Transpiration: Removal of water from aerial parts of plants (particularly leaves) in the form of water vapor is called Transpiration. It occurs through stomata, cuticle, or lenticels of plants.
Stomata: It is the specialized epidermal structure of the plant is responsible for the exchange of gases between the plant and the environment.
Starch - sugar interconversion: Starch sugar interconversion is a slow process which is responsible for rapid stomatal movement.