Structure of stomata

Fig: Structure of stomata

Stomata are minute pores in the epidermal cells through which gaseous exchange takes place. They are found mainly in leaves but also in stem, flowers and fruits.Each stomata is surrounded by two guard cell. In dicot , guard cells are bean shaped but in monocot. , they are dumb bell shaped. Te guard cells are surrounded by epidermal cells called subsidiary cells. The cell wall of guard cells around the stomatal pore are thick and inelastic due to the presence of secondary cellulose layer. Rest of the wall is thin and elastic. Guard cell has a thin layer of cytoplasm and a large central vacuole. It’s cytoplasm contain a nucleus and no. of chloroplast.