
r of
cel
ls in
thi
ckne
ss o
uter
cov
erin
g of
var
ious
pla
nt p
arts
varia
ble
in s
hape
but
oft
en t
abul
ar
Ever
t (2
006)
Ex
ampl
es
G
uard
cel
lsSp
ecia
lized
epi
derm
al c
ells
cre
scen
t sh
aped
con
tain
chl
orop
last
s f
orm
def
ines
sto
mat
al p
ore
Will
e an
d Lu
cas
(198
4)
Su
bsid
iary
cel
lsC
ells
whi
ch s
ubte
nd t
he s
tom
atal
gua
rd c
ells
http
an
ubis
ru
acz
aM
ain
AN
ATO
MY
gua
rdce
llsh
tml
Tr
icho
mes
An
outg
row
th o
f an
epi
derm
al c
ell
can
be u
nice
llula
r or
mul
ticel
lula
rC
allo
w (2
000)
Pare
nchy
ma
cells
Isod
iam
etric
thi
n‐w
alle
d pr
imar
y ce
ll w
all
in s
ome
inst
ance
s m
ay h
ave
seco
ndar
y w
alls
not
high
ly d
iffer
entia
ted
fun
ctio
n in
pho
tosy
nthe
sis
sec
retio
n o
rgan
ic n
utrie
nt a
nd w
ater
stor
age
reg
ener
atio
n in
wou
nd h
ealin
g
Ever
t (2
006)
and
Saj
eva
and
Mau
seth
(199
1)
Ex
ampl
es
Tr
ansf
er c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
lasm
alem
ma
grea
tly e
xpan
ded
irre
gula
r ex
tens
ions
of
cell
wal
l int
o pr
otop
lasm
tra
nsfe
r di
ssol
ved
subs
tanc
es b
etw
een
adja
cent
cel
l oc
cur
in p
ith
and
cort
ex o
f st
ems
and
root
s p
hoto
synt
hetic
tis
sues
of
leav
es f
lesh
of
succ
ulen
t fr
uits
endo
sper
m o
f se
eds
Das
hek
et a
l (1
971)
and
Off
ler
et a
l
(200
3)
Col
lenc
hym
a ce
llsLa
mel
lar
or p
late
col
lenc
hym
a w
ith t
hick
enin
gs o
n th
e ta
ngen
tial w
alls
Ang
ular
col
lenc
hym
a w
ith t
hick
enin
gs a
roun
d th
e ce
ll w
alls
Pres
ent
in a
eria
l por
tions
of
the
plan
t bo
dy
Vasc
ular
cel
lsEv
ert
(200
6)
Ph
loem
Siev
e ce
lls
Siev
e el
emen
ts
Com
pani
on c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
osse
ss n
umer
ous
plas
mod
esm
atal
con
nect
ions
Opa
rka
and
Turg
eon
(199
9)
Alb
umin
ous
cells
in
gym
nosp
erm
s
Abs
ence
of
star
ch c
ytop
lasm
ic b
ridge
s w
ith s
ieve
cel
ls d
ense
pro
topl
asm
abu
ndan
ce o
f
poly
som
es h
ighl
y co
nden
sed
euch
rom
atin
and
abu
ndan
t m
itoch
ondr
ia
Alo
si a
nd A
lfier
i (19
72) a
nd
Saut
er e
t al
(19
76)
X
ylem
Trac
heid
s
Vess
els
Long
tap
erin
g ce
ll w
ith li
gnifi
ed s
econ
dary
wal
l thi
cken
ings
can
hav
e pi
ts in
wal
ls d
evoi
d of
prot
opla
sm a
t m
atur
ity n
ot a
s sp
ecia
lized
as
vess
els
wid
espr
ead
Tyre
e an
d Zi
mm
erm
an (2
002)
Fuku
da (2
004)
and
Eve
rt (2
006)
(Con
tinue
d )
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Spec
ializ
ed c
ells
ndash H
ydat
hode
s
(mod
ified
par
ts o
f le
aves
and
leaf
tip
s or
mar
gins
)
Con
sist
of
term
inal
tra
chei
ds e
pith
em t
hin‐
wal
led
chlo
ropl
ast‐
defic
ient
cel
ls a
she
ath
with
wat
er p
ores
gut
tatio
n di
scha
rge
of li
quid
con
tain
ing
vario
us d
isso
lved
sol
utes
fro
m a
leaf
rsquos
inte
rior
Lers
ten
and
Cur
tis (1
996)
http
sw
ww
bio
sciu
texa
sed
u a
nd
Mae
da a
nd M
aeda
(198
8)
Latic
ifer
cells
Cel
ls o
r a
serie
s of
cel
ls w
hich
pro
duce
late
xFa
hn (1
990)
Pic
kard
(200
8) a
nd
Botw
ebu
wsp
Edu
Si
mpl
eSi
ngle
-cel
led
C
ompo
und
and
artic
ulat
ed
Uni
on o
f ce
lls c
ompo
und
in o
rigin
and
con
sist
of
long
itudi
nal c
hain
s of
cel
ls w
all s
epar
atin
g
cells
rem
ain
inta
ct c
an b
ecom
e pe
rfor
ated
or
entir
ely
rem
oved
Salt
glan
dsM
odifi
ed t
richo
mes
tw
o‐ce
lled
and
posi
tione
d fla
t on
the
sur
face
in r
ows
para
llel t
o th
e le
af
surf
ace
occ
ur in
Poa
ceae
Ever
t (2
006)
Tan
et
al (
2010
) O
ross
et a
l (1
985)
and
Tho
mso
n et
al
(198
8)
Cap
cel
l ndash la
rge
nucl
eus
and
expa
nded
cut
icle
Nai
doo
and
Nai
doo
(199
8)
Basa
l cel
l ndash n
umer
ous
and
larg
e ex
tens
ive
part
ition
ing
inva
gina
tions
of
plas
mal
emm
a
Nec
tarie
sFo
und
in n
ecta
rines
pro
duce
nec
tar
usua
lly a
t th
e ba
se o
f a
flow
erFa
hn (1
990)
Nic
olso
n an
d N
epi (
2005
)
and
Paiv
a (2
009)
Idio
blas
tsC
ryst
al‐c
onta
inin
g ce
llsLe
rste
n an
d H
orne
r (2
005)
Ex
ampl
e
Ra
phid
esPr
oduc
e ne
edle
‐sha
ped
crys
tals
Muc
ilage
cel
lO
ccur
in a
larg
e nu
mbe
r of
dic
ots
com
mon
in c
erta
in c
acti
slim
y m
ucila
ge p
reve
nts
evap
orat
ion
of w
ater
by
bind
ing
to w
ater
a p
aren
chym
a ce
ll w
hose
dic
tyos
omes
pro
duce
muc
ilage
as
in s
eed
coat
s c
ell w
alls
are
cel
lulo
sic
and
unlig
nifie
d
http
w
ww
sbs
ute
xas
edu
mas
uetl
web
lab
web
chap
9sec
reto
ry9
1‐2
htm
l
Wes
tern
et
al (
2000
) and
Ars
ovsk
ia
et a
l (2
010)
Oil
cells
Spec
ializ
ed c
ells
app
ear
like
larg
e pa
renc
hym
a ce
lls c
an o
ccur
in v
ascu
lar
and
grou
nd t
issu
es
of s
tem
and
leaf
cel
l wal
l has
thr
ee d
istin
ct la
yers
cav
ity is
for
med
aft
er t
he in
ner
wal
l lay
er
has
been
dep
osite
d
Rode
las
et a
l (2
008)
htt
pbr
ittan
ica
com
and
Ler
sten
et
al (
2006
)
Dru
ses
Sphe
rical
agg
rega
tes
of p
rism
atic
cry
stal
sLe
rste
n an
d H
orne
r (2
005)
Cel
ls in
non
‐ang
iosp
erm
s
Br
yoph
ytes
Gem
mae
One
to
man
y ce
llsht
tp
build
ingt
hepr
ide
com
fac
ulty
pgda
viso
nbr
yolo
gy_l
inks
htm
Hyd
roid
sW
ater
‐con
duct
ing
cells
http
w
ww
Bio
logy
‐onl
ine
org
Lept
oids
ndash P
terid
ophy
tes
Org
anic
com
poun
d‐co
nduc
ting
cells
spo
roge
nous
cel
ls p
rese
nt in
spo
rang
ia o
f so
ri
Tab
le 1
1 (
Con
tin
ued
)
An introduction to cells and their organelles 5
development is discussed in Fosket (1999) Moore and Clark (1995) Greenland
(2003) Leyser and Day (2003) and Rudall (2007)
What is the composition of cellsCertain plant components exhibit polar growth for example the tip growth of
pollen tubes (Hepler et al 2001) The tubes elongate via the fusion of Golgi‐
derived vesicles with the plasmalemma and subsequent deposition of the vesi-
clesrsquo contents into the cell wall (Taylor and Hepler 1997 Parton et al 2001 and
others as reviewed in Malho (2006a 2006b)) In 2007 Dalgic and Dane (2005)
published a diagram depicting the now known tube‐tip structural elements and
physiological processes that facilitate tube elongation The diagram represents a
Figure 12 Angiosperm shoot meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
Figure 13 Angiosperm root meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
6 Plant cells and their organelles
significant advance over the early studies of pollen tubes as it assigns function to
ultrastructural components for example signalling molecules the Rho family of
GTPases and phosphatidylinositol 45 bisphosphate appear to be localized in the
apical plasma membrane Besides pollen tubes root hairs exhibit polar growth
Cell organelles ndash an introduction
Organelles are required for plant growth development and function (Sadava
1993 Gillham 1994 Herrmann 1994 Agrawal 2011) These organelles
(Figure 17) are the loci for a myriad of physiological and biochemical processes
(Tobin 1992 Daniell and Chase 2004 ndash see individual chapters)
There are many diagrams of a generalized plant cell Some of these are available
at wwwexplorebiologycom httpwwwdaviddarlinginfoimagesplant_celljpg
Table 12 Meristems and their derivatives
Meristems Derivatives
Primary
Protoderm Epidermis
From tunica (Evert 2006)
Procambium (provascular) Primary xylem and phloem
From corpus (Evert 2006) Vascular cambium
Ground Ground tissue pith and cortex
Lateral
Vascular cambium
Fusiform initials Secondary xylem
Secondary phloem
Ray initials (Evert 2006) Ray cells
Cork cambium
Phellogen Replaces the epidermis when cork cambium initiates stem girth
increase composed of lsquoboxlikersquo cork cells which are dead at
maturity protoplasm secretes suberin some cork cells that are
loosely packed give rise to lenticels which function in gas exchange
between the air and the stemrsquos interior httpwwwBiology‐online
org Evert (2006) httpwwwvebrioSceincevunlenvirut
Periderm (Evert 2006)
Phelloderm Parenchyma cells produced on the inside by the cork cambium
Meristems are discussed by Steeves and Sussex (1989)
Table 13 Plant tissues
Tissue system
Meristematic Ground Vascular Dermal
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
x Contributors
Harish PadhVice-Chancellor
Sardar Patel University
Vallabh Vidyanagar Anand
Gujarat India
Ray J RoseEmeritus Professor
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Soumen RoyAssociate Professor
Department of Physics
Bose Institute
Kolkata India
Saptarshi SinhaSenior Research Fellow
Department of Physics
Bose Institute
Kolkata India
Terence W‐Y TiewGraduate Student
Center of Excellence for Integrative
Legume Research
School of Environmental and Life Sciences
The University of Newcastle
Callaghan New South Wales Australia
Yogesh VikalSenior Geneticist
School of Agricultural Biotechnology
Punjab Agricultural University
Ludhiana India
TE WilkopSenior Project Scientist
Hellman Fellow Plant Sciences
Department of Plant Sciences
University of California Davis
Davis CA USA
xi
Plant Cells and their Organelles is an advanced textbook to enhance the plant
biology studentrsquos knowledge of the structure and function of plant cells and their
organelles The book assumes that the student has had introductory courses in
plant science and chemistry The book emphasizes the research literature in
plant cell biology concerning cell and organellar structure However the litera-
ture from plant physiology molecular genetics and biochemistry has been
utilized to augment the discussions of cell and organellar function
Preface
xii
Dashek is grateful to Drs WG Rosen WF Millington and DTA Lamport for
training enabling a career in teaching and research in plant biology Dashek
appreciates the grant support of the USArsquos NIH NSF DOE and USDA Forest
Service Dashek thanks Ms Katherine Mumford Ms Retha Howard and
Ms Abigail M Johnson for technical assistance in the preparation of the
manuscript
Miglani wishes to record his appreciation for Dr Darshan S Brar Honorary
Adjunct Professor School of Agricultural Biotechnology Punjab Agricultural
University Ludhiana India for his valuable technical suggestions Miglani
thanks Dr (Mrs) Parveen Chhuneja Director School of Agricultural
Biotechnology Punjab Agricultural University Ludhiana India for motivat-
ing me to prepare this volume and the Punjab Agricultural University for
providing facilities for this work
We thank the Wiley editorial staff members for their attention to detail
Acknowledgments
1
Plant Cells and their Organelles First Edition Edited by William V Dashek and Gurbachan S Miglani
copy 2017 John Wiley amp Sons Ltd Published 2017 by John Wiley amp Sons Ltd
Cells
Parenchyma chlorenchyma collenchyma and sclerenchyma are the four main
plant cell types (Figure 11 Evert 2006) Meristematic cells which occur in
shoot and root meristems are parenchyma cells Chlorenchyma cells contain
chloroplasts and lack the cell wall thickening layers of collenchyma and scleren-
chyma Certain epidermal cells can be specialized as stomata that are important
in gas exchange (Bergmann and Sack 2007) The diverse cell types (Zhang et al
2001 Yang and Liu 2007) are shown in Table 11 Photomicrographs of certain of
these cell types can be found in Evert (2006) Fahn (1990) Beck (2005) Rudall
(2007) Gunning (2009) MacAdam (2009) Wayne (2009) Beck (2009) Assmann
and Liu (2014) and Noguchi et al (2014)
How do cells ariseCells arise by cell divisions (see Chapter 8 for mitosis and meiosis) in shoot and
root (Figures 12 and 13) meristems (Table 12 Lyndon 1998 McManus and Veit
2001 Murray 2012) The shoot apex is characterized by a tunicandashcorpus organiza-
tion (Steeves and Sussex 1989) The tunica gives rise to the protoderm and its
derivative the epidermis In contrast the corpus provides the procambium which
yields the primary xylem and phloem In addition the ground tissue derives from
the corpus originating the pith and cortex Following divisions cells can differenti-
ate into tissues (Table 13) and organs of the mature plant body (Leyser and Day
2003 Sachs 2005 Dashek and Harrison 2006) The leaf primodium arises on the
apex (Micol and Hake 2003) The mature angiosperm leaf consists of palisade cells
and spongy mesophyll cells sandwiched between the upper and the lower epider-
mis (Figure 14) The epidermis possesses guard cells with associated stomata that
function in gas exchange KNOX genes affect meristem maintenance and suitable
patterning of organ formation (Hake et al 2004) In dissected leaves KNOX genes
are expressed in leaf primordia (Hake et al 2004) Hake et al (2004) suggest that
An introduction to cells and their organellesWilliam V DashekRetired Faculty Adult Degree Program Mary Baldwin College Staunton VA USA
CHapter 1
2 Plant cells and their organelles
KNOX genes may be important in the diversity of leaf form Extensive discussions
of leaf development occur in Sinha (1999) Micol and Hake (2003) and Efroni
et al (2010) Under appropriate stimuli the vegetative apex can be converted to a
floral apex (Figure 15) Photoperiod (Mazumdar 2013) such as short days and
long days and combinations of the two is one such stimulus (Glover 2007
Kinmonth‐Schultz et al 2013) This induction results in the production of florigen
(Turck et al 2008) the flowering hormone (Zeevaart 2006) While early reports
suggest that florigen is an mRNA species (Huang et al 2005) a more recent inves-
tigation indicates that florigen is a protein complex (Yang et al 2007 Taoka et al
2013) Taoka et al state that florigen protein is encoded by the gene Flowering
Locus T in Arabidopsis species (Shresth et al 2014) It is believed that florigen is
induced in leaves and that it moves through the phloem to the shoot apex Plant
