name the factors that affect the rate of transpiration. state their role in each case
Answers
Answer:
The following are the main factors that affect the rate of transpiration: 1. Sunlight: During daytime, the rate of transpiration is faster. This is because the stomata remain open to allow the inward diffusion ofcarbondioxide for photosynthesis. During dark, the stomata are closed, and hence transpiration hardly occurs at night. 2. Temperature: Transpiration is faster on hot summer days as compared to cold winter. 3. Wind: Transpiration is more when the wind is blowing faster as water evaporates faster from the leaves. 4. Humidity: Transpiration is reduced if the air is humid. Air cannot hold any water molecules when it is already laden with moisture (humidity). 5. Low atmospheric pressure: The rate of transpiration increases when the pressure is low.
Answer:
The following are the factors that affects the rate of transpiration :
1. Sunlight :
Plants transpire more rapidly in the light than in the dark. This is largely because light stimulates the opening of the stomata (a mechanism). Light also speeds up transpiration by warming the leaf.
2. Temperature :
Plants transpire more rapidly at higher temperatures because water evaporates more rapidly as the temperature rises. At 30°C, a leaf may transpire three times as fast as it does at 20°C.
3. Humidity :
The rate of diffusion of any substance increases as the difference in concentration of the substances in the two regions increases. When the surrounding air is dry, diffusion of water out of the leaf goes on more rapidly.
4. Wind :
When there is no breeze, the air surrounding a leaf becomes increasingly humid thus reducing the rate of transpiration. When a breeze is present, the humid air is carried away and replaced by drier air.
5. Soil water :
A plant cannot continue to transpire rapidly if its water loss is not made up by replacement from the soil. When absorption of water by the roots fails to keep up with the rate of transpiration, loss of turgor occurs, and the stomata close. This immediately reduces the rate of transpiration. If the loss of turgor extends to the rest of the leaf and stem, the plant wilts.