How does opening and closing of stomata take place? Class 10 Biology Respiration
Answers
Transpiration is the process in which evaporation of water from plants takes place. It occurs mainly at the surface of leaves when the stomata of plant open for passage of carbon dioxide and oxygen during photosynthesis.
The water is converted in to vapour in the presence of sunlight and passes out through pores which are present in the stomata on the surface of leaf.
Guard cells play an important role in open and closing of stomata. Guard cells are the pair of cells which surround the stomata. They control the opening and closing of the stomata.
This opening and closing is regulated by various signals such as light, temperature, CO₂ concentration in the leaf etc.
In response to factors such as sunlight, low carbon dioxide concentration in the leaf etc. solutes such as sugars, K⁺, Cl⁻, etc are actively transported or pumped into the guard cells.
This lowers the water potential and thus induces the water influx across the cell membrane. The water inflates the guard cells into the kidney-bean shaped cells and thus opens the stomata.
And when the guard cells lose water, which causes the cells to become flaccid, which results in the stomatal opening to close.
Transpiration rates increase, when stomata are open, and it decreases when it is closed.