Explain the theory of photosynthesis in guard cells obeserved by Von Mohl with its demerits.

Explanation

Von Mohl (1856) Observed that stomata open in light and close in the night .According to him,chlorroplasts present in the guard cells Photosynthesize in the presence of light resulting in the production of carbohydrater (sugar) which increase osmotic pressure in guard cells.It leads to the entry of water from other cell and stomatal aperture opens.The above process vice versa in night leads to closure of stomata.
Demerits:
(i)Chloroplast of guard cells is poorly developed and incapable of performing photosynthesis.
(ii) The guard cells already prossess much amount of stored of stored sugars.