How do different environmental conditions influence transpiration?

Environmental conditions such as light intensity, temperature, humidity, and wind speed significantly influence the rate of transpiration in plants.

Light intensity is one of the primary factors affecting transpiration. In bright light, the stomata (tiny openings on the leaf surface) open wider to allow more carbon dioxide to enter for photosynthesis. This, in turn, increases the rate of transpiration. Conversely, in low light conditions, the stomata close, reducing transpiration.

Temperature also plays a crucial role. As temperature increases, the rate of evaporation from the leaf surface rises, leading to a higher rate of transpiration. This is because the water holding capacity of air increases with temperature, creating a steeper water potential gradient between the leaf and the surrounding air, thus promoting transpiration.

Humidity, or the amount of water vapour in the air, inversely affects transpiration. In high humidity conditions, the rate of transpiration decreases because the air is already saturated with water vapour, reducing the water potential gradient. On the other hand, in low humidity conditions, the rate of transpiration increases due to a higher water potential gradient.

Wind speed can also influence transpiration. In still air, a layer of saturated air, known as the boundary layer, forms around the leaf, reducing the water potential gradient and thus the rate of transpiration. However, in windy conditions, this boundary layer is blown away, increasing the water potential gradient and consequently the rate of transpiration.

In summary, environmental conditions can significantly influence the rate of transpiration in plants. Understanding these factors is crucial for managing water use in plants, particularly in agriculture and horticulture, where water use efficiency is a key concern.