Before looking at the factors firstly let’s dive ( know ) what is Transpiration?
Definition of transpiration : Transpiration is the loss of water in the form of water vapor from the plant to the atmosphere under the influence of sunlight. Most water loss is through the stomata of the leaves while little is lost through the cuticle of lenticels of the stem.
Factors that influence Transpiration
- Sunlight : Sunlight produces heat energy which increases the heat in the body of the plant. Under this condition the plant loses water vapor freely. Transpiration increase steadily with increasing light intensity. Plant transpire less in low light intensity.
- Temperature: Transpiration increases with increase in temperature and decrease with decreasing temperature.
- Wind: As wind sweeps always the water vapor around the plant more transpiration takes place. This means that plants will transpire more under a gentle wind and less when there is no wind at all. Wind of very high speed cause the stomata to close up and stomata transpiration stops.
- Humidity: This is the presence of water vapor in the atmosphere. At high humidity when the surrounding air has much water vapor the plants transpire less. At low humidity when the surrounding air has less water vapor the plants transpire profusely.
- Availability of water: Transpiration will go on steadily if there is water in the soil for the plant to absorb and replenish the one that is being lost. Transpiration will stop if there is no water supply to the plant to replace the one that is being lost.
- Stomata: The number, size and distribution of stomata determine the rate of transpiration. Leaves with large stomata will transpire more than those with small ones.Monocotyledons plants such as maize grasses with stomata on both sides of their leaves transpire more than dicotyledons plants such as okra, groundnut with stomata on the under sides of their leaves.
- Guttation: This is the removal of excess water in form of liquid at night through special pores on the leaf margin. These water pores are known as hydathodes.