8. What is stomatal apparatus? Explain the structure of stomata with a labelled diagram.
Stomata are tiny pores or holes found to be present in the epidermis of leaves. The major function of these stomata is to regulate the process of transpiration and gaseous exchange. The stomatal pore remains surrounded by specialised cells called guard cells which in turn are surrounded by subsidiary cells.
The stomatal pore, guard cells and the surrounding subsidiary cells together constitute the stomatal apparatus.
The gaseous exchange is maintained by guard cells. In dicots, guard cells are bean-shaped while in monocots, guard cells are dumbbell shaped.