hormones (see Appendix A) can influence floral development (Howell 1998)
Gibberellins (Blaacutezquez et al 1998) auxins and jasmonic acid can affect petal
development In contrast auxin can influence gynoecium development The ABC
model has been proposed for regulating the development of floral parts (Soltis
et al 2006) The A gene expression is responsible for sepals while the petals are
the result of co‐expression of A and B genes The B and C genes are responsible for
stamen development and carpels require C genes In certain plants vernalization
(low temperature) can induce flowering in certain plants (Kemi et al 2013)
A diagram of the mature angiosperm plant body is presented in Figure 16 Plant
Primary phloem bres
CO
par
A
Epidermis
Cortex
Phloem
Vascularcambium
Secondaryxylem
Figure 11 Plant cell types Left parenchyma (par) and collenchyma (co) Right
sclerenchyma Source Evert (2006) Reproduced with permission of John Wiley amp Sons
Tab
le 1
1 P
lan
t ce
ll t
ypes
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Epid
erm
al c
ells
Uns
peci
aliz
ed c
ells
one
laye
r of
cel
ls in
thi
ckne
ss o
uter
cov
erin
g of
var
ious
pla
nt p
arts
varia
ble
in s
hape
but
oft
en t
abul
ar
Ever
t (2
006)
Ex
ampl
es
G
uard
cel
lsSp
ecia
lized
epi
derm
al c
ells
cre
scen
t sh
aped
con
tain
chl
orop
last
s f
orm
def
ines
sto
mat
al p
ore
Will
e an
d Lu
cas
(198
4)
Su
bsid
iary
cel
lsC
ells
whi
ch s
ubte
nd t
he s
tom
atal
gua
rd c
ells
http
an
ubis
ru
acz
aM
ain
AN
ATO
MY
gua
rdce
llsh
tml
Tr
icho
mes
An
outg
row
th o
f an
epi
derm
al c
ell
can
be u
nice
llula
r or
mul
ticel
lula
rC
allo
w (2
000)
Pare
nchy
ma
cells
Isod
iam
etric
thi
n‐w
alle
d pr
imar
y ce
ll w
all
in s
ome
inst
ance
s m
ay h
ave
seco
ndar
y w
alls
not
high
ly d
iffer
entia
ted
fun
ctio
n in
pho
tosy
nthe
sis
sec
retio
n o
rgan
ic n
utrie
nt a
nd w
ater
stor
age
reg
ener
atio
n in
wou
nd h
ealin
g
Ever
t (2
006)
and
Saj
eva
and
Mau
seth
(199
1)
Ex
ampl
es
Tr
ansf
er c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
lasm
alem
ma
grea
tly e
xpan
ded
irre
gula
r ex
tens
ions
of
cell
wal
l int
o pr
otop
lasm
tra
nsfe
r di
ssol
ved
subs
tanc
es b
etw
een
adja
cent
cel
l oc
cur
in p
ith
and
cort
ex o
f st
ems
and
root
s p
hoto
synt
hetic
tis
sues
of
leav
es f
lesh
of
succ
ulen
t fr
uits
endo
sper
m o
f se
eds
Das
hek
et a
l (1
971)
and
Off
ler
et a
l
(200
3)
Col
lenc
hym
a ce
llsLa
mel
lar
or p
late
col
lenc
hym
a w
ith t
hick
enin
gs o
n th
e ta
ngen
tial w
alls
Ang
ular
col
lenc
hym
a w
ith t
hick
enin
gs a
roun
d th
e ce
ll w
alls
Pres
ent
in a
eria
l por
tions
of
the
plan
t bo
dy
Vasc
ular
cel
lsEv
ert
(200
6)
Ph
loem
Siev
e ce
lls
Siev
e el
emen
ts
Com
pani
on c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
osse
ss n
umer
ous
plas
mod
esm
atal
con
nect
ions
Opa
rka
and
Turg
eon
(199
9)
Alb
umin
ous
cells
in
gym
nosp
erm
s
Abs
ence
of
star
ch c
ytop
lasm
ic b
ridge
s w
ith s
ieve
cel
ls d
ense
pro
topl
asm
abu
ndan
ce o
f
poly
som
es h
ighl
y co
nden
sed
euch
rom
atin
and
abu
ndan
t m
itoch
ondr
ia
Alo
si a
nd A
lfier
i (19
72) a
nd
Saut
er e
t al
(19
76)
X
ylem
Trac
heid
s
Vess
els
Long
tap
erin
g ce
ll w
ith li
gnifi
ed s
econ
dary
wal
l thi
cken
ings
can
hav
e pi
ts in
wal
ls d
evoi
d of
prot
opla
sm a
t m
atur
ity n
ot a
s sp
ecia
lized
as
vess
els
wid
espr
ead
Tyre
e an
d Zi
mm
erm
an (2
002)
Fuku
da (2
004)
and
Eve
rt (2
006)
(Con
tinue
d )
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Spec
ializ
ed c
ells
ndash H
ydat
hode
s
(mod
ified
par
ts o
f le
aves
and
leaf
tip
s or
mar
gins
)
Con
sist
of
term
inal
tra
chei
ds e
pith
em t
hin‐
wal
led
chlo
ropl
ast‐
defic
ient
cel
ls a
she
ath
with
wat
er p
ores
gut
tatio
n di
scha
rge
of li
quid
con
tain
ing
vario
us d
isso
lved
sol
utes
fro
m a
leaf
rsquos
inte
rior
Lers
ten
and
Cur
tis (1
996)
http
sw
ww
bio
sciu
texa
sed
u a
nd
Mae
da a
nd M
aeda
(198
8)
Latic
ifer
cells
Cel
ls o
r a
serie
s of
cel
ls w
hich
pro
duce
late
xFa
hn (1
990)
Pic
kard
(200
8) a
nd
Botw
ebu
wsp
Edu
Si
mpl
eSi
ngle
-cel
led
C
ompo
und
and
artic
ulat
ed
Uni
on o
f ce
lls c
ompo
und
in o
rigin
and
con
sist
of
long
itudi
nal c
hain
s of
cel
ls w
all s
epar
atin
g
cells
rem
ain
inta
ct c
an b
ecom
e pe
rfor
ated
or
entir
ely
rem
oved
Salt
glan
dsM
odifi
ed t
richo
mes
tw
o‐ce
lled
and
posi
tione
d fla
t on
the
sur
face
in r
ows
para
llel t
o th
e le
af
surf
ace
occ
ur in
Poa
ceae
Ever
t (2
006)
Tan
et
al (
2010
) O
ross
et a
l (1
985)
and
Tho
mso
n et
al
(198
8)
Cap
cel
l ndash la
rge
nucl
eus
and
expa
nded
cut
icle
Nai
doo
and
Nai
doo
(199
8)
Basa
l cel
l ndash n
umer
ous
and
larg
e ex
tens
ive
part
ition
ing
inva
gina
tions
of
plas
mal
emm
a
Nec
tarie
sFo
und
in n
ecta
rines
pro
duce
nec
tar
usua
lly a
t th
e ba
se o
f a
flow
erFa
hn (1
990)
Nic
olso
n an
d N
epi (
2005
)
and
Paiv
a (2
009)
Idio
blas
tsC
ryst
al‐c
onta
inin
g ce
llsLe
rste
n an
d H
orne
r (2
005)
Ex
ampl
e
Ra
phid
esPr
oduc
e ne
edle
‐sha
ped
crys
tals
Muc
ilage
cel
lO
ccur
in a
larg
e nu
mbe
r of
dic
ots
com
mon
in c
erta
in c
acti
slim
y m
ucila
ge p
reve
nts
evap
orat
ion
of w
ater
by
bind
ing
to w
ater
a p
aren
chym
a ce
ll w
hose
dic
tyos
omes
pro
duce
muc
ilage
as
in s
eed
coat
s c
ell w
alls
are
cel
lulo
sic
and
unlig
nifie
d
http
w
ww
sbs
ute
xas
edu
mas
uetl
web
lab
web
chap
9sec
reto
ry9
1‐2
htm
l
Wes
tern
et
al (
2000
) and
Ars
ovsk
ia
et a
l (2
010)
Oil
cells
Spec
ializ
ed c
ells
app
ear
like
larg
e pa
renc
hym
a ce
lls c
an o
ccur
in v
ascu
lar
and
grou
nd t
issu
es
of s
tem
and
leaf
cel
l wal
l has
thr
ee d
istin
ct la
yers
cav
ity is
for
med
aft
er t
he in
ner
wal
l lay
er
has
been
dep
osite
d
Rode
las
et a
l (2
008)
htt
pbr
ittan
ica
com
and
Ler
sten
et
al (
2006
)
Dru
ses
Sphe
rical
agg
rega
tes
of p
rism
atic
cry
stal
sLe
rste
n an
d H
orne
r (2
005)
Cel
ls in
non
‐ang
iosp
erm
s
Br
yoph
ytes
Gem
mae
One
to
man
y ce
llsht
tp
build
ingt
hepr
ide
com
fac
ulty
pgda
viso
nbr
yolo
gy_l
inks
htm
Hyd
roid
sW
ater
‐con
duct
ing
cells
http
w
ww
Bio
logy
‐onl
ine
org
Lept
oids
ndash P
terid
ophy
tes
Org
anic
com
poun
d‐co
nduc
ting
cells
spo
roge
nous
cel
ls p
rese
nt in
spo
rang
ia o
f so
ri
Tab
le 1
1 (
Con
tin
ued
)
An introduction to cells and their organelles 5
development is discussed in Fosket (1999) Moore and Clark (1995) Greenland
(2003) Leyser and Day (2003) and Rudall (2007)
What is the composition of cellsCertain plant components exhibit polar growth for example the tip growth of
pollen tubes (Hepler et al 2001) The tubes elongate via the fusion of Golgi‐
derived vesicles with the plasmalemma and subsequent deposition of the vesi-
clesrsquo contents into the cell wall (Taylor and Hepler 1997 Parton et al 2001 and
others as reviewed in Malho (2006a 2006b)) In 2007 Dalgic and Dane (2005)
published a diagram depicting the now known tube‐tip structural elements and
physiological processes that facilitate tube elongation The diagram represents a
Figure 12 Angiosperm shoot meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
Figure 13 Angiosperm root meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
6 Plant cells and their organelles
significant advance over the early studies of pollen tubes as it assigns function to
ultrastructural components for example signalling molecules the Rho family of
GTPases and phosphatidylinositol 45 bisphosphate appear to be localized in the
apical plasma membrane Besides pollen tubes root hairs exhibit polar growth
Cell organelles ndash an introduction
Organelles are required for plant growth development and function (Sadava
1993 Gillham 1994 Herrmann 1994 Agrawal 2011) These organelles
(Figure 17) are the loci for a myriad of physiological and biochemical processes
(Tobin 1992 Daniell and Chase 2004 ndash see individual chapters)
There are many diagrams of a generalized plant cell Some of these are available
at wwwexplorebiologycom httpwwwdaviddarlinginfoimagesplant_celljpg
Table 12 Meristems and their derivatives
Meristems Derivatives
Primary
Protoderm Epidermis
From tunica (Evert 2006)
Procambium (provascular) Primary xylem and phloem
From corpus (Evert 2006) Vascular cambium
Ground Ground tissue pith and cortex
Lateral
Vascular cambium
Fusiform initials Secondary xylem
Secondary phloem
Ray initials (Evert 2006) Ray cells
Cork cambium
Phellogen Replaces the epidermis when cork cambium initiates stem girth
increase composed of lsquoboxlikersquo cork cells which are dead at
maturity protoplasm secretes suberin some cork cells that are
loosely packed give rise to lenticels which function in gas exchange
between the air and the stemrsquos interior httpwwwBiology‐online
org Evert (2006) httpwwwvebrioSceincevunlenvirut
Periderm (Evert 2006)
Phelloderm Parenchyma cells produced on the inside by the cork cambium
Meristems are discussed by Steeves and Sussex (1989)
Table 13 Plant tissues
Tissue system
Meristematic Ground Vascular Dermal
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
xi
Plant Cells and their Organelles is an advanced textbook to enhance the plant
biology studentrsquos knowledge of the structure and function of plant cells and their
organelles The book assumes that the student has had introductory courses in
plant science and chemistry The book emphasizes the research literature in
plant cell biology concerning cell and organellar structure However the litera-
ture from plant physiology molecular genetics and biochemistry has been
utilized to augment the discussions of cell and organellar function
Preface
xii
Dashek is grateful to Drs WG Rosen WF Millington and DTA Lamport for
training enabling a career in teaching and research in plant biology Dashek
appreciates the grant support of the USArsquos NIH NSF DOE and USDA Forest
Service Dashek thanks Ms Katherine Mumford Ms Retha Howard and
Ms Abigail M Johnson for technical assistance in the preparation of the
manuscript
Miglani wishes to record his appreciation for Dr Darshan S Brar Honorary
Adjunct Professor School of Agricultural Biotechnology Punjab Agricultural
University Ludhiana India for his valuable technical suggestions Miglani
thanks Dr (Mrs) Parveen Chhuneja Director School of Agricultural
Biotechnology Punjab Agricultural University Ludhiana India for motivat-
ing me to prepare this volume and the Punjab Agricultural University for
providing facilities for this work
We thank the Wiley editorial staff members for their attention to detail
Acknowledgments
1
Plant Cells and their Organelles First Edition Edited by William V Dashek and Gurbachan S Miglani
copy 2017 John Wiley amp Sons Ltd Published 2017 by John Wiley amp Sons Ltd
Cells
Parenchyma chlorenchyma collenchyma and sclerenchyma are the four main
plant cell types (Figure 11 Evert 2006) Meristematic cells which occur in
shoot and root meristems are parenchyma cells Chlorenchyma cells contain
chloroplasts and lack the cell wall thickening layers of collenchyma and scleren-
chyma Certain epidermal cells can be specialized as stomata that are important
in gas exchange (Bergmann and Sack 2007) The diverse cell types (Zhang et al
2001 Yang and Liu 2007) are shown in Table 11 Photomicrographs of certain of
these cell types can be found in Evert (2006) Fahn (1990) Beck (2005) Rudall
(2007) Gunning (2009) MacAdam (2009) Wayne (2009) Beck (2009) Assmann
and Liu (2014) and Noguchi et al (2014)
How do cells ariseCells arise by cell divisions (see Chapter 8 for mitosis and meiosis) in shoot and
root (Figures 12 and 13) meristems (Table 12 Lyndon 1998 McManus and Veit
2001 Murray 2012) The shoot apex is characterized by a tunicandashcorpus organiza-
tion (Steeves and Sussex 1989) The tunica gives rise to the protoderm and its
derivative the epidermis In contrast the corpus provides the procambium which
yields the primary xylem and phloem In addition the ground tissue derives from
the corpus originating the pith and cortex Following divisions cells can differenti-
ate into tissues (Table 13) and organs of the mature plant body (Leyser and Day
2003 Sachs 2005 Dashek and Harrison 2006) The leaf primodium arises on the
apex (Micol and Hake 2003) The mature angiosperm leaf consists of palisade cells
and spongy mesophyll cells sandwiched between the upper and the lower epider-
mis (Figure 14) The epidermis possesses guard cells with associated stomata that
function in gas exchange KNOX genes affect meristem maintenance and suitable
patterning of organ formation (Hake et al 2004) In dissected leaves KNOX genes
are expressed in leaf primordia (Hake et al 2004) Hake et al (2004) suggest that
An introduction to cells and their organellesWilliam V DashekRetired Faculty Adult Degree Program Mary Baldwin College Staunton VA USA
CHapter 1
2 Plant cells and their organelles
KNOX genes may be important in the diversity of leaf form Extensive discussions
of leaf development occur in Sinha (1999) Micol and Hake (2003) and Efroni
et al (2010) Under appropriate stimuli the vegetative apex can be converted to a
floral apex (Figure 15) Photoperiod (Mazumdar 2013) such as short days and
long days and combinations of the two is one such stimulus (Glover 2007
Kinmonth‐Schultz et al 2013) This induction results in the production of florigen
(Turck et al 2008) the flowering hormone (Zeevaart 2006) While early reports
suggest that florigen is an mRNA species (Huang et al 2005) a more recent inves-
tigation indicates that florigen is a protein complex (Yang et al 2007 Taoka et al
