Transpiration |
Transpiration is the movement of water up the plant and exit from the leaf |
Transpiration is the process of water movement through a plant.
Transpiration is when water diffuses out of the leaf and then evaporates. More water is then sucked up the Xylem, like a straw. This can only occur because water is a polar molecule, the water forms a continuous flow and uses adhesion (when the water sticks to the sides of the Xylem) to travel upwards to the leaves. A number of factors effect transpiration rates, and so this will also effect the rate that water is taken up from the ground. |
Factors That Affect Transpiration Rates:
Light Intensity: The rate of transpiration increases with more light. This is because when chlorophyll detects the sunlight it opens the stomata and when the stomata opens the water exits the leaf by osmosis.
Temperature: High temperatures increase the rate of transpiration because evaporation and diffusion are faster at higher temperatures.
Humidity: This decreases the rate of transpiration because as there is more water outside the plant, the diffusion of water vapour decreases is there is more moisture outside the plant. This is because the concentration gradient is less steep.
Wind Speed: Transpiration increases with more wind because the wind blows any moisture around or on the leaf away allowing more water to be released quickly as there is a steeper concentration gradient.
Light Intensity: The rate of transpiration increases with more light. This is because when chlorophyll detects the sunlight it opens the stomata and when the stomata opens the water exits the leaf by osmosis.
Temperature: High temperatures increase the rate of transpiration because evaporation and diffusion are faster at higher temperatures.
Humidity: This decreases the rate of transpiration because as there is more water outside the plant, the diffusion of water vapour decreases is there is more moisture outside the plant. This is because the concentration gradient is less steep.
Wind Speed: Transpiration increases with more wind because the wind blows any moisture around or on the leaf away allowing more water to be released quickly as there is a steeper concentration gradient.