Factors affecting transpiration

The rate of transpiration is affected by several factors. These include:

The table below explains how factors increase the rate of transpiration:

Factor	Change in factor that increases transpiration rate	Explanation
Temperature	Increases	An increase in temperature increases evaporation, so the rate of diffusion of water from inside the leaf to outside increases
Humidity	Decreases	A decrease in humidity reduces the concentration of water molecules outside the leaf, so the rate of diffusion of water from inside the leaf to outside increases
Air movement	Increases	An increase in air movement removes water vapour from outside the leaf, so the rate of diffusion of water from inside the leaf to outside increases
Light intensity	Increases	An increase in light intensity generally increases the number of open stomata, so the rate of diffusion of water from inside the leaf to outside increases

Factor	Temperature
Change in factor that increases transpiration rate	Increases
Explanation	An increase in temperature increases evaporation, so the rate of diffusion of water from inside the leaf to outside increases

Factor	Humidity
Change in factor that increases transpiration rate	Decreases
Explanation	A decrease in humidity reduces the concentration of water molecules outside the leaf, so the rate of diffusion of water from inside the leaf to outside increases

Factor	Air movement
Change in factor that increases transpiration rate	Increases
Explanation	An increase in air movement removes water vapour from outside the leaf, so the rate of diffusion of water from inside the leaf to outside increases

Factor	Light intensity
Change in factor that increases transpiration rate	Increases
Explanation	An increase in light intensity generally increases the number of open stomata, so the rate of diffusion of water from inside the leaf to outside increases

Plants living in different habitats have adaptations to resist extremes of these factors.

Question

What conditions will decrease the rate of transpiration?