2013) Taoka et al state that florigen protein is encoded by the gene Flowering
Locus T in Arabidopsis species (Shresth et al 2014) It is believed that florigen is
induced in leaves and that it moves through the phloem to the shoot apex Plant
hormones (see Appendix A) can influence floral development (Howell 1998)
Gibberellins (Blaacutezquez et al 1998) auxins and jasmonic acid can affect petal
development In contrast auxin can influence gynoecium development The ABC
model has been proposed for regulating the development of floral parts (Soltis
et al 2006) The A gene expression is responsible for sepals while the petals are
the result of co‐expression of A and B genes The B and C genes are responsible for
stamen development and carpels require C genes In certain plants vernalization
(low temperature) can induce flowering in certain plants (Kemi et al 2013)
A diagram of the mature angiosperm plant body is presented in Figure 16 Plant
Primary phloem bres
CO
par
A
Epidermis
Cortex
Phloem
Vascularcambium
Secondaryxylem
Figure 11 Plant cell types Left parenchyma (par) and collenchyma (co) Right
sclerenchyma Source Evert (2006) Reproduced with permission of John Wiley amp Sons
Tab
le 1
1 P
lan
t ce
ll t
ypes
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Epid
erm
al c
ells
Uns
peci
aliz
ed c
ells
one
laye
r of
cel
ls in
thi
ckne
ss o
uter
cov
erin
g of
var
ious
pla
nt p
arts
varia
ble
in s
hape
but
oft
en t
abul
ar
Ever
t (2
006)
Ex
ampl
es
G
uard
cel
lsSp
ecia
lized
epi
derm
al c
ells
cre
scen
t sh
aped
con
tain
chl
orop
last
s f
orm
def
ines
sto
mat
al p
ore
Will
e an
d Lu
cas
(198
4)
Su
bsid
iary
cel
lsC
ells
whi
ch s
ubte
nd t
he s
tom
atal
gua
rd c
ells
http
an
ubis
ru
acz
aM
ain
AN
ATO
MY
gua
rdce
llsh
tml
Tr
icho
mes
An
outg
row
th o
f an
epi
derm
al c
ell
can
be u
nice
llula
r or
mul
ticel
lula
rC
allo
w (2
000)
Pare
nchy
ma
cells
Isod
iam
etric
thi
n‐w
alle
d pr
imar
y ce
ll w
all
in s
ome
inst
ance
s m
ay h
ave
seco
ndar
y w
alls
not
high
ly d
iffer
entia
ted
fun
ctio
n in
pho
tosy
nthe
sis
sec
retio
n o
rgan
ic n
utrie
nt a
nd w
ater
stor
age
reg
ener
atio
n in
wou
nd h
ealin
g
Ever
t (2
006)
and
Saj
eva
and
Mau
seth
(199
1)
Ex
ampl
es
Tr
ansf
er c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
lasm
alem
ma
grea
tly e
xpan
ded
irre
gula
r ex
tens
ions
of
cell
wal
l int
o pr
otop
lasm
tra
nsfe
r di
ssol
ved
subs
tanc
es b
etw
een
adja
cent
cel
l oc
cur
in p
ith
and
cort
ex o
f st
ems
and
root
s p
hoto
synt
hetic
tis
sues
of
leav
es f
lesh
of
succ
ulen
t fr
uits
endo
sper
m o
f se
eds
Das
hek
et a
l (1
971)
and
Off
ler
et a
l
(200
3)
Col
lenc
hym
a ce
llsLa
mel
lar
or p
late
col
lenc
hym
a w
ith t
hick
enin
gs o
n th
e ta
ngen
tial w
alls
Ang
ular
col
lenc
hym
a w
ith t
hick
enin
gs a
roun
d th
e ce
ll w
alls
Pres
ent
in a
eria
l por
tions
of
the
plan
t bo
dy
Vasc
ular
cel
lsEv
ert
(200
6)
Ph
loem
Siev
e ce
lls
Siev
e el
emen
ts
Com
pani
on c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
osse
ss n
umer
ous
plas
mod
esm
atal
con
nect
ions
Opa
rka
and
Turg
eon
(199
9)
Alb
umin
ous
cells
in
gym
nosp
erm
s
Abs
ence
of
star
ch c
ytop
lasm
ic b
ridge
s w
ith s
ieve
cel
ls d
ense
pro
topl
asm
abu
ndan
ce o
f
poly
som
es h
ighl
y co
nden
sed
euch
rom
atin
and
abu
ndan
t m
itoch
ondr
ia
Alo
si a
nd A
lfier
i (19
72) a
nd
Saut
er e
t al
(19
76)
X
ylem
Trac
heid
s
Vess
els
Long
tap
erin
g ce
ll w
ith li
gnifi
ed s
econ
dary
wal
l thi
cken
ings
can
hav
e pi
ts in
wal
ls d
evoi
d of
prot
opla
sm a
t m
atur
ity n
ot a
s sp
ecia
lized
as
vess
els
wid
espr
ead
Tyre
e an
d Zi
mm
erm
an (2
002)
Fuku
da (2
004)
and
Eve
rt (2
006)
(Con
tinue
d )
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Spec
ializ
ed c
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ified
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ts o
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aves
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tip
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gins
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sist
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rsquos
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ten
and
Cur
tis (1
996)
http
sw
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bio
sciu
texa
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da a
nd M
aeda
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8)
Latic
ifer
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Cel
ls o
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hich
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itudi
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t (2
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ross
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mso
n et
al
(198
8)
Cap
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l ndash la
rge
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and
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Basa
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Tab
le 1
1 (
Con
tin
ued
)
An introduction to cells and their organelles 5
development is discussed in Fosket (1999) Moore and Clark (1995) Greenland
(2003) Leyser and Day (2003) and Rudall (2007)
What is the composition of cellsCertain plant components exhibit polar growth for example the tip growth of
pollen tubes (Hepler et al 2001) The tubes elongate via the fusion of Golgi‐
derived vesicles with the plasmalemma and subsequent deposition of the vesi-
clesrsquo contents into the cell wall (Taylor and Hepler 1997 Parton et al 2001 and
others as reviewed in Malho (2006a 2006b)) In 2007 Dalgic and Dane (2005)
published a diagram depicting the now known tube‐tip structural elements and
physiological processes that facilitate tube elongation The diagram represents a
Figure 12 Angiosperm shoot meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
Figure 13 Angiosperm root meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
6 Plant cells and their organelles
significant advance over the early studies of pollen tubes as it assigns function to
ultrastructural components for example signalling molecules the Rho family of
GTPases and phosphatidylinositol 45 bisphosphate appear to be localized in the
apical plasma membrane Besides pollen tubes root hairs exhibit polar growth
Cell organelles ndash an introduction
Organelles are required for plant growth development and function (Sadava
1993 Gillham 1994 Herrmann 1994 Agrawal 2011) These organelles
(Figure 17) are the loci for a myriad of physiological and biochemical processes
(Tobin 1992 Daniell and Chase 2004 ndash see individual chapters)
There are many diagrams of a generalized plant cell Some of these are available
at wwwexplorebiologycom httpwwwdaviddarlinginfoimagesplant_celljpg
Table 12 Meristems and their derivatives
Meristems Derivatives
Primary
Protoderm Epidermis
From tunica (Evert 2006)
Procambium (provascular) Primary xylem and phloem
From corpus (Evert 2006) Vascular cambium
Ground Ground tissue pith and cortex
Lateral
Vascular cambium
Fusiform initials Secondary xylem
Secondary phloem
Ray initials (Evert 2006) Ray cells
Cork cambium
Phellogen Replaces the epidermis when cork cambium initiates stem girth
increase composed of lsquoboxlikersquo cork cells which are dead at
maturity protoplasm secretes suberin some cork cells that are
loosely packed give rise to lenticels which function in gas exchange
between the air and the stemrsquos interior httpwwwBiology‐online
org Evert (2006) httpwwwvebrioSceincevunlenvirut
Periderm (Evert 2006)
Phelloderm Parenchyma cells produced on the inside by the cork cambium
Meristems are discussed by Steeves and Sussex (1989)
Table 13 Plant tissues
Tissue system
Meristematic Ground Vascular Dermal
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
xii
Dashek is grateful to Drs WG Rosen WF Millington and DTA Lamport for
training enabling a career in teaching and research in plant biology Dashek
appreciates the grant support of the USArsquos NIH NSF DOE and USDA Forest
Service Dashek thanks Ms Katherine Mumford Ms Retha Howard and
Ms Abigail M Johnson for technical assistance in the preparation of the
manuscript
Miglani wishes to record his appreciation for Dr Darshan S Brar Honorary
Adjunct Professor School of Agricultural Biotechnology Punjab Agricultural
University Ludhiana India for his valuable technical suggestions Miglani
thanks Dr (Mrs) Parveen Chhuneja Director School of Agricultural
Biotechnology Punjab Agricultural University Ludhiana India for motivat-
ing me to prepare this volume and the Punjab Agricultural University for
providing facilities for this work
We thank the Wiley editorial staff members for their attention to detail
Acknowledgments
1
Plant Cells and their Organelles First Edition Edited by William V Dashek and Gurbachan S Miglani
copy 2017 John Wiley amp Sons Ltd Published 2017 by John Wiley amp Sons Ltd
Cells
Parenchyma chlorenchyma collenchyma and sclerenchyma are the four main
plant cell types (Figure 11 Evert 2006) Meristematic cells which occur in
shoot and root meristems are parenchyma cells Chlorenchyma cells contain
chloroplasts and lack the cell wall thickening layers of collenchyma and scleren-
chyma Certain epidermal cells can be specialized as stomata that are important
in gas exchange (Bergmann and Sack 2007) The diverse cell types (Zhang et al
2001 Yang and Liu 2007) are shown in Table 11 Photomicrographs of certain of
these cell types can be found in Evert (2006) Fahn (1990) Beck (2005) Rudall
(2007) Gunning (2009) MacAdam (2009) Wayne (2009) Beck (2009) Assmann
and Liu (2014) and Noguchi et al (2014)
How do cells ariseCells arise by cell divisions (see Chapter 8 for mitosis and meiosis) in shoot and
root (Figures 12 and 13) meristems (Table 12 Lyndon 1998 McManus and Veit
2001 Murray 2012) The shoot apex is characterized by a tunicandashcorpus organiza-
tion (Steeves and Sussex 1989) The tunica gives rise to the protoderm and its
derivative the epidermis In contrast the corpus provides the procambium which
yields the primary xylem and phloem In addition the ground tissue derives from
the corpus originating the pith and cortex Following divisions cells can differenti-
ate into tissues (Table 13) and organs of the mature plant body (Leyser and Day
2003 Sachs 2005 Dashek and Harrison 2006) The leaf primodium arises on the
apex (Micol and Hake 2003) The mature angiosperm leaf consists of palisade cells
and spongy mesophyll cells sandwiched between the upper and the lower epider-
mis (Figure 14) The epidermis possesses guard cells with associated stomata that
function in gas exchange KNOX genes affect meristem maintenance and suitable
patterning of organ formation (Hake et al 2004) In dissected leaves KNOX genes
are expressed in leaf primordia (Hake et al 2004) Hake et al (2004) suggest that
An introduction to cells and their organellesWilliam V DashekRetired Faculty Adult Degree Program Mary Baldwin College Staunton VA USA
CHapter 1
2 Plant cells and their organelles
KNOX genes may be important in the diversity of leaf form Extensive discussions
of leaf development occur in Sinha (1999) Micol and Hake (2003) and Efroni
et al (2010) Under appropriate stimuli the vegetative apex can be converted to a
floral apex (Figure 15) Photoperiod (Mazumdar 2013) such as short days and
long days and combinations of the two is one such stimulus (Glover 2007
Kinmonth‐Schultz et al 2013) This induction results in the production of florigen
(Turck et al 2008) the flowering hormone (Zeevaart 2006) While early reports
suggest that florigen is an mRNA species (Huang et al 2005) a more recent inves-
tigation indicates that florigen is a protein complex (Yang et al 2007 Taoka et al
2013) Taoka et al state that florigen protein is encoded by the gene Flowering
Locus T in Arabidopsis species (Shresth et al 2014) It is believed that florigen is
induced in leaves and that it moves through the phloem to the shoot apex Plant
hormones (see Appendix A) can influence floral development (Howell 1998)
Gibberellins (Blaacutezquez et al 1998) auxins and jasmonic acid can affect petal
development In contrast auxin can influence gynoecium development The ABC
model has been proposed for regulating the development of floral parts (Soltis
et al 2006) The A gene expression is responsible for sepals while the petals are
the result of co‐expression of A and B genes The B and C genes are responsible for
stamen development and carpels require C genes In certain plants vernalization
(low temperature) can induce flowering in certain plants (Kemi et al 2013)
A diagram of the mature angiosperm plant body is presented in Figure 16 Plant
Primary phloem bres
CO
par
A
Epidermis
Cortex
Phloem
Vascularcambium
Secondaryxylem
Figure 11 Plant cell types Left parenchyma (par) and collenchyma (co) Right
sclerenchyma Source Evert (2006) Reproduced with permission of John Wiley amp Sons
Tab
le 1
1 P
lan
t ce
ll t
ypes
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Epid
erm
al c
ells
Uns
peci
aliz
ed c
ells
one
laye
r of
cel
ls in
thi
ckne
ss o
uter
cov
erin
g of
var
ious
pla
nt p
arts
varia
ble
in s
hape
but
oft
en t
abul
ar
Ever
t (2
006)
Ex
ampl
es
G
uard
cel
lsSp
ecia
lized
epi
derm
al c
ells
cre
scen
t sh
aped
con
tain
chl
orop
last
s f
orm
def
ines
sto
mat
al p
