Write a note on the Epidermal Tissue system.

(N/A) $\rightarrow$ On the basis of their structure and location,there are three types of tissue systems: Epidermal tissue system,ground or fundamental tissue system,and vascular or conducting tissue system.
$\rightarrow$ Epidermal Tissue System: The epidermal tissue system forms the outermost covering of the whole plant body and comprises epidermal cells,stomata,and epidermal appendages (trichomes and hairs).
$\rightarrow$ The epidermis is the outermost layer of the primary plant body. It is made up of elongated,compactly arranged cells which form a continuous layer.
$\rightarrow$ Epidermis is usually single-layered. Epidermal cells are parenchymatous with a small amount of cytoplasm lining the cell wall and a large vacuole.
$\rightarrow$ The outside of the epidermis is often covered with a waxy thick layer called the cuticle,which prevents the loss of water.
$\rightarrow$ Cuticle is absent in roots.
$\rightarrow$ Stomata are structures present in the epidermis of leaves. Stomata regulate the process of transpiration and gaseous exchange.
$\rightarrow$ In dicot plants,each stoma is composed of two bean-shaped cells known as guard cells.
$\rightarrow$ In grasses,the guard cells are dumb-bell shaped. The outer walls of guard cells (away from the stomatal pore) are thin and the inner walls (towards the stomatal pore) are highly thickened.
$\rightarrow$ The guard cells possess chloroplasts and regulate the opening and closing of stomata.
$\rightarrow$ Sometimes,a few epidermal cells in the vicinity of the guard cells become specialized in their shape and size and are known as subsidiary cells.
$\rightarrow$ The stomatal aperture,guard cells,and the surrounding subsidiary cells are together called the stomatal apparatus.
$\rightarrow$ The cells of the epidermis bear a number of hairs. The root hairs are unicellular elongations of the epidermal cells and help absorb water and minerals from the soil.