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 stems, flowers,s, and fruit s. Each stomata is surrounded by two guard cells. In dicot, guard cells are bean-shaped but in monocot. , they are dumbbell-shaped. The guard cells are surrounded by epidermal cells called subsidiary cells. The cell walls of guard cells around the stomatal pore are thick and inelastic due to the presence of a secondary cellulose layer. The rest of the wall is thin and elastic. Guard cell has a thin layer of cytoplasm and a large central vacuole. Its cytoplasm contains a nucleus and no. of the chloroplast.