The Rate Of Transpiration Flashcards
(5 cards)
State the 4 main factors that affect the rate of transpiration.
Light intensity, temperature, air flow, humidity
How does light intensity affect the transpiration rate?
The brighter the light, the greater the transpiration rate. Stomata begin to close as it gets darker. Photosynthesis can’t happen in the dark, so the stomata doesn’t need to be open to let CO2 in. When the stomata are closed, very little water can escape
How does temperature affect the transpiration rate?
The warmer it is, the faster transpiration happens. When it’s warm, the water particles have more energy to evaporate and diffuse out of the stomata.
How does air flow affect the transpiration rate?
The better the air flow around a leaf (e.g. strong wind), the greater the transpiration rate. If air flow around a leaf is poor, the water vapour just surrounds the leaf and doesn’t move away. This means there is a high concentration f water particles outside the leaf as well as inside it, so diffusion doesn’t happen as quickly. If there is a good air flow, the water vapour is swept away, maintaining a low concentration of water in the air outside the leaf.
How does humidity affect the transpiration rate?
The drier the air around a leaf, the faster transpiration happens. If the air is humid. There is a lot of water in it already, so there is not much of a difference between the inside and the outside of the leaf.
