Anatomy

Stem Root Leaves Organs 1-Young dicot stem 2- Monoct stem 3- Old dicot stem Root 1- young dicot root 2- monocot root 3- old dicot root Leaves

Identifying Stems and Roots Diagnostic: 1- V.B. are of radial type 2- xylem is always exarch ( protoxylem is located near the periphery of the V.B.) 3- Absence of stomata and cuticle Characteristic : root stem pith small or absent small relative to pith pith and cortex  

Root anatomy Ground tissue Cortex 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 .

Give rise to lateral root only Monocot root Dicot. root Charater Give rise to lateral root only Give rise to lateral roots and secondary meristems pericycle Numerous , 20 From 2-8 V.B. absent Appear later as a secondary meristems Cambium Well developed Small or absent Pith

Endodermis Casparian strips

young dicot root pith cortex Starch Endodermis phloem Metaxylem protoxylem pith

monocot root pith epidermis cortex Starch Endodermis phloem Metaxylem protoxylem pith

Old dicot. Root Look at key board

old dicot root Cork (phellem) Cork cambium (phellogen) Phelloderm 2ry phloem Medullary rays Vascular cambium 2ry xylem

Stem Root Leaves Organs 1-Young dicot stem 2- Monoct stem 3- Old dicot stem Root 1- dorsiventral dicot leaves 2- isobilateral dicot leaves 3- monocot leaves 1- young dicot root 2- monocot root 3- old dicot root Leaves

Leaf anatomy Vascular tissue Epidermis Ground tissue ( Mesophyll ) 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 Epidermis Hybodermal layer Palisade Spongy tissue Collenchyma Pericyclic fibers Phloem Metaxylem Protoxylem

Epidermis Palisade Spongy tissue

isobilateral dicot leaves Epidermis Palisade Spongy tissue Collenchyma Pericyclic fibers Phloem xylem

monocot leaves Epidermis Hybodermal layer (sclerenchyma) Ground tissue (parenchyma) Bundle sheath (fibers) Phloem Metaxylem Protoxylem Closed collateral V. B.

Practical work : We will do transverse section in a leaf : tools  razors  Slides and covers  Pith

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