Why causes water to leave plants on dry summer days?

1 Answer
Jan 28, 2018

The loss of water vapours from the stomata of leaves to the atmosphere on a dry summer day is due to the process of transpiration.


The loss of water from the surface of leaves to the atmosphere is termed transpiration. It mainly occurs through the stomata, though transpiration occurs through general surface as well.

Each stoma is surrounded by two kidney -shaped guard cells. The changes in the turgidity of guard cells control the opening and closing of stomata.

Stomata remain open during day time and close at night. At night when the stomata are closed, the air in the sub-stomatal cavity becomes saturated.

During the day, stomata open. The water vapours move from substomatal cavity into the atmosphere due to difference in vapour pressure, as the water vapours move from higher vapour pressure to the lower vapour pressure.