The evaporation of water from aerial parts of plants is known as transpiration.
The rate of transpiration is affected by the following environmental factors.
It is one of the most important factors because it regulates the opening & closing of stomata. The stomata remain wide open during day time, as a result transpiration takes place through them but at night they are closed.
The increase in temperature increases the rate of transpiration by increasing the rate of evaporation of water from the cell surface.
Transpiration decreases with the increase in humidity (moisture of air) and increases with the decrease in humidity. It means that transpiration can only take place when the atmosphere is partially saturated or dry.
The increase in the wind velocity increases the rate of transpiration through a reduction in the density of the air.Low atmospheric pressure increases the rate of transpiration through reduction in the density of the air.
1) By active transpiration a suction force the transpiration pull is created which helps in upward movement of water and minerals.
2) It also increases the rate of transpiration.
3) It helps the evaporation of excess amounts of water.
4) It maintains a suitable temperature and prevents overheating.
5) It facilitates the ascent of sap.
6) It brings about the closing and opening of stomata which indirectly influences the process of photosynthesis and respiration.
7) Excessive loss of water from aerial parts also results in dehydration leading to the health of plants in extreme condition.