ore
Will
e an
d Lu
cas
(198
4)
Su
bsid
iary
cel
lsC
ells
whi
ch s
ubte
nd t
he s
tom
atal
gua
rd c
ells
http
an
ubis
ru
acz
aM
ain
AN
ATO
MY
gua
rdce
llsh
tml
Tr
icho
mes
An
outg
row
th o
f an
epi
derm
al c
ell
can
be u
nice
llula
r or
mul
ticel
lula
rC
allo
w (2
000)
Pare
nchy
ma
cells
Isod
iam
etric
thi
n‐w
alle
d pr
imar
y ce
ll w
all
in s
ome
inst
ance
s m
ay h
ave
seco
ndar
y w
alls
not
high
ly d
iffer
entia
ted
fun
ctio
n in
pho
tosy
nthe
sis
sec
retio
n o
rgan
ic n
utrie
nt a
nd w
ater
stor
age
reg
ener
atio
n in
wou
nd h
ealin
g
Ever
t (2
006)
and
Saj
eva
and
Mau
seth
(199
1)
Ex
ampl
es
Tr
ansf
er c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
lasm
alem
ma
grea
tly e
xpan
ded
irre
gula
r ex
tens
ions
of
cell
wal
l int
o pr
otop
lasm
tra
nsfe
r di
ssol
ved
subs
tanc
es b
etw
een
adja
cent
cel
l oc
cur
in p
ith
and
cort
ex o
f st
ems
and
root
s p
hoto
synt
hetic
tis
sues
of
leav
es f
lesh
of
succ
ulen
t fr
uits
endo
sper
m o
f se
eds
Das
hek
et a
l (1
971)
and
Off
ler
et a
l
(200
3)
Col
lenc
hym
a ce
llsLa
mel
lar
or p
late
col
lenc
hym
a w
ith t
hick
enin
gs o
n th
e ta
ngen
tial w
alls
Ang
ular
col
lenc
hym
a w
ith t
hick
enin
gs a
roun
d th
e ce
ll w
alls
Pres
ent
in a
eria
l por
tions
of
the
plan
t bo
dy
Vasc
ular
cel
lsEv
ert
(200
6)
Ph
loem
Siev
e ce
lls
Siev
e el
emen
ts
Com
pani
on c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
osse
ss n
umer
ous
plas
mod
esm
atal
con
nect
ions
Opa
rka
and
Turg
eon
(199
9)
Alb
umin
ous
cells
in
gym
nosp
erm
s
Abs
ence
of
star
ch c
ytop
lasm
ic b
ridge
s w
ith s
ieve
cel
ls d
ense
pro
topl
asm
abu
ndan
ce o
f
poly
som
es h
ighl
y co
nden
sed
euch
rom
atin
and
abu
ndan
t m
itoch
ondr
ia
Alo
si a
nd A
lfier
i (19
72) a
nd
Saut
er e
t al
(19
76)
X
ylem
Trac
heid
s
Vess
els
Long
tap
erin
g ce
ll w
ith li
gnifi
ed s
econ
dary
wal
l thi
cken
ings
can
hav
e pi
ts in
wal
ls d
evoi
d of
prot
opla
sm a
t m
atur
ity n
ot a
s sp
ecia
lized
as
vess
els
wid
espr
ead
Tyre
e an
d Zi
mm
erm
an (2
002)
Fuku
da (2
004)
and
Eve
rt (2
006)
(Con
tinue
d )
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Spec
ializ
ed c
ells
ndash H
ydat
hode
s
(mod
ified
par
ts o
f le
aves
and
leaf
tip
s or
mar
gins
)
Con
sist
of
term
inal
tra
chei
ds e
pith
em t
hin‐
wal
led
chlo
ropl
ast‐
defic
ient
cel
ls a
she
ath
with
wat
er p
ores
gut
tatio
n di
scha
rge
of li
quid
con
tain
ing
vario
us d
isso
lved
sol
utes
fro
m a
leaf
rsquos
inte
rior
Lers
ten
and
Cur
tis (1
996)
http
sw
ww
bio
sciu
texa
sed
u a
nd
Mae
da a
nd M
aeda
(198
8)
Latic
ifer
cells
Cel
ls o
r a
serie
s of
cel
ls w
hich
pro
duce
late
xFa
hn (1
990)
Pic
kard
(200
8) a
nd
Botw
ebu
wsp
Edu
Si
mpl
eSi
ngle
-cel
led
C
ompo
und
and
artic
ulat
ed
Uni
on o
f ce
lls c
ompo
und
in o
rigin
and
con
sist
of
long
itudi
nal c
hain
s of
cel
ls w
all s
epar
atin
g
cells
rem
ain
inta
ct c
an b
ecom
e pe
rfor
ated
or
entir
ely
rem
oved
Salt
glan
dsM
odifi
ed t
richo
mes
tw
o‐ce
lled
and
posi
tione
d fla
t on
the
sur
face
in r
ows
para
llel t
o th
e le
af
surf
ace
occ
ur in
Poa
ceae
Ever
t (2
006)
Tan
et
al (
2010
) O
ross
et a
l (1
985)
and
Tho
mso
n et
al
(198
8)
Cap
cel
l ndash la
rge
nucl
eus
and
expa
nded
cut
icle
Nai
doo
and
Nai
doo
(199
8)
Basa
l cel
l ndash n
umer
ous
and
larg
e ex
tens
ive
part
ition
ing
inva
gina
tions
of
plas
mal
emm
a
Nec
tarie
sFo
und
in n
ecta
rines
pro
duce
nec
tar
usua
lly a
t th
e ba
se o
f a
flow
erFa
hn (1
990)
Nic
olso
n an
d N
epi (
2005
)
and
Paiv
a (2
009)
Idio
blas
tsC
ryst
al‐c
onta
inin
g ce
llsLe
rste
n an
d H
orne
r (2
005)
Ex
ampl
e
Ra
phid
esPr
oduc
e ne
edle
‐sha
ped
crys
tals
Muc
ilage
cel
lO
ccur
in a
larg
e nu
mbe
r of
dic
ots
com
mon
in c
erta
in c
acti
slim
y m
ucila
ge p
reve
nts
evap
orat
ion
of w
ater
by
bind
ing
to w
ater
a p
aren
chym
a ce
ll w
hose
dic
tyos
omes
pro
duce
muc
ilage
as
in s
eed
coat
s c
ell w
alls
are
cel
lulo
sic
and
unlig
nifie
d
http
w
ww
sbs
ute
xas
edu
mas
uetl
web
lab
web
chap
9sec
reto
ry9
1‐2
htm
l
Wes
tern
et
al (
2000
) and
Ars
ovsk
ia
et a
l (2
010)
Oil
cells
Spec
ializ
ed c
ells
app
ear
like
larg
e pa
renc
hym
a ce
lls c
an o
ccur
in v
ascu
lar
and
grou
nd t
issu
es
of s
tem
and
leaf
cel
l wal
l has
thr
ee d
istin
ct la
yers
cav
ity is
for
med
aft
er t
he in
ner
wal
l lay
er
has
been
dep
osite
d
Rode
las
et a
l (2
008)
htt
pbr
ittan
ica
com
and
Ler
sten
et
al (
2006
)
Dru
ses
Sphe
rical
agg
rega
tes
of p
rism
atic
cry
stal
sLe
rste
n an
d H
orne
r (2
005)
Cel
ls in
non
‐ang
iosp
erm
s
Br
yoph
ytes
Gem
mae
One
to
man
y ce
llsht
tp
build
ingt
hepr
ide
com
fac
ulty
pgda
viso
nbr
yolo
gy_l
inks
htm
Hyd
roid
sW
ater
‐con
duct
ing
cells
http
w
ww
Bio
logy
‐onl
ine
org
Lept
oids
ndash P
terid
ophy
tes
Org
anic
com
poun
d‐co
nduc
ting
cells
spo
roge
nous
cel
ls p
rese
nt in
spo
rang
ia o
f so
ri
Tab
le 1
1 (
Con
tin
ued
)
An introduction to cells and their organelles 5
development is discussed in Fosket (1999) Moore and Clark (1995) Greenland
(2003) Leyser and Day (2003) and Rudall (2007)
What is the composition of cellsCertain plant components exhibit polar growth for example the tip growth of
pollen tubes (Hepler et al 2001) The tubes elongate via the fusion of Golgi‐
derived vesicles with the plasmalemma and subsequent deposition of the vesi-
clesrsquo contents into the cell wall (Taylor and Hepler 1997 Parton et al 2001 and
others as reviewed in Malho (2006a 2006b)) In 2007 Dalgic and Dane (2005)
published a diagram depicting the now known tube‐tip structural elements and
physiological processes that facilitate tube elongation The diagram represents a
Figure 12 Angiosperm shoot meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
Figure 13 Angiosperm root meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
6 Plant cells and their organelles
significant advance over the early studies of pollen tubes as it assigns function to
ultrastructural components for example signalling molecules the Rho family of
GTPases and phosphatidylinositol 45 bisphosphate appear to be localized in the
apical plasma membrane Besides pollen tubes root hairs exhibit polar growth
Cell organelles ndash an introduction
Organelles are required for plant growth development and function (Sadava
1993 Gillham 1994 Herrmann 1994 Agrawal 2011) These organelles
(Figure 17) are the loci for a myriad of physiological and biochemical processes
(Tobin 1992 Daniell and Chase 2004 ndash see individual chapters)
There are many diagrams of a generalized plant cell Some of these are available
at wwwexplorebiologycom httpwwwdaviddarlinginfoimagesplant_celljpg
Table 12 Meristems and their derivatives
Meristems Derivatives
Primary
Protoderm Epidermis
From tunica (Evert 2006)
Procambium (provascular) Primary xylem and phloem
From corpus (Evert 2006) Vascular cambium
Ground Ground tissue pith and cortex
Lateral
Vascular cambium
Fusiform initials Secondary xylem
Secondary phloem
Ray initials (Evert 2006) Ray cells
Cork cambium
Phellogen Replaces the epidermis when cork cambium initiates stem girth
increase composed of lsquoboxlikersquo cork cells which are dead at
maturity protoplasm secretes suberin some cork cells that are
loosely packed give rise to lenticels which function in gas exchange
between the air and the stemrsquos interior httpwwwBiology‐online
org Evert (2006) httpwwwvebrioSceincevunlenvirut
Periderm (Evert 2006)
Phelloderm Parenchyma cells produced on the inside by the cork cambium
Meristems are discussed by Steeves and Sussex (1989)
Table 13 Plant tissues
Tissue system
Meristematic Ground Vascular Dermal
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
1
Plant Cells and their Organelles First Edition Edited by William V Dashek and Gurbachan S Miglani
copy 2017 John Wiley amp Sons Ltd Published 2017 by John Wiley amp Sons Ltd
Cells
Parenchyma chlorenchyma collenchyma and sclerenchyma are the four main
plant cell types (Figure 11 Evert 2006) Meristematic cells which occur in
shoot and root meristems are parenchyma cells Chlorenchyma cells contain
chloroplasts and lack the cell wall thickening layers of collenchyma and scleren-
chyma Certain epidermal cells can be specialized as stomata that are important
in gas exchange (Bergmann and Sack 2007) The diverse cell types (Zhang et al
2001 Yang and Liu 2007) are shown in Table 11 Photomicrographs of certain of
these cell types can be found in Evert (2006) Fahn (1990) Beck (2005) Rudall
(2007) Gunning (2009) MacAdam (2009) Wayne (2009) Beck (2009) Assmann
and Liu (2014) and Noguchi et al (2014)
How do cells ariseCells arise by cell divisions (see Chapter 8 for mitosis and meiosis) in shoot and
root (Figures 12 and 13) meristems (Table 12 Lyndon 1998 McManus and Veit
2001 Murray 2012) The shoot apex is characterized by a tunicandashcorpus organiza-
tion (Steeves and Sussex 1989) The tunica gives rise to the protoderm and its
derivative the epidermis In contrast the corpus provides the procambium which
yields the primary xylem and phloem In addition the ground tissue derives from
the corpus originating the pith and cortex Following divisions cells can differenti-
ate into tissues (Table 13) and organs of the mature plant body (Leyser and Day
2003 Sachs 2005 Dashek and Harrison 2006) The leaf primodium arises on the
apex (Micol and Hake 2003) The mature angiosperm leaf consists of palisade cells
and spongy mesophyll cells sandwiched between the upper and the lower epider-
mis (Figure 14) The epidermis possesses guard cells with associated stomata that
function in gas exchange KNOX genes affect meristem maintenance and suitable
patterning of organ formation (Hake et al 2004) In dissected leaves KNOX genes
are expressed in leaf primordia (Hake et al 2004) Hake et al (2004) suggest that
An introduction to cells and their organellesWilliam V DashekRetired Faculty Adult Degree Program Mary Baldwin College Staunton VA USA
CHapter 1
2 Plant cells and their organelles
KNOX genes may be important in the diversity of leaf form Extensive discussions
of leaf development occur in Sinha (1999) Micol and Hake (2003) and Efroni
et al (2010) Under appropriate stimuli the vegetative apex can be converted to a
floral apex (Figure 15) Photoperiod (Mazumdar 2013) such as short days and
long days and combinations of the two is one such stimulus (Glover 2007
Kinmonth‐Schultz et al 2013) This induction results in the production of florigen
(Turck et al 2008) the flowering hormone (Zeevaart 2006) While early reports
suggest that florigen is an mRNA species (Huang et al 2005) a more recent inves-
tigation indicates that florigen is a protein complex (Yang et al 2007 Taoka et al
2013) Taoka et al state that florigen protein is encoded by the gene Flowering
Locus T in Arabidopsis species (Shresth et al 2014) It is believed that florigen is
induced in leaves and that it moves through the phloem to the shoot apex Plant
hormones (see Appendix A) can influence floral development (Howell 1998)
Gibberellins (Blaacutezquez et al 1998) auxins and jasmonic acid can affect petal
development In contrast auxin can influence gynoecium development The ABC
model has been proposed for regulating the development of floral parts (Soltis
et al 2006) The A gene expression is responsible for sepals while the petals are
the result of co‐expression of A and B genes The B and C genes are responsible for
stamen development and carpels require C genes In certain plants vernalization
(low temperature) can induce flowering in certain plants (Kemi et al 2013)
A diagram of the mature angiosperm plant body is presented in Figure 16 Plant
Primary phloem bres
CO
par
A
Epidermis
Cortex
Phloem
Vascularcambium
Secondaryxylem
Figure 11 Plant cell types Left parenchyma (par) and collenchyma (co) Right
sclerenchyma Source Evert (2006) Reproduced with permission of John Wiley amp Sons
Tab
le 1
1 P
lan
t ce
ll t
ypes
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Epid
erm
al c
ells
Uns
peci
aliz
ed c
ells
one
laye
r of
cel
ls in
thi
ckne
ss o
uter
cov
erin
g of
var
ious
pla
nt p
arts
varia
ble
in s
hape
but
oft
en t
abul
ar
Ever
t (2
006)
Ex
ampl
es
G
uard
cel
lsSp
ecia
lized
epi
derm
al c
ells
cre
scen
t sh
aped
con
tain
chl
orop
last
s f
orm
def
ines
sto
mat
al p
ore
Will
e an
d Lu
cas
(198
4)
Su
bsid
iary
cel
lsC
ells
whi
ch s
ubte
nd t
he s
tom
atal
gua
rd c
ells
http
an
ubis
ru
acz
aM
ain
AN
ATO
MY
gua
rdce
llsh
tml
Tr
icho
mes
An
outg
row
th o
f an
epi
derm
al c
ell
can
be u
nice
llula
r or
mul
ticel
lula
rC
allo
w (2
000)
Pare
nchy
ma
cells
Isod
iam
etric
thi
n‐w
alle
d pr
imar
y ce
ll w
all
in s
ome
inst
ance
s m
ay h
ave
seco
ndar
y w
alls
not
high
ly d
iffer
entia
ted
fun
ctio
n in
pho
tosy
nthe
sis
sec
retio
n o
rgan
ic n
utrie
nt a
nd w
ater
stor
age
reg
ener
atio
n in
wou
nd h
ealin
g
Ever
t (2
006)
and
Saj
eva
and
Mau
seth
(199
1)
Ex
ampl
es
Tr
ansf
er c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
lasm
alem
ma
grea
tly e
xpan
ded
irre
gula
r ex
tens
ions
of
cell
wal
l int
o pr
otop
lasm
tra
nsfe
r di
ssol
ved
subs
tanc
es b
etw
een
adja
cent
cel
l oc
cur
in p
ith
and
cort
ex o
f st
ems
and
root
s p
hoto
synt
hetic
tis
sues
of
leav
es f
lesh
of
succ
ulen
t fr
uits
endo
sper
m o
f se
eds
Das
hek
et a
l (1
971)
and
Off
ler
et a
l
(200
3)
Col
lenc
hym
a ce
llsLa
mel
lar
or p
late
col
lenc
hym
a w
ith t
hick
enin
gs o
n th
e ta
ngen
tial w
alls
Ang
ular
col
lenc
hym
a w
ith t
hick
enin
gs a
roun
d th
e ce
ll w
alls
Pres
ent
