Describe the structure of stomata.

Explanation

The epidermis of leaves and green stems possess many small pores called stomata. The length and breadth of stomata is about `10 - 40 mu` and `3-10 mu` respectively. Mature leaves contain between 50 and 500 stomata per `mm^(2)`. Stomata are made up of two guard cells, special semilunar of kidney-shaped living epidermal cells in the epidermis. Guard cells are attached to surrounding epidermal cells known as subsidiary cells or accessory cells. The guard cells are joined together at each end but they are free to separate to form a pore between them. The inner wall of the guard cell is thicker than the outer wall. The stome opens to the interior into a cavity called sub-stomatal cavity which remains connected with the intercellular spaces.