Transpiration is the evaporative loss of water by plants. It occurs mainly through the stomata in the leaves. Exchange of oxygen and carbon dioxide in the leaf also occurs through stomata. Normally stomata are open in the day time and close during the night. The cause is a change in the turgidity of the guard cells. The inner wall of each guard cell towards the stomatal aperture is thick and elastic. When turgidity increases, the thin outer walls bulge out and force the inner walls into a crescent shape. The opening of stoma is also aided due to the orientation of the microfibrils in the cell walls of the guard cells.
Factors affecting Transpiration:
Temperature, light, humidity and wind speed. Importance of Transpiration: Transport of liquids and minerals is facilitated because of transpiration.
