Question

Why plants keep their stomata closed at night?

Answer 1

Stomata:

1. Stomata are the tiny openings present on the surface of leaves.
2. They help in the exchange of gases and water in the form of vapours.
3. Their opening and closing is regulated by guard cells.

Stomata remain closed at night because of the following reasons:

1. Plants lose the majority of their water through stomata.
2. Thus, they close their stomata at night to prevent excess loss of water through them.
3. Stomata can not be closed in the daytime, because the plant has to intake carbon dioxide for the process of photosynthesis.
4. Guard cells imbibe water during the night time to become turgid and close the stomatal opening.