in a
eria
l por
tions
of
the
plan
t bo
dy
Vasc
ular
cel
lsEv
ert
(200
6)
Ph
loem
Siev
e ce
lls
Siev
e el
emen
ts
Com
pani
on c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
osse
ss n
umer
ous
plas
mod
esm
atal
con
nect
ions
Opa
rka
and
Turg
eon
(199
9)
Alb
umin
ous
cells
in
gym
nosp
erm
s
Abs
ence
of
star
ch c
ytop
lasm
ic b
ridge
s w
ith s
ieve
cel
ls d
ense
pro
topl
asm
abu
ndan
ce o
f
poly
som
es h
ighl
y co
nden
sed
euch
rom
atin
and
abu
ndan
t m
itoch
ondr
ia
Alo
si a
nd A
lfier
i (19
72) a
nd
Saut
er e
t al
(19
76)
X
ylem
Trac
heid
s
Vess
els
Long
tap
erin
g ce
ll w
ith li
gnifi
ed s
econ
dary
wal
l thi
cken
ings
can
hav
e pi
ts in
wal
ls d
evoi
d of
prot
opla
sm a
t m
atur
ity n
ot a
s sp
ecia
lized
as
vess
els
wid
espr
ead
Tyre
e an
d Zi
mm
erm
an (2
002)
Fuku
da (2
004)
and
Eve
rt (2
006)
(Con
tinue
d )
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Spec
ializ
ed c
ells
ndash H
ydat
hode
s
(mod
ified
par
ts o
f le
aves
and
leaf
tip
s or
mar
gins
)
Con
sist
of
term
inal
tra
chei
ds e
pith
em t
hin‐
wal
led
chlo
ropl
ast‐
defic
ient
cel
ls a
she
ath
with
wat
er p
ores
gut
tatio
n di
scha
rge
of li
quid
con
tain
ing
vario
us d
isso
lved
sol
utes
fro
m a
leaf
rsquos
inte
rior
Lers
ten
and
Cur
tis (1
996)
http
sw
ww
bio
sciu
texa
sed
u a
nd
Mae
da a
nd M
aeda
(198
8)
Latic
ifer
cells
Cel
ls o
r a
serie
s of
cel
ls w
hich
pro
duce
late
xFa
hn (1
990)
Pic
kard
(200
8) a
nd
Botw
ebu
wsp
Edu
Si
mpl
eSi
ngle
-cel
led
C
ompo
und
and
artic
ulat
ed
Uni
on o
f ce
lls c
ompo
und
in o
rigin
and
con
sist
of
long
itudi
nal c
hain
s of
cel
ls w
all s
epar
atin
g
cells
rem
ain
inta
ct c
an b
ecom
e pe
rfor
ated
or
entir
ely
rem
oved
Salt
glan
dsM
odifi
ed t
richo
mes
tw
o‐ce
lled
and
posi
tione
d fla
t on
the
sur
face
in r
ows
para
llel t
o th
e le
af
surf
ace
occ
ur in
Poa
ceae
Ever
t (2
006)
Tan
et
al (
2010
) O
ross
et a
l (1
985)
and
Tho
mso
n et
al
(198
8)
Cap
cel
l ndash la
rge
nucl
eus
and
expa
nded
cut
icle
Nai
doo
and
Nai
doo
(199
8)
Basa
l cel
l ndash n
umer
ous
and
larg
e ex
tens
ive
part
ition
ing
inva
gina
tions
of
plas
mal
emm
a
Nec
tarie
sFo
und
in n
ecta
rines
pro
duce
nec
tar
usua
lly a
t th
e ba
se o
f a
flow
erFa
hn (1
990)
Nic
olso
n an
d N
epi (
2005
)
and
Paiv
a (2
009)
Idio
blas
tsC
ryst
al‐c
onta
inin
g ce
llsLe
rste
n an
d H
orne
r (2
005)
Ex
ampl
e
Ra
phid
esPr
oduc
e ne
edle
‐sha
ped
crys
tals
Muc
ilage
cel
lO
ccur
in a
larg
e nu
mbe
r of
dic
ots
com
mon
in c
erta
in c
acti
slim
y m
ucila
ge p
reve
nts
evap
orat
ion
of w
ater
by
bind
ing
to w
ater
a p
aren
chym
a ce
ll w
hose
dic
tyos
omes
pro
duce
muc
ilage
as
in s
eed
coat
s c
ell w
alls
are
cel
lulo
sic
and
unlig
nifie
d
http
w
ww
sbs
ute
xas
edu
mas
uetl
web
lab
web
chap
9sec
reto
ry9
1‐2
htm
l
Wes
tern
et
al (
2000
) and
Ars
ovsk
ia
et a
l (2
010)
Oil
cells
Spec
ializ
ed c
ells
app
ear
like
larg
e pa
renc
hym
a ce
lls c
an o
ccur
in v
ascu
lar
and
grou
nd t
issu
es
of s
tem
and
leaf
cel
l wal
l has
thr
ee d
istin
ct la
yers
cav
ity is
for
med
aft
er t
he in
ner
wal
l lay
er
has
been
dep
osite
d
Rode
las
et a
l (2
008)
htt
pbr
ittan
ica
com
and
Ler
sten
et
al (
2006
)
Dru
ses
Sphe
rical
agg
rega
tes
of p
rism
atic
cry
stal
sLe
rste
n an
d H
orne
r (2
005)
Cel
ls in
non
‐ang
iosp
erm
s
Br
yoph
ytes
Gem
mae
One
to
man
y ce
llsht
tp
build
ingt
hepr
ide
com
fac
ulty
pgda
viso
nbr
yolo
gy_l
inks
htm
Hyd
roid
sW
ater
‐con
duct
ing
cells
http
w
ww
Bio
logy
‐onl
ine
org
Lept
oids
ndash P
terid
ophy
tes
Org
anic
com
poun
d‐co
nduc
ting
cells
spo
roge
nous
cel
ls p
rese
nt in
spo
rang
ia o
f so
ri
Tab
le 1
1 (
Con
tin
ued
)
An introduction to cells and their organelles 5
development is discussed in Fosket (1999) Moore and Clark (1995) Greenland
(2003) Leyser and Day (2003) and Rudall (2007)
What is the composition of cellsCertain plant components exhibit polar growth for example the tip growth of
pollen tubes (Hepler et al 2001) The tubes elongate via the fusion of Golgi‐
derived vesicles with the plasmalemma and subsequent deposition of the vesi-
clesrsquo contents into the cell wall (Taylor and Hepler 1997 Parton et al 2001 and
others as reviewed in Malho (2006a 2006b)) In 2007 Dalgic and Dane (2005)
published a diagram depicting the now known tube‐tip structural elements and
physiological processes that facilitate tube elongation The diagram represents a
Figure 12 Angiosperm shoot meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
Figure 13 Angiosperm root meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
6 Plant cells and their organelles
significant advance over the early studies of pollen tubes as it assigns function to
ultrastructural components for example signalling molecules the Rho family of
GTPases and phosphatidylinositol 45 bisphosphate appear to be localized in the
apical plasma membrane Besides pollen tubes root hairs exhibit polar growth
Cell organelles ndash an introduction
Organelles are required for plant growth development and function (Sadava
1993 Gillham 1994 Herrmann 1994 Agrawal 2011) These organelles
(Figure 17) are the loci for a myriad of physiological and biochemical processes
(Tobin 1992 Daniell and Chase 2004 ndash see individual chapters)
There are many diagrams of a generalized plant cell Some of these are available
at wwwexplorebiologycom httpwwwdaviddarlinginfoimagesplant_celljpg
Table 12 Meristems and their derivatives
Meristems Derivatives
Primary
Protoderm Epidermis
From tunica (Evert 2006)
Procambium (provascular) Primary xylem and phloem
From corpus (Evert 2006) Vascular cambium
Ground Ground tissue pith and cortex
Lateral
Vascular cambium
Fusiform initials Secondary xylem
Secondary phloem
Ray initials (Evert 2006) Ray cells
Cork cambium
Phellogen Replaces the epidermis when cork cambium initiates stem girth
increase composed of lsquoboxlikersquo cork cells which are dead at
maturity protoplasm secretes suberin some cork cells that are
loosely packed give rise to lenticels which function in gas exchange
between the air and the stemrsquos interior httpwwwBiology‐online
org Evert (2006) httpwwwvebrioSceincevunlenvirut
Periderm (Evert 2006)
Phelloderm Parenchyma cells produced on the inside by the cork cambium
Meristems are discussed by Steeves and Sussex (1989)
Table 13 Plant tissues
Tissue system
Meristematic Ground Vascular Dermal
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
2 Plant cells and their organelles
KNOX genes may be important in the diversity of leaf form Extensive discussions
of leaf development occur in Sinha (1999) Micol and Hake (2003) and Efroni
et al (2010) Under appropriate stimuli the vegetative apex can be converted to a
floral apex (Figure 15) Photoperiod (Mazumdar 2013) such as short days and
long days and combinations of the two is one such stimulus (Glover 2007
Kinmonth‐Schultz et al 2013) This induction results in the production of florigen
(Turck et al 2008) the flowering hormone (Zeevaart 2006) While early reports
suggest that florigen is an mRNA species (Huang et al 2005) a more recent inves-
tigation indicates that florigen is a protein complex (Yang et al 2007 Taoka et al
2013) Taoka et al state that florigen protein is encoded by the gene Flowering
Locus T in Arabidopsis species (Shresth et al 2014) It is believed that florigen is
induced in leaves and that it moves through the phloem to the shoot apex Plant
hormones (see Appendix A) can influence floral development (Howell 1998)
Gibberellins (Blaacutezquez et al 1998) auxins and jasmonic acid can affect petal
development In contrast auxin can influence gynoecium development The ABC
model has been proposed for regulating the development of floral parts (Soltis
et al 2006) The A gene expression is responsible for sepals while the petals are
the result of co‐expression of A and B genes The B and C genes are responsible for
stamen development and carpels require C genes In certain plants vernalization
(low temperature) can induce flowering in certain plants (Kemi et al 2013)
A diagram of the mature angiosperm plant body is presented in Figure 16 Plant
Primary phloem bres
CO
par
A
Epidermis
Cortex
Phloem
Vascularcambium
Secondaryxylem
Figure 11 Plant cell types Left parenchyma (par) and collenchyma (co) Right
sclerenchyma Source Evert (2006) Reproduced with permission of John Wiley amp Sons
Tab
le 1
1 P
lan
t ce
ll t
ypes
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Epid
erm
al c
ells
Uns
peci
aliz
ed c
ells
one
laye
r of
cel
ls in
thi
ckne
ss o
uter
cov
erin
g of
var
ious
pla
nt p
arts
varia
ble
in s
hape
but
oft
en t
abul
ar
Ever
t (2
006)
Ex
ampl
es
G
uard
cel
lsSp
ecia
lized
epi
derm
al c
ells
cre
scen
t sh
aped
con
tain
chl
orop
last
s f
orm
def
ines
sto
mat
al p
ore
Will
e an
d Lu
cas
(198
4)
Su
bsid
iary
cel
lsC
ells
whi
ch s
ubte
nd t
he s
tom
atal
gua
rd c
ells
http
an
ubis
ru
acz
aM
ain
AN
ATO
MY
gua
rdce
llsh
tml
Tr
icho
mes
An
outg
row
th o
f an
epi
derm
al c
ell
can
be u
nice
llula
r or
mul
ticel
lula
rC
allo
w (2
000)
Pare
nchy
ma
cells
Isod
iam
etric
thi
n‐w
alle
d pr
imar
y ce
ll w
all
in s
ome
inst
ance
s m
ay h
ave
seco
ndar
y w
alls
not
high
ly d
iffer
entia
ted
fun
ctio
n in
pho
tosy
nthe
sis
sec
retio
n o
rgan
ic n
utrie
nt a
nd w
ater
stor
age
reg
ener
atio
n in
wou
nd h
ealin
g
Ever
t (2
006)
and
Saj
eva
and
Mau
seth
(199
1)
Ex
ampl
es
Tr
ansf
er c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
lasm
alem
ma
grea
tly e
xpan
ded
irre
gula
r ex
tens
ions
of
cell
wal
l int
o pr
otop
lasm
tra
nsfe
r di
ssol
ved
subs
tanc
es b
etw
een
adja
cent
cel
l oc
cur
in p
ith
and
cort
ex o
f st
ems
and
root
s p
hoto
synt
hetic
tis
sues
of
leav
es f
lesh
of
succ
ulen
t fr
uits
endo
sper
m o
f se
eds
Das
hek
et a
l (1
971)
and
Off
ler
et a
l
(200
3)
Col
lenc
hym
a ce
llsLa
mel
lar
or p
late
col
lenc
hym
a w
ith t
hick
enin
gs o
n th
e ta
ngen
tial w
alls
Ang
ular
col
lenc
hym
a w
ith t
hick
enin
gs a
roun
d th
e ce
ll w
alls
Pres
ent
in a
eria
l por
tions
of
the
plan
t bo
dy
Vasc
ular
cel
lsEv
ert
(200
6)
Ph
loem
Siev
e ce
lls
Siev
e el
emen
ts
Com
pani
on c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
osse
ss n
umer
ous
plas
mod
esm
atal
con
nect
ions
Opa
rka
and
Turg
eon
(199
9)
Alb
umin
ous
cells
in
gym
nosp
erm
s
Abs
ence
of
star
ch c
ytop
lasm
ic b
ridge
s w
ith s
ieve
cel
ls d
ense
pro
topl
asm
abu
ndan
ce o
f
poly
som
es h
ighl
y co
nden
sed
euch
rom
atin
and
abu
ndan
t m
itoch
ondr
ia
Alo
si a
nd A
lfier
i (19
72) a
nd
Saut
er e
t al
(19
76)
X
ylem
Trac
heid
s
Vess
els
Long
tap
erin
g ce
ll w
ith li
gnifi
ed s
econ
dary
wal
l thi
cken
ings
can
hav
e pi
ts in
wal
ls d
evoi
d of
prot
opla
sm a
t m
atur
ity n
ot a
s sp
ecia
lized
as
vess
els
wid
espr
ead
Tyre
e an
d Zi
mm
erm
an (2
002)
Fuku
da (2
004)
and
Eve
rt (2
006)
(Con
tinue
d )
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Spec
ializ
ed c
ells
ndash H
ydat
hode
s
(mod
ified
par
ts o
f le
aves
and
leaf
tip
s or
mar
gins
)
Con
sist
of
term
inal
tra
chei
ds e
pith
em t
hin‐
wal
led
chlo
ropl
ast‐
defic
ient
cel
ls a
she
ath
with
wat
er p
ores
gut
tatio
n di
scha
rge
of li
quid
con
tain
ing
vario
us d
isso
lved
sol
utes
fro
m a
leaf
rsquos
inte
rior
Lers
ten
and
Cur
tis (1
996)
http
sw
ww
bio
sciu
texa
sed
u a
nd
Mae
da a
nd M
aeda
(198
8)
Latic
ifer
cells
Cel
ls o
r a
serie
s of
cel
ls w
hich
pro
duce
late
xFa
hn (1
990)
Pic
kard
(200
8) a
nd
Botw
ebu
wsp
Edu
Si
mpl
eSi
ngle
-cel
led
C
ompo
und
and
artic
ulat
ed
Uni
on o
f ce
lls c
ompo
und
in o
rigin
and
con
sist
of
long
itudi
nal c
hain
s of
cel
ls w
all s
epar
atin
g
cells
rem
ain
inta
ct c
an b
ecom
e pe
rfor
ated
or
entir
ely
rem
oved
Salt
glan
dsM
odifi
ed t
richo
mes
tw
o‐ce
lled
and
posi
tione
d fla
t on
the
sur
face
in r
ows
para
llel t
o th
e le
af
surf
ace
occ
ur in
Poa
ceae
Ever
t (2
006)
Tan
et
al (
2010
) O
ross
et a
l (1
985)
and
Tho
mso
n et
al
(198
8)
Cap
cel
l ndash la
rge
nucl
eus
and
expa
nded
cut
icle
Nai
doo
and
Nai
doo
(199
8)
Basa
l cel
l ndash n
umer
ous
and
larg
e ex
tens
ive
part
ition
ing
inva
gina
tions
of
plas
mal
emm
a
Nec
tarie
sFo
und
in n
ecta
rines
pro
duce
nec
tar
usua
lly a
t th
e ba
se o
f a
flow
erFa
hn (1
990)
Nic
olso
n an
d N
epi (
2005
)
and
Paiv
a (2
009)
Idio
blas
tsC
ryst
al‐c
onta
inin
g ce
llsLe
rste
n an
d H
orne
r (2
005)
Ex
ampl
e
Ra
phid
esPr
oduc
e ne
edle
‐sha
ped
crys
tals
Muc
ilage
cel
lO
ccur
in a
larg
e nu
mbe
r of
dic
ots
com
mon
in c
erta
in c
acti
slim
y m
ucila
ge p
reve
nts
evap
orat
ion
of w
ater
by
bind
ing
to w
ater
a p
aren
chym
a ce
ll w
hose
dic
tyos
omes
pro
duce
muc
ilage
as
in s
eed
coat
s c
ell w
alls
are
cel
lulo
sic
and
unlig
nifie
d
http
w
ww
sbs
ute
xas
edu
mas
uetl
web
lab
web
chap
9sec
reto
ry9
1‐2
htm
l
Wes
tern
et
al (
2000
) and
Ars
ovsk
ia
et a
l (2
010)
Oil
cells
Spec
ializ
ed c
ells
app
ear
like
larg
e pa
renc
hym
a ce
lls c
an o
ccur
in v
ascu
lar
and
grou
nd t
issu
es
of s
tem
and
leaf
cel
l wal
l has
thr
ee d
istin
ct la
yers
cav
ity is
for
med
aft
er t
he in
ner
wal
l lay
er
has
been
dep
osite
d
Rode
las
et a
l (2
008)
htt
pbr
ittan
ica
com
and
Ler
sten
et
al (
2006
)
Dru
ses
Sphe
rical
agg
rega
tes
of p
rism
atic
cry
stal
sLe
rste
n an
d H
orne
r (2
005)
Cel
ls in
non
‐ang
iosp
erm
s
Br
yoph
ytes
Gem
mae
One
to
man
y ce
llsht
tp
build
ingt
hepr
ide
com
fac
ulty
pgda
viso
nbr
yolo
gy_l
inks
htm
Hyd
roid
sW
ater
‐con
duct
ing
cells
http
w
ww
Bio
logy
‐onl
ine
org
Lept
oids
ndash P
terid
ophy
tes
Org
anic
com
poun
