What is Transpiration?

Transpiration is the process by which water is absorbed by plant roots and then released into the atmosphere through small openings on the leaves called stomata. It is driven by the combination of factors such as diffusion, root pressure, and capillary action.

Factors Affecting Transpiration

• Temperature: Higher temperatures increase transpiration rates as they cause the stomata to open wider, allowing for more water to evaporate.
• Humidity: Lower humidity levels result in an increased rate of transpiration, as the concentration gradient between the leaf and the surrounding air is steeper.
• Wind: Increased air movement can carry away water vapor from the leaf surface, increasing the rate of transpiration.
• Light: Intense light stimulates the opening of stomata, leading to higher transpiration rates.

Importance of Transpiration

Transpiration serves several important functions in plants, including:

• Water transport: It helps in the movement of water and nutrients from the roots to the rest of the plant.
• Cooling effect: The evaporation of water from the leaves helps to cool the plant, especially in hot conditions.
• Gas exchange: Transpiration facilitates the exchange of gases, such as oxygen and carbon dioxide, between the plant and the atmosphere.

Transpiration and the Water Cycle

Transpiration is a significant component of the water cycle, as it contributes to the movement of water from the soil to the atmosphere. The water vapor released during transpiration eventually condenses to form clouds and may return to the Earth's surface as precipitation.

Experimental Study of Transpiration

Students can conduct experiments to study transpiration, such as the use of a potometer to measure the rate of water uptake by a plant, or the use of cobalt chloride paper to demonstrate the change in color due to transpiration.