Is there a general mechanism to explain the opening and closing of stomata? Justify your answer.

Solution:

The opening and closing of stomata depend on the turgor pressure, caused by the osmotic flow of water in the guard cells. When the guard cells are turgid, they expand resulting in the opening of stomata. When the guard cells lose water, they become flaccid leading to stomatal closure. Stomata normally open when the light strikes the leaf and close during the night.