Transpiration

Key Stage 4

Meaning

This diagram shows water being transported from the roots to the leaves of a plant.

Transpiration is the process by which water is transported from the roots of a plant to the leaves.

About Transpiration

In