Plant structure - cells, tissue, organisation & growth Leaves and photosynthesis
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Transcript of Plant structure - cells, tissue, organisation & growth Leaves and photosynthesis
Plant structure- cells, tissue, organisation & growth
Leaves and photosynthesis
C4 photosynthesis
CAM photosynthesis
Plant water relations
Plants and nutrients
Plant reproduction- asexual- sexual reproduction
- pollination- seed dispersal
Shoo
t sy
stem
Root
sys
tem
Taproot
Lateral roots
Shoo
t sy
stem
Root
sys
tem
Taproot
Lateral roots
Leaves
Stem
Shoo
t sy
stem
Root
sys
tem
Taproot
Lateral roots
BranchLeaves
Stem
Shoo
t sy
stem
Root
sys
tem
Taproot
Lateral roots
Apical bud
BranchLeaves
Stem
Shoo
t sy
stem
Root
sys
tem
Lateral bud
Taproot
Lateral roots
Apical bud
Branch
NodeInternode
Leaves
Lateral bud
Stem
NodeSh
oot
syst
emRo
ot s
yste
m
Basic functions of roots, stems and leaves:
Roots
Roots:• Find and absorb water• Find and absorb nutrients• Host symbionts• Anchorage and support• Attachment• Photosynthesis• Storage• Breathing or ventilation (mangroves)• Reproduction
Absorbing water and nutrients
Host symbionts
Roots of pea plant
Nodules
Anchorage and support
Attachment
Photosynthesis!
Storage
pneumatophores
Asexual reproduction
Stems
Transport and support.
Cactus stems store water, photosynthesize.
Stolons produce new individuals at nodes above ground.
Rhizomes produce new individuals at nodes below ground.
Tubers store carbohydrates.
Thorns provide protection.
Leaves Intercept lightFix CO2
Storage• Food• Water
SupportProtection (spines)Collect nutrients
• Animals• Leaves and compost
Reproduction• Asexual• Sexual (pollination)
Transport of water, sugar, and nutrients through vascular tissue
CO2
Sunlight
Water
Nutrients(such as N, P, K)
Shoo
t sys
tem
Root
sys
tem
Plant structure- cells, tissue, organisation & growth
Leaves and photosynthesis
C4 photosynthesis
CAM photosynthesis
Plant water relations
Plants and nutrients
Plant reproduction• asexual• sexual reproduction
- pollination- seed dispersal
Growth
Determinate growth
Growth
Determinate growth
Indeterminate growth
Growth
Determinate growth
Indeterminate growth
Growth
Determinate growth
Indeterminate growth
Vascular tissue
(b) Close-up of root tip
Ground tissue
Epidermal tissue
Apical mersitem
Sloughed-off root cap cells
Root cap
Root hair
Zone
of
Cellu
lar
Mat
urat
ion
Zone
of
Cellu
lar
Elon
gati
on
Zone
of
Cellu
lar
Div
isio
nLateral root
(a) Longitudinal section of root segment
mucilage
Primary Growth
Leaf primordia
Apical meristem at tip of shoot
Apical meristem in lateral bud
Primary Growth
Primary growth
Cross section of a eudicot stem
Epidermis
Cortex
Pith (ground tissue)
Vascular bundle
Secondary Growth
Detailed view of vascular bundle in a eudicot
Epidermis
Collenchyma
Phloem
Xylem
Cambium
Secondary meristem = cambium
Secondary meristem = cambium
Cylinders the length of root or stem
Secondary meristem = cambium
Cylinders the length of root or stem
Increase width of stems and roots
Vascular cambium adds cells on inside and outside
Woody stems contain two lateral meristems.
Cork cambium adds cells to the outside
Vascular cambium adds cells on inside and outside
Woody stems contain two lateral meristems.
Wood and bark contain a variety of cells and tissues.
Secondary phloemBark
Wood
Parenchyma cells (in rays)
Vascular cambium
Cork cambiumCork
Secondary xylem
Gro
wth Di
visio
nDi
ffere
ntia
tion
Divi
sion
Diffe
rent
iatio
nDi
visio
n Diffe
rent
iatio
n
Time
Secondary phloem
Vascular cambium
Secondary xylem
Heartwood and sapwood have different functions.
Heartwoodprovides structural support but no longer transports water
Sapwoodtransports water
Bark
Growth rings result from variation in cell size.
One growth ring
Early wood
Late wood
Increment borer cuts core from trunk.
Core samples from three nearby trees
These samples are lined up by year; notice similar ring patterns in trees from the same area