Question

Question 29
The opening and closing of the stomatal pore depends upon

(a) Oxygen
(b) Temperature
(c) Water in the guard cells
(d) Concentration of ${\text{CO}}_2$ in stomata

Answer 1

(c) Water in the guard cells

Guard cells are specialized cells present in the epidermis of leaves, stems and other organs that are used to control gas exchange. The guard cells are produced in pairs with a gap between them that forms a stomatal pore. The stomatal pores are largest when water is freely available and the guard cells are turgid. The stomatal pores are closed when water availability is critically low and the guard cells become flaccid.