Question

Explain the theory of photosynthesis in guard cells and state its demerits.

Answer 1

Theory of Photosynthesis in guard cells:

Von Mohl (1856) observed that stomata open in light and close in the night. According to him, chloroplasts present in the guard cells photosynthesize in the presence of light resulting ‘ in the production of carbohydrate (Sugar) which increases osmotic pressure in guard cells.

It leads to the entry of water from other cells and the stomatal aperture opens. The above process vice versa at the night lead to the closure of stomata.

Demerits

1. The chloroplast of guard cells is poorly developed and incapable of performing photosynthesis.
2. The guard cells already possess much amount of stored sugars.