d‐co
nduc
ting
cells
spo
roge
nous
cel
ls p
rese
nt in
spo
rang
ia o
f so
ri
Tab
le 1
1 (
Con
tin
ued
)
An introduction to cells and their organelles 5
development is discussed in Fosket (1999) Moore and Clark (1995) Greenland
(2003) Leyser and Day (2003) and Rudall (2007)
What is the composition of cellsCertain plant components exhibit polar growth for example the tip growth of
pollen tubes (Hepler et al 2001) The tubes elongate via the fusion of Golgi‐
derived vesicles with the plasmalemma and subsequent deposition of the vesi-
clesrsquo contents into the cell wall (Taylor and Hepler 1997 Parton et al 2001 and
others as reviewed in Malho (2006a 2006b)) In 2007 Dalgic and Dane (2005)
published a diagram depicting the now known tube‐tip structural elements and
physiological processes that facilitate tube elongation The diagram represents a
Figure 12 Angiosperm shoot meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
Figure 13 Angiosperm root meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
6 Plant cells and their organelles
significant advance over the early studies of pollen tubes as it assigns function to
ultrastructural components for example signalling molecules the Rho family of
GTPases and phosphatidylinositol 45 bisphosphate appear to be localized in the
apical plasma membrane Besides pollen tubes root hairs exhibit polar growth
Cell organelles ndash an introduction
Organelles are required for plant growth development and function (Sadava
1993 Gillham 1994 Herrmann 1994 Agrawal 2011) These organelles
(Figure 17) are the loci for a myriad of physiological and biochemical processes
(Tobin 1992 Daniell and Chase 2004 ndash see individual chapters)
There are many diagrams of a generalized plant cell Some of these are available
at wwwexplorebiologycom httpwwwdaviddarlinginfoimagesplant_celljpg
Table 12 Meristems and their derivatives
Meristems Derivatives
Primary
Protoderm Epidermis
From tunica (Evert 2006)
Procambium (provascular) Primary xylem and phloem
From corpus (Evert 2006) Vascular cambium
Ground Ground tissue pith and cortex
Lateral
Vascular cambium
Fusiform initials Secondary xylem
Secondary phloem
Ray initials (Evert 2006) Ray cells
Cork cambium
Phellogen Replaces the epidermis when cork cambium initiates stem girth
increase composed of lsquoboxlikersquo cork cells which are dead at
maturity protoplasm secretes suberin some cork cells that are
loosely packed give rise to lenticels which function in gas exchange
between the air and the stemrsquos interior httpwwwBiology‐online
org Evert (2006) httpwwwvebrioSceincevunlenvirut
Periderm (Evert 2006)
Phelloderm Parenchyma cells produced on the inside by the cork cambium
Meristems are discussed by Steeves and Sussex (1989)
Table 13 Plant tissues
Tissue system
Meristematic Ground Vascular Dermal
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
Tab
le 1
1 P
lan
t ce
ll t
ypes
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Epid
erm
al c
ells
Uns
peci
aliz
ed c
ells
one
laye
r of
cel
ls in
thi
ckne
ss o
uter
cov
erin
g of
var
ious
pla
nt p
arts
varia
ble
in s
hape
but
oft
en t
abul
ar
Ever
t (2
006)
Ex
ampl
es
G
uard
cel
lsSp
ecia
lized
epi
derm
al c
ells
cre
scen
t sh
aped
con
tain
chl
orop
last
s f
orm
def
ines
sto
mat
al p
ore
Will
e an
d Lu
cas
(198
4)
Su
bsid
iary
cel
lsC
ells
whi
ch s
ubte
nd t
he s
tom
atal
gua
rd c
ells
http
an
ubis
ru
acz
aM
ain
AN
ATO
MY
gua
rdce
llsh
tml
Tr
icho
mes
An
outg
row
th o
f an
epi
derm
al c
ell
can
be u
nice
llula
r or
mul
ticel
lula
rC
allo
w (2
000)
Pare
nchy
ma
cells
Isod
iam
etric
thi
n‐w
alle
d pr
imar
y ce
ll w
all
in s
ome
inst
ance
s m
ay h
ave
seco
ndar
y w
alls
not
high
ly d
iffer
entia
ted
fun
ctio
n in
pho
tosy
nthe
sis
sec
retio
n o
rgan
ic n
utrie
nt a
nd w
ater
stor
age
reg
ener
atio
n in
wou
nd h
ealin
g
Ever
t (2
006)
and
Saj
eva
and
Mau
seth
(199
1)
Ex
ampl
es
Tr
ansf
er c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
lasm
alem
ma
grea
tly e
xpan
ded
irre
gula
r ex
tens
ions
of
cell
wal
l int
o pr
otop
lasm
tra
nsfe
r di
ssol
ved
subs
tanc
es b
etw
een
adja
cent
cel
l oc
cur
in p
ith
and
cort
ex o
f st
ems
and
root
s p
hoto
synt
hetic
tis
sues
of
leav
es f
lesh
of
succ
ulen
t fr
uits
endo
sper
m o
f se
eds
Das
hek
et a
l (1
971)
and
Off
ler
et a
l
(200
3)
Col
lenc
hym
a ce
llsLa
mel
lar
or p
late
col
lenc
hym
a w
ith t
hick
enin
gs o
n th
e ta
ngen
tial w
alls
Ang
ular
col
lenc
hym
a w
ith t
hick
enin
gs a
roun
d th
e ce
ll w
alls
Pres
ent
in a
eria
l por
tions
of
the
plan
t bo
dy
Vasc
ular
cel
lsEv
ert
(200
6)
Ph
loem
Siev
e ce
lls
Siev
e el
emen
ts
Com
pani
on c
ells
Spec
ializ
ed p
aren
chym
a ce
lls p
osse
ss n
umer
ous
plas
mod
esm
atal
con
nect
ions
Opa
rka
and
Turg
eon
(199
9)
Alb
umin
ous
cells
in
gym
nosp
erm
s
Abs
ence
of
star
ch c
ytop
lasm
ic b
ridge
s w
ith s
ieve
cel
ls d
ense
pro
topl
asm
abu
ndan
ce o
f
poly
som
es h
ighl
y co
nden
sed
euch
rom
atin
and
abu
ndan
t m
itoch
ondr
ia
Alo
si a
nd A
lfier
i (19
72) a
nd
Saut
er e
t al
(19
76)
X
ylem
Trac
heid
s
Vess
els
Long
tap
erin
g ce
ll w
ith li
gnifi
ed s
econ
dary
wal
l thi
cken
ings
can
hav
e pi
ts in
wal
ls d
evoi
d of
prot
opla
sm a
t m
atur
ity n
ot a
s sp
ecia
lized
as
vess
els
wid
espr
ead
Tyre
e an
d Zi
mm
erm
an (2
002)
Fuku
da (2
004)
and
Eve
rt (2
006)
(Con
tinue
d )
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Spec
ializ
ed c
ells
ndash H
ydat
hode
s
(mod
ified
par
ts o
f le
aves
and
leaf
tip
s or
mar
gins
)
Con
sist
of
term
inal
tra
chei
ds e
pith
em t
hin‐
wal
led
chlo
ropl
ast‐
defic
ient
cel
ls a
she
ath
with
wat
er p
ores
gut
tatio
n di
scha
rge
of li
quid
con
tain
ing
vario
us d
isso
lved
sol
utes
fro
m a
leaf
rsquos
inte
rior
Lers
ten
and
Cur
tis (1
996)
http
sw
ww
bio
sciu
texa
sed
u a
nd
Mae
da a
nd M
aeda
(198
8)
Latic
ifer
cells
Cel
ls o
r a
serie
s of
cel
ls w
hich
pro
duce
late
xFa
hn (1
990)
Pic
kard
(200
8) a
nd
Botw
ebu
wsp
Edu
Si
mpl
eSi
ngle
-cel
led
C
ompo
und
and
artic
ulat
ed
Uni
on o
f ce
lls c
ompo
und
in o
rigin
and
con
sist
of
long
itudi
nal c
hain
s of
cel
ls w
all s
epar
atin
g
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ain
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ct c
an b
ecom
e pe
rfor
ated
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ely
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oved
Salt
glan
dsM
odifi
ed t
richo
mes
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o‐ce
lled
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face
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ows
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llel t
o th
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ur in
Poa
ceae
Ever
t (2
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Tan
et
al (
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) O
ross
et a
l (1
985)
and
Tho
mso
n et
al
(198
8)
Cap
cel
l ndash la
rge
nucl
eus
and
expa
nded
cut
icle
Nai
doo
and
Nai
doo
(199
8)
Basa
l cel
l ndash n
umer
ous
and
larg
e ex
tens
ive
part
ition
ing
inva
gina
tions
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plas
mal
emm
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rines
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duce
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tar
usua
lly a
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e ba
se o
f a
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erFa
hn (1
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Nic
olso
n an
d N
epi (
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)
and
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a (2
009)
Idio
blas
tsC
ryst
al‐c
onta
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g ce
llsLe
rste
n an
d H
orne
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005)
Ex
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phid
esPr
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e ne
edle
‐sha
ped
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tals
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ots
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ater
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mas
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9sec
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ry9
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l
Wes
tern
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Oil
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Spec
ializ
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ells
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e pa
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an o
ccur
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nd t
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ee d
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htt
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)
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ses
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rical
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atic
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rste
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orne
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ater
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Tab
le 1
1 (
Con
tin
ued
)
An introduction to cells and their organelles 5
development is discussed in Fosket (1999) Moore and Clark (1995) Greenland
(2003) Leyser and Day (2003) and Rudall (2007)
What is the composition of cellsCertain plant components exhibit polar growth for example the tip growth of
pollen tubes (Hepler et al 2001) The tubes elongate via the fusion of Golgi‐
derived vesicles with the plasmalemma and subsequent deposition of the vesi-
clesrsquo contents into the cell wall (Taylor and Hepler 1997 Parton et al 2001 and
others as reviewed in Malho (2006a 2006b)) In 2007 Dalgic and Dane (2005)
published a diagram depicting the now known tube‐tip structural elements and
physiological processes that facilitate tube elongation The diagram represents a
Figure 12 Angiosperm shoot meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
Figure 13 Angiosperm root meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
6 Plant cells and their organelles
significant advance over the early studies of pollen tubes as it assigns function to
ultrastructural components for example signalling molecules the Rho family of
GTPases and phosphatidylinositol 45 bisphosphate appear to be localized in the
apical plasma membrane Besides pollen tubes root hairs exhibit polar growth
Cell organelles ndash an introduction
Organelles are required for plant growth development and function (Sadava
1993 Gillham 1994 Herrmann 1994 Agrawal 2011) These organelles
(Figure 17) are the loci for a myriad of physiological and biochemical processes
(Tobin 1992 Daniell and Chase 2004 ndash see individual chapters)
There are many diagrams of a generalized plant cell Some of these are available
at wwwexplorebiologycom httpwwwdaviddarlinginfoimagesplant_celljpg
Table 12 Meristems and their derivatives
Meristems Derivatives
Primary
Protoderm Epidermis
From tunica (Evert 2006)
Procambium (provascular) Primary xylem and phloem
From corpus (Evert 2006) Vascular cambium
Ground Ground tissue pith and cortex
Lateral
Vascular cambium
Fusiform initials Secondary xylem
Secondary phloem
Ray initials (Evert 2006) Ray cells
Cork cambium
Phellogen Replaces the epidermis when cork cambium initiates stem girth
increase composed of lsquoboxlikersquo cork cells which are dead at
maturity protoplasm secretes suberin some cork cells that are
loosely packed give rise to lenticels which function in gas exchange
between the air and the stemrsquos interior httpwwwBiology‐online
org Evert (2006) httpwwwvebrioSceincevunlenvirut
Periderm (Evert 2006)
Phelloderm Parenchyma cells produced on the inside by the cork cambium
Meristems are discussed by Steeves and Sussex (1989)
Table 13 Plant tissues
Tissue system
Meristematic Ground Vascular Dermal
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
Cel
l typ
esC
har
acte
rist
ics
Ref
eren
ces
Spec
ializ
ed c
ells
ndash H
ydat
hode
s
(mod
ified
par
ts o
f le
aves
and
leaf
tip
s or
mar
gins
)
Con
sist
of
term
inal
tra
chei
ds e
pith
em t
hin‐
wal
led
chlo
ropl
ast‐
defic
ient
cel
ls a
she
ath
with
wat
er p
ores
gut
tatio
n di
scha
rge
of li
quid
con
tain
ing
vario
us d
isso
lved
sol
utes
fro
m a
leaf
rsquos
inte
rior
Lers
ten
and
Cur
tis (1
996)
http
sw
ww
bio
sciu
texa
sed
u a
nd
Mae
da a
nd M
aeda
(198
8)
Latic
ifer
cells
Cel
ls o
r a
serie
s of
cel
ls w
hich
pro
duce
late
xFa
hn (1
990)
Pic
kard
(200
8) a
nd
Botw
ebu
wsp
Edu
Si
mpl
eSi
ngle
-cel
led
C
ompo
und
and
artic
ulat
ed
Uni
on o
f ce
lls c
ompo
und
in o
rigin
and
con
sist
of
long
itudi
nal c
hain
s of
cel
ls w
all s
epar
atin
g
cells
rem
ain
inta
ct c
an b
ecom
e pe
rfor
ated
or
entir
ely
rem
oved
Salt
glan
dsM
odifi
ed t
richo
mes
tw
o‐ce
lled
and
posi
tione
d fla
t on
the
sur
face
in r
ows
para
llel t
o th
e le
af
surf
ace
occ
ur in
Poa
ceae
Ever
t (2
006)
Tan
et
al (
2010
) O
ross
et a
l (1
985)
and
Tho
mso
n et
al
(198
8)
Cap
cel
l ndash la
rge
nucl
eus
and
expa
nded
cut
icle
Nai
doo
and
Nai
doo
(199
8)
Basa
l cel
l ndash n
umer
ous
and
larg
e ex
tens
ive
part
ition
ing
inva
gina
tions
of
plas
mal
emm
a
Nec
tarie
sFo
und
in n
ecta
rines
pro
duce
nec
tar
