Structure Of leaf
1. Isobilateral Leaf
2. Dorso-ventral Leaf
1. Structure Of Monocot Leaves Or Isobilateral Leaf -
Thickness of cuticle is equal on both surface.
Amphistomatic leaves that means, stomata present on both sides are equal in number.
Mesophyll is not differentiated into pollisade and spong tissue while it is completely made up of spongy tissue.
So pellisade tissue are absent in it. example, leaves of monocot plant.
2. Structure Of Dorso -Ventral Leaf (Dicot Leaf) -
Three Main Parts Are Differentiated In It -
A. Epidermis
B. Mesophylll
C. Vacular Bundles
Leaves Are Present At Right Angle On The Stem.
Cuticle Is Present on both surfaces but cuticle of upper surface is more thick.
These are mostly hypostomatic leaves that means stomata present on lower surface.
Some leaves are amphi - stomatic leaves that means stomata present more on lower surface as compared to upper surface.
Mesophyll of these leaves is divided into two types -
1. Pellisade
2. Spongy Tissue
2. Spongy Tissue -
A. Epidermis
B. Mesophylll
C. Vacular Bundles
Leaves Are Present At Right Angle On The Stem.
Cuticle Is Present on both surfaces but cuticle of upper surface is more thick.
These are mostly hypostomatic leaves that means stomata present on lower surface.
Some leaves are amphi - stomatic leaves that means stomata present more on lower surface as compared to upper surface.
Mesophyll of these leaves is divided into two types -
1. Pellisade
2. Spongy Tissue
1. Pellisade -
It is formed by parenchyma tissue.
It is present towards upper surface and have more chloroplast.
2. Spongy Tissue -
It is also made up of parenchyma cell.
It present towards lower surface and have less chloroplast.
These are spongy in nature. Example, leaves of duvet.
Vascular Bundles Of Both Leaves -
Similar type of vascular bundles found in both leaves.
Vascular bundles are conjoint, colateral and closed. So, secondary growth is not present.
Leaves are devoid of endodermis and pericycle.
Vascular bundles are surrounded by a single - celled layer called bundle sheath.
Bundle - Sheath in c4 plants is collenchyma and have chloroplast but remaining all plants have parenchymatous or sclernchymatous bundle sheath.
Secondary Growth -
The Growth Of Roots and stem in length with the help of apical meristem is called primary growth.
Most of dicot plants exhibits an increase in girth.
This increment is called secondary growth.
Tissues which involved in 2
° growth are the two lateral meristem.
1. Vascular Cambium -
The Merismetic Layer which responsible for cutting off vascular tissue. xylem and phloem is called vascular cambium.
In the young stem, it is present in patches as a single layer between the xylem and phloem.
After sometime it forms a complete ring.
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