If the rate of transpiration increases, the rate of absorption of water by the root increases too. Factors that affect the rate of transpiration also affect water uptake by the plant. If water is scarce, or the roots are damaged, a plant may wilt.
The rate of transpiration is affected by several factors, including:
This table shows the effects on the rate of transpiration when certain factors are increased.
|Temperature||Increased||Evaporation and diffusion are faster at higher temperatures|
|Humidity||Decreased||Diffusion of water vapour out of the leaf slows down if the leaf is already surrounded by moist air|
|Wind speed||Increased||Moving air removes water vapour, increasing the rate of diffusion of water vapour from the leaf|
|Light intensity||Increased||The stomata open wider to allow more carbon dioxide into the leaf for photosynthesis|