usua
lly a
t th
e ba
se o
f a
flow
erFa
hn (1
990)
Nic
olso
n an
d N
epi (
2005
)
and
Paiv
a (2
009)
Idio
blas
tsC
ryst
al‐c
onta
inin
g ce
llsLe
rste
n an
d H
orne
r (2
005)
Ex
ampl
e
Ra
phid
esPr
oduc
e ne
edle
‐sha
ped
crys
tals
Muc
ilage
cel
lO
ccur
in a
larg
e nu
mbe
r of
dic
ots
com
mon
in c
erta
in c
acti
slim
y m
ucila
ge p
reve
nts
evap
orat
ion
of w
ater
by
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ing
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ater
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duce
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ilage
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eed
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9sec
reto
ry9
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l
Wes
tern
et
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) and
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ovsk
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et a
l (2
010)
Oil
cells
Spec
ializ
ed c
ells
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ear
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larg
e pa
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an o
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ascu
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med
aft
er t
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ner
wal
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osite
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008)
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pbr
ittan
ica
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and
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sten
et
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)
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ses
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rical
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rega
tes
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atic
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orne
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ls in
non
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erm
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ytes
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to
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y ce
llsht
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ide
com
fac
ulty
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nbr
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gy_l
inks
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roid
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ater
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duct
ing
cells
http
w
ww
Bio
logy
‐onl
ine
org
Lept
oids
ndash P
terid
ophy
tes
Org
anic
com
poun
d‐co
nduc
ting
cells
spo
roge
nous
cel
ls p
rese
nt in
spo
rang
ia o
f so
ri
Tab
le 1
1 (
Con
tin
ued
)
An introduction to cells and their organelles 5
development is discussed in Fosket (1999) Moore and Clark (1995) Greenland
(2003) Leyser and Day (2003) and Rudall (2007)
What is the composition of cellsCertain plant components exhibit polar growth for example the tip growth of
pollen tubes (Hepler et al 2001) The tubes elongate via the fusion of Golgi‐
derived vesicles with the plasmalemma and subsequent deposition of the vesi-
clesrsquo contents into the cell wall (Taylor and Hepler 1997 Parton et al 2001 and
others as reviewed in Malho (2006a 2006b)) In 2007 Dalgic and Dane (2005)
published a diagram depicting the now known tube‐tip structural elements and
physiological processes that facilitate tube elongation The diagram represents a
Figure 12 Angiosperm shoot meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
Figure 13 Angiosperm root meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
6 Plant cells and their organelles
significant advance over the early studies of pollen tubes as it assigns function to
ultrastructural components for example signalling molecules the Rho family of
GTPases and phosphatidylinositol 45 bisphosphate appear to be localized in the
apical plasma membrane Besides pollen tubes root hairs exhibit polar growth
Cell organelles ndash an introduction
Organelles are required for plant growth development and function (Sadava
1993 Gillham 1994 Herrmann 1994 Agrawal 2011) These organelles
(Figure 17) are the loci for a myriad of physiological and biochemical processes
(Tobin 1992 Daniell and Chase 2004 ndash see individual chapters)
There are many diagrams of a generalized plant cell Some of these are available
at wwwexplorebiologycom httpwwwdaviddarlinginfoimagesplant_celljpg
Table 12 Meristems and their derivatives
Meristems Derivatives
Primary
Protoderm Epidermis
From tunica (Evert 2006)
Procambium (provascular) Primary xylem and phloem
From corpus (Evert 2006) Vascular cambium
Ground Ground tissue pith and cortex
Lateral
Vascular cambium
Fusiform initials Secondary xylem
Secondary phloem
Ray initials (Evert 2006) Ray cells
Cork cambium
Phellogen Replaces the epidermis when cork cambium initiates stem girth
increase composed of lsquoboxlikersquo cork cells which are dead at
maturity protoplasm secretes suberin some cork cells that are
loosely packed give rise to lenticels which function in gas exchange
between the air and the stemrsquos interior httpwwwBiology‐online
org Evert (2006) httpwwwvebrioSceincevunlenvirut
Periderm (Evert 2006)
Phelloderm Parenchyma cells produced on the inside by the cork cambium
Meristems are discussed by Steeves and Sussex (1989)
Table 13 Plant tissues
Tissue system
Meristematic Ground Vascular Dermal
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
An introduction to cells and their organelles 5
development is discussed in Fosket (1999) Moore and Clark (1995) Greenland
(2003) Leyser and Day (2003) and Rudall (2007)
What is the composition of cellsCertain plant components exhibit polar growth for example the tip growth of
pollen tubes (Hepler et al 2001) The tubes elongate via the fusion of Golgi‐
derived vesicles with the plasmalemma and subsequent deposition of the vesi-
clesrsquo contents into the cell wall (Taylor and Hepler 1997 Parton et al 2001 and
others as reviewed in Malho (2006a 2006b)) In 2007 Dalgic and Dane (2005)
published a diagram depicting the now known tube‐tip structural elements and
physiological processes that facilitate tube elongation The diagram represents a
Figure 12 Angiosperm shoot meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
Figure 13 Angiosperm root meristem section Source Alison Roberts Reproduced with
permission of University of Rhode Island
6 Plant cells and their organelles
significant advance over the early studies of pollen tubes as it assigns function to
ultrastructural components for example signalling molecules the Rho family of
GTPases and phosphatidylinositol 45 bisphosphate appear to be localized in the
apical plasma membrane Besides pollen tubes root hairs exhibit polar growth
Cell organelles ndash an introduction
Organelles are required for plant growth development and function (Sadava
1993 Gillham 1994 Herrmann 1994 Agrawal 2011) These organelles
(Figure 17) are the loci for a myriad of physiological and biochemical processes
(Tobin 1992 Daniell and Chase 2004 ndash see individual chapters)
There are many diagrams of a generalized plant cell Some of these are available
at wwwexplorebiologycom httpwwwdaviddarlinginfoimagesplant_celljpg
Table 12 Meristems and their derivatives
Meristems Derivatives
Primary
Protoderm Epidermis
From tunica (Evert 2006)
Procambium (provascular) Primary xylem and phloem
From corpus (Evert 2006) Vascular cambium
Ground Ground tissue pith and cortex
Lateral
Vascular cambium
Fusiform initials Secondary xylem
Secondary phloem
Ray initials (Evert 2006) Ray cells
Cork cambium
Phellogen Replaces the epidermis when cork cambium initiates stem girth
increase composed of lsquoboxlikersquo cork cells which are dead at
maturity protoplasm secretes suberin some cork cells that are
loosely packed give rise to lenticels which function in gas exchange
between the air and the stemrsquos interior httpwwwBiology‐online
org Evert (2006) httpwwwvebrioSceincevunlenvirut
Periderm (Evert 2006)
Phelloderm Parenchyma cells produced on the inside by the cork cambium
Meristems are discussed by Steeves and Sussex (1989)
Table 13 Plant tissues
Tissue system
Meristematic Ground Vascular Dermal
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
6 Plant cells and their organelles
significant advance over the early studies of pollen tubes as it assigns function to
ultrastructural components for example signalling molecules the Rho family of
GTPases and phosphatidylinositol 45 bisphosphate appear to be localized in the
apical plasma membrane Besides pollen tubes root hairs exhibit polar growth
Cell organelles ndash an introduction
Organelles are required for plant growth development and function (Sadava
1993 Gillham 1994 Herrmann 1994 Agrawal 2011) These organelles
(Figure 17) are the loci for a myriad of physiological and biochemical processes
(Tobin 1992 Daniell and Chase 2004 ndash see individual chapters)
There are many diagrams of a generalized plant cell Some of these are available
at wwwexplorebiologycom httpwwwdaviddarlinginfoimagesplant_celljpg
Table 12 Meristems and their derivatives
Meristems Derivatives
Primary
Protoderm Epidermis
From tunica (Evert 2006)
Procambium (provascular) Primary xylem and phloem
From corpus (Evert 2006) Vascular cambium
Ground Ground tissue pith and cortex
Lateral
Vascular cambium
Fusiform initials Secondary xylem
Secondary phloem
Ray initials (Evert 2006) Ray cells
Cork cambium
Phellogen Replaces the epidermis when cork cambium initiates stem girth
increase composed of lsquoboxlikersquo cork cells which are dead at
maturity protoplasm secretes suberin some cork cells that are
loosely packed give rise to lenticels which function in gas exchange
between the air and the stemrsquos interior httpwwwBiology‐online
org Evert (2006) httpwwwvebrioSceincevunlenvirut
Periderm (Evert 2006)
Phelloderm Parenchyma cells produced on the inside by the cork cambium
Meristems are discussed by Steeves and Sussex (1989)
Table 13 Plant tissues
Tissue system
Meristematic Ground Vascular Dermal
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
An introduction to cells and their organelles 7
and httpmicromagnetfsuedu The organelle contents of plant and animal
cells in common and those unique to plant cells are depicted in Table 14 The
dimensions of plant organelles are presented in Table 15 A plant organelle data-
base (PODB) has been reviewed by Mano et al (2008)
To enter a plant cell molecules must traverse both the cell wall and the fluid
mosaic plasmalemma (Singer and Nicolson 1972 Leshem et al 1991 Larsson and
Miller 1990) In contrast to the fluid mosaic model (Figure 18) of the plasmalemma
Figure 14 SEM of a pecan leaf Diagram of a leafrsquos interior is available at httppics4learning
com Source Reproduced with permission of Asaf Gal
Both day length and temperature regulate owering
Flowering is regulated by a protein hormone named origen
Leaf primordia
Includes the shoot meristem and the owers Inorescence meristem
Floral meristems generate oral organs ie sepals petals stamens and carpels
Genes occur in oral m
eristemsH
omeo
tic g
enes
enc
ode
prot
eins
Figure 15 Schematic of the floral meristem
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
H2O
CO2H2O
Sugars
Sugars
Sugarsstarch
starch or sugarstorage organ
Light energy
vapour
Starch or sugarstorage organPhotosynthesis
respiration andphotorespiration
Respiration nophotorespiration
O2
CO2
O2 H2O andmineralsenter throughroot hairs
C6H12O6
Figure 16 Diagram of angiosperm plant body Source From httpwwwmsueducourse
te8021science08plantsfoodshtml
Figure 17 Electron micrograph of a plant cell and its organelles Source Reproduced with
permission of HJ Horner
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
An introduction to cells and their organelles 9
the picketndashfence model proposes the accumulation of membrane protein anchored
in an actin network beneath the membrane (Kusumi et al 2012)
The plasmalemma is composed of water protein and lipids There are both
integral and peripheral proteins (Leshem et al 1991) The integral proteins may
be simple (classical α‐helical structure that traverses the membrane only once)
or complex (globular ndash composed of several α‐helical loops which may span the
membrane several times) Peripheral proteins can be easily isolated by altering
Table 14 Comparison of organelle contents of plant and animal cells
Organelle Animal cell Plant cell
Cell wall Absent Present
Centrioles Present Absent
Endoplasmic reticulum Present Present
Glyoxysomes Absent Present
Golgi apparatus Present Present
Microfilaments Present Present
Mitochondrion Present Present
Nucleus Present Present
Peroxisomes Present Present
Plastids Absent Present
Protein bodies Absent Present
Spindle Present Present
Vacuoles Sometimes small Present (mature
cell ndash large central)
Early discussions of plant cell organelles occur in Hongladarom et al (1964) Pridham (1968) Reid
and Leech (1980) and Tobin (1992)
Table 15 Dimensions of subcellular organelles
Organelles Dimension
Chloroplast 4ndash6 microm in diameter
Golgi apparatus Individual cisternae 09 microm
