External Factors:-
i) Relative Humidity:- Relative humidity is the percentage of water vapours in the air at a given time and temperature. Transpiration is inversely proportional to the relative humidity in the air. If there is more moisture in the air the less amount of water will evaporates from the plant surface.
i) Relative Humidity:- Relative humidity is the percentage of water vapours in the air at a given time and temperature. Transpiration is inversely proportional to the relative humidity in the air. If there is more moisture in the air the less amount of water will evaporates from the plant surface.
ii) Temperature:- The rate of transpiration is directly proportional to the atmospheric temperature. If there is increase in the temperature in the atmosphere the humidity will decrease and transpiration will increase. High temperature opens stomata even in darkness hence increases the transpiration.
iii) Light:- Stomata opens in the presence of light and therefore transpiration will takes place. Light increases the rate of transpiration. In other way light also increases the atmospheric temperature and again enhance the rate of transpiration.
iv) Velocity of the Wind:- The rate of transpiration is directly proportional to the velocity of the wind or in other words the movement of air increases the rate of transpiration. A wind velocity of 40-50 km/hr decreases transpiration by closing the stomata due to mechanical effect, drying and cooling of the transpiring organ
v) Atmospheric pressure:- Low atmospheric pressure enhances the rate of transpiration.
vi) Availability of water:- The rate of transpiration is also influenced by the availability of water in the soil. Fully turgid guard cells only responsible for opening of stomata. Therefore, A decrease in water uptake by the roots causes partial dehydration of the mesophyll cells resulting in closure of stomata.
Internal Factors:-
i) Rate of transpiration is directly affected by the thickness of cuticle covering on leaf surface. more will be the thickness less will be the transpiration.
ii) Rate of transpiration is directly proportional to the surface area of leaf.
iii) Because most of the transpiration takes place through the stomata therefore, the number of stomata also affects the rate of transpiration. As the number of stomata will increase transpiration will also increase.
iv) Presence of hair and latex reduces the rate of transpiration.
iv) Velocity of the Wind:- The rate of transpiration is directly proportional to the velocity of the wind or in other words the movement of air increases the rate of transpiration. A wind velocity of 40-50 km/hr decreases transpiration by closing the stomata due to mechanical effect, drying and cooling of the transpiring organ
v) Atmospheric pressure:- Low atmospheric pressure enhances the rate of transpiration.
vi) Availability of water:- The rate of transpiration is also influenced by the availability of water in the soil. Fully turgid guard cells only responsible for opening of stomata. Therefore, A decrease in water uptake by the roots causes partial dehydration of the mesophyll cells resulting in closure of stomata.
Internal Factors:-
i) Rate of transpiration is directly affected by the thickness of cuticle covering on leaf surface. more will be the thickness less will be the transpiration.
ii) Rate of transpiration is directly proportional to the surface area of leaf.
iii) Because most of the transpiration takes place through the stomata therefore, the number of stomata also affects the rate of transpiration. As the number of stomata will increase transpiration will also increase.
iv) Presence of hair and latex reduces the rate of transpiration.
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