Describe the structure of T.S dicot leaf.

Explanation

The T.S of dicot leaf contains
(i) Epidermis- Upper and Lower
(ii) Mesophyll
(iii) Vascular bundles
(i) Epidermis: The leaf is dorsiventral it has upper and lower epidermis.
(a) Upper Epidermis: Made up of single layer of tightly packed parenchyma cells. Cuticle is thicker than the lower epidermis.
(b) Lower Epidermis: Made up of single layer of parenchymatous cells with thin cuticle.
Stomata are more in lower epidermis. Used for transpiration and gaseous exchange.
(ii) Mesophyll: The region between upper and lower epidermis is called mesophyll. It is differentiated into palisade and spongy parenchyma.
(a) Palisade parenchyma: Present below the upper epidermis cells are elongated. Cells do not have intercellular spaces More number of chloroplast present. Function is photosynthesis.
(b) Spongy parenchyma: Present above the lower epidermis.Cells are irregular shaped. Cells have intercellular spaces less number of chloroplast is present. Function is gaseous exchange.
(iii) Vascular bundles: Vascular bundles are conjoint, collateral and closed. Vascular bundles are surrounded by a compact layer of parenchymatous cells. These are called Bundle sheath. Xylem is present towards the upper epidermis. Phloem is present towards the lower epidermis.