Coated vesicles 50ndash280 microm in diameter
Microbodies 01ndash20 microm in diameter
Microtubules 05ndash10 microm in diameter
Mitochondria 1ndash10 microm
Nuclear envelope pores 30ndash100 microm in diameter
Nucleus 5ndash10 microm in diameter
Peroxisome 02ndash07 microm
Plasmodesmata 2ndash40 microm in diameter
Primary wall 1ndash3 microm
Protein bodies 2ndash5 microm in diameter
Vacuoles 30ndash90 of cell volume
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
10 Plant cells and their organelles
the ionic strength or pH of the encasing medium The transport proteins are
pumps carriers or chemicals (see section on membrane transport) The lipids are
electro-negative and anionic phospholipids sphingolipids (Figure 19) chloroplast‐
specific glycerolipids and sterols (Table 16)
Lipid rafts are specialized phase domains containing sterols and sphingolipids
which may be important in signal transitions (Gray 2004 Furt et al 2007
Grennan 2007 Mongrand et al 2004) Caveolae which give rise to clathrin‐
coated vesicles (Brodsky et al 2001) are anchored multifunctional platforms in
lipids (Van Deurs et al 2003 Patel and Insel 2009)
The organization of the caveolae (Bastani and Parton 2010) in the plasma-
lemma and clathrin‐coated vesicles (Samaj et al 2005) is presented in Figure 110
The current discussion focuses on membrane transport mechanism Plants can
internalize certain molecules by endocytosis via invaginations of the plasmalemma
yielding clathrin‐coated vesicles (Figure 111 Holstein 2003) which become the
endosome (Low and Chandra 1994 Battey et al 1999 Šamaj et al 2006)
Proteins involved in clathrin‐dependent endocytosis appear to be clathrin adaptor
proteins and two adaptins (Pearse and Robinson 1990 Šamaj et al 2006) Plant
endocytosis and endosomes (Contento and Bassham 2012) seem to be significant
in auxin‐mediated cellndashcell communication gravity responses stomatal move-
ments cytokinesis and cell wall morphogenesis (Šamaj et al 2006)
Ion channels
Plasma membranes contain potassium (K+) calcium (Ca++) and anion channels
(Roberts 2006) Voltage‐gated ion channels are transmembrane ion channels acti-
vated by changes in electrical potential Gating is the precise control of ion channel
opening (Krol and Trebacz 2000) An example of an ion channel is the K+ the
Fluid mosaic model of the plasmalemma
Consists of a lipid bilayer in which globular proteins are embedded There are two types of proteins integraland peripheral Oliogsaccharides (2ndash20 monosaccharides) can be attached to the integralproteins Phospholipids from the bilayer with a polar head on the outside and non-polar tails on theinside
Fence model of the plasmalemma
There is a membrane skeleton with skeleton-anchored proteins and transmembrane proteins projectedoutwards into the cytoplasm Cytoplasmic domains of proteins collide with the actin skeleton yieldingtemporary con nement of the transmembrane proteins The membrane can contain lipid rafts andrelated caveolae invaginations The rafts are combinations of proteins and the lipids which may function insignalling sphingolipids are prevalent in the rafts
Picket model of the plasmalemma
Phospholipids can also be con ned by the membrane skeleton Some investigators combine the fenceand picket models
Figure 18 Top Fluid mosaic model of the plasmalemma Middle Fence model of the
plasmalemma Bottom picket model of the membrane
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
An introduction to cells and their organelles 11
inwardly potassium channel This type of channel possesses a positive charge in
the cell Stomatal pore movements are mediated by a rise in intracellular K+ and
anion contents of guard cells (Schroeder and Hagiwara 1989) Another example
is the adenosine triphosphate (ATP) binding cassette transporter or ABC trans-
porter These transport toxic substances from the cell or into the vacuole These
Figure 19 Structures of (a) phospholipids and (b) sphingolipids
O
Phosphatidic acid Phosphatidylethonolamine Leeithin
Phosphatidylserine Phosphatidylinositol 1-Lysoleeithin
Glycerol-3 phosphate
Phosphatidate
Phosphatidylcholine(leeithin)
OH
OO
O
O
O
O
OH
OH
R1
R2
P
P
OO
O
O O
O
R1
R2 O
OH
P NH2
CH3
OO
OO
O
OO
R1
R2
OH
PN
CH3
CH3CH3
+
OOO
O
OOO O
OOO O
OO
+
+
+
+
+O
OOO
O
P
R1
R2 OHOH
OH
OH
OH
P
OO
OO
O
OO
HO
PN
+
OO
O
OO CH3
CH3
CH3OH
HO
H
HOCH
CHCH
CH3
CH2CH2
H3C
P
CCCC
N
CH2
CH2
CH2
H2CH2C
H2C
OO
O
O O
O
O O
R1
R2
PNH2OH
OH
(a)
HHO
H H
H
H
H H
HH
CH3
CH3
H3C
H3C
CH3
CH3
Alpha-spinasterol
29 sterol (C29H48O)
isolated from `Phytolaccaacute
httpwww3dmetdnaaffecgojpbin2show_dataeacc-B02450
Brassicasterol
28 sterol (C28H46O)
synthesized by oilseed rape
and several unicellular algae
httpenwikipediaorgwikiBrassicasterol
HO
HO(b)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
12 Plant cells and their organelles
transporters are composed of four core domains two cytosolic nucleotide‐binding
proteins and two transmembrane domains (Malmstrom 2006)
Besides cation channels there are anion channels regulated by voltage but
their activity is also influenced by Ca++ ATP phosphorylation or membrane
stretching (Tyerman 1992) Anion plasma membrane channels function as
efflux channels when they are open
Table 16 Composition of certain cellular membranes
Chemical composition
Fatty acyl groups in membrane lipids
160 161 t‐161 163 180 181 182
α183 δ183 184 220 221 240 241
Electroneutral phospholipids Phosphatidylcholine phosphatidylethanol
phosphatidylethanolamine
Anionic phospholipids Phosphatidylserine phosphatidylglycerol
phosphatidylinositides
Lyo‐phospholipids Cerebrosides
Sphingolipids Galactolipids sulpholipids
Chloroplast‐specific glycerolipids Diphosphatidylglycerol and monophosphatidylglycerol
Mitochondrial phospholipids
Sterols Sitosterol
Campesterol
Stigmasterol
Unusual sterols
Cycloartenol
Cholesterol minute quantities
Sterol glycosides
Lanosterol Pathogenic fungal membranes
Water
Extramembrane water Membrane is a bilayer sandwiched between two layers
of water
Water located within the bilayer which is attached to
or in approximate contact with the expanses of
membrane constituents
Proteins May cross the membrane once or several times and are
linked either electrostatically or by means of biophysical
lipophilicity to the inner domains of the bilayer
Integral proteins
Simple integral proteins Classic α‐helical structure that traverses the membrane
only once
Complex integral proteins Globular ndash comprised of several α‐helical loops that
may span the membrane several times
Peripheral proteins Associated with only leafletndasheasily isolated by altering
ionic strength or pH of the encasing medium
Transport proteins Pumps carrier and channel
Source From Leshem et al (1991)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
An introduction to cells and their organelles 13
Figure 110 Depictions of a (a) lipid raft (b) caveolae and a clathrin‐coated vesicle Source
Reproduced with permission of Caveolae and Clathrin Vesicle
CytosolCholesterol
Protein with longertransmembrane domain
Normal trans-Golginetwork membrane
Protein with shorttransmembranedomain cannotenter lipid raft
GPI-achoredprotein
Lectins
Glycolipids
Lumen
(a)
Integral proteins excludedfrom transport vesicles
Exoplasmic face
Cytosolic face
Assemblyparticle
Fibrousclathrincoat
GTP
GDP
Dynamin
Clathrin-coatedvesicle
(b)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
14 Plant cells and their organelles
proton pumps
The transport of a substance against its electro channel gradient requires energy
generated by ATP‐proton pumps (Briskin and Hanson 1992 Evert 2006) One
such pump is the V‐ATPase found in both the plasmalemma and the tonoplast
(Barkla and Pantoja 1996 Vinay et al 2009) The H+‐ATPase in the plasma-
lemma is the P‐ATPase which forms electrochemical gradients (Elmore and
Coaker 2011) Mitochondria and chloroplast membranes possess F‐ATPases
Water channels
Aquaporins are channel proteins which exist in the plasmalemma in intracellular
spaces (Maurel et al 2008) These proteins permit water to move freely but
exclude ions and metabolites (Chrispeels and Maruel 1994 Muller et al 2007)
Intermediate endosome
δ-TIP
Late endosomePVC
Vacuole
ARA6
ARA7RHA1
AtVAMP727
AtSKD1
PM ATPase PM receptor
AtSYP21AtSYP22
VSR
AtALEU
GNOMBFA
PIN1+NPAndashbinding protein
TGNAtSYP61
Golgi
ERCPCR
SVP ndash a syntaxinGNOM ndash Plant-specic protein that participates in ADP-ribosylationESCRT ndash protein endosomal sorting complexRHA ndash a member of the Rab GTPases function in trafcking pathwaysARA6 ndash a member of the Rab GTPasesSYP ndash a SNARE component of the late endosomeVSR ndash vacuolar sorting receptorSKD ndash vacuolar protein suppressorUbiquitylation ndash signal that regulates the cell surface expression
Figure 111 Diagram of plant endocytosis Source Reproduced with permission of M Otegui
University of Wisconsin
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
An introduction to cells and their organelles 15
providing for buffering osmotic fluctuations in the cytosol Aquaporins are major
intrinsic membrane proteins which are composed of four subunits each of
which comprises six transmembrane‐spanning helices Aquaporins are encoded
by multiple gene families (Johansson et al 1998)
Carriers
Carriers are unitransporters and co‐transporters (Evert 2006) Unitransporters
transport only one solute from one side of the membrane to the other On the
contrary co‐transporters transfer one solute with the simultaneous or sequential
transfer of another solute A thorough discussion of membrane transport
processes occurs in Malmstrom (2006)
Organelle structure and function can be influenced by a variety of environ-
mental parameters which affect plant growth A discussion of parameters is pre-
sented because of the increasing pollution of the earthrsquos atmosphere and
ecosystem In addition global climate change is a current issue of urgent con-
cern (Dashek and McMillin 2009)
Both major and minor elements are required for growth and development
(Table 17) Metals and metalloids at elevated levels can result from mining
(Dashek and McMillin 2009) What effects do these levels have on the structure
and function of cellular organelles (See Lepp 1981 Medioini et al 2008 Yusuf
et al 2011 see also Table 18)
Elevated levels of SO2 CO
2 NO
2 and O
3 (Treshow and Anderson 1989) can
occur in the atmosphere as a result of industrial and contemporary activities
Table 19 presents the effects of certain gases (Bell and Treshow 2002) on the
structure and function of organelles Of special interests are the increasing levels
Table 17 Major and minor elements required for plant growth and development
Element mgkg Minor or major
Nitrogen N 15 000 Major
Potassium K 10 000 Major
Calcium Ca 5 000 Major
Magnesium Mg 2 000 Major
Phosphorus P 2 000 Major
Sulfur S 1 000 Major
Chlorine Cl 100 Minor
Iron Fe 100 Minor
Boron B 20 Minor
Manganese Mn 50 Minor
Zinc Zn 20 Minor
Copper Cu 6 Minor
Molybdenum Mo 01 Minor
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)
16 Plant cells and their organelles
of CO2 in the atmosphere which many scientists believe causes global warming
(Dashek and McMillin 2009) Table 110 offers the effects of sublethal and lethal
temperatures on organelles Franklin and Wigge (2014) discuss the effects of
temperature on plant development Other environmental parameters which can
Table 18 Toxic metals and metalloids
Metal or metalloid
Toxic level effects References
Aluminium Affects root cells of plasmalemma Mossor‐Pietraszewska (2001)
Arsenic Pale green to yellow lesions on leaves and
necrosis of leaves
Treshow and Anderson (1989)
Defoliation
Impaired nitrogen metabolism
Needle abscission
Cadmium General chlorosis Treshow and Anderson (1989)
Saadati et al (2012) and Khateeb
(2014)
Reduced photosynthesis
Reduced transpiration toxic effects ndash changes
in proline levels changes in lipid peroxidation
and seed germination
Copper Interference with normal metabolic reactions Treshow and Anderson (1989)
and Shah et al (2001)Blocks specific enzymatic reactions
Chromium Contamination Treshow and Anderson (1989)
and Antonovics et al (1971)Can promote white dead patches on leaves
Lead Condensation of nuclear chromatin decrease
in germination of two Brassica cultivars
Rout and Das (2003) and
Hosseini et al (2007)
Nickel Dilution of nuclear membrane Seregin and Kozhernikova (2006)
Zinc Disruption of cortical cell Rout and Das (2009)
Table 19 Effects of environmental pollutants on organelles
Elevated CO2
Stomatal openings reduce as CO2 increases Woodward et al (1991)
Affects both primary and secondary meristems
of shoots and roots alternation of leaf size and
anatomy increased branching and stem
diameter
Pritchard et al (1999)
Increase in the number of mitochondria and
amount of chloroplast stroma thylakoid
membranes
Griffin et al (2001)
Stomatal densities decrease in two species of
Spartia
Lammertsmaa et al (2011)
Acid rain Leaching of nutrients on tree needles damages
surfaces of needles and leaves and reduces a
treersquos ability to withstand cold
Godbold and Huumlttermann
(1994) Schulze et al (2000)
and White and Terninko (2003)
Nitric oxide Necrotic lesions marginal chlorosis Lamattina and Polacco (2007)
Ozone and its
derivatives
Changes in metabolism Roshchina and Roshchina (2003)