Anatomy

Organs

StemRoot

Leaves

1-Young dicot stem2- Monoct stem3- Old dicot stem

1 -young dicot root2 -monocot root3 -old dicot root

Identifying Stems and Roots Diagnostic:

Characteristic:

stemroot

pith and cortexsmall relative to pithpith small or absent

1 -V.B. are of radial type2 -xylem is always exarch ( protoxylem is located

near the periphery of the V.B(.3 -Absence of stomata and cuticle

Root anatomy Dermal tissue ( piliferous layer )One layer , no stomata , no cuticle , the outer wall may extend into root hair

Ground tissue

Cortex Parenchymatous ( dicot.) , some of them sclerenchyamtous (monocot.)Last layer of cortex termed as Endodermis which characterized by presence of casparian strips

{casparian strips : deposits of suberin and lignin on radial wall only Dicot.

On radial +inner tangential Monocot .

CharaterDicot. rootMonocot root

pericycleGive rise to lateral roots and

secondary meristems

Give rise to lateral root only

V.B.From 2-8Numerous , 20

CambiumAppear later as a secondary meristems

absent

PithSmall or absent Well developed

EndodermisCasparian strips

young dicot rootcortex Endodermis Metaxylem

protoxylem

phloem

pith

Starch

monocot rootcortex Endodermis Metaxylem

protoxylemphloem

pith

Starch epidermis

Old dicot. Root

Look at key board

old dicot root

Cork (phellem)Cork cambium (phellogen)Phelloderm2ry

phloemMedullary raysVascular cambium2ry

xylem

Organs

StemRoot

Leaves

1-Young dicot stem2- Monoct stem3- Old dicot stem

1 -young dicot root2 -monocot root3 -old dicot root

1 -dorsiventral dicot leaves2 -isobilateral dicot leaves

3 -monocot leaves

Leaf anatomy Epidermis Upper and lower surface , stomata on both sides

Ground tissue ( Mesophyll )

Specialized photosynthetic tissue In Dicot. Divided into

palisade Below epidermis and perpendicular to it , contain chloroplasts.

spongy tissue Loosely arranged , much less chloroplast than palisade.In Monocot.

Mesophyll cells all are alike not diffrantiated into palisade and spongy

Vascular tissue

Main V.B . In the center ( midrib ) , type of V.B . As the same of stem.

dorsiventral dicot leaves

EpidermisHybodermal layer

PalisadeSpongy tissueCollenchymaPericyclic fibersPhloemMetaxylemProtoxylem

EpidermisPalisadeSpongy tissue

isobilateral dicot leaves

Epidermis Palisade

Spongy tissueCollenchyma

Pericyclic fibersPhloemxylem

monocot leavesEpidermisHybodermal layer

(sclerenchyma (Ground tissue

(parenchyma(Bundle sheath

(fibers(PhloemMetaxylemProtoxylemClosed collateralV. B.

Practical work: We will do transverse section in a leaf:

tools razors

Slides and covers

Pith

Thank you

Good luck

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