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.
- Upper Epidermis : Made up of single layer of tightly packed parenchyma cells. Cuticle is thicker than the lower epidermis.
- 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.
- Palisade parenchyma: Present below the upper epidermis cells are elongated. Cells do not have intercellular spaces. More number of chloroplast present. Function is photosynthesis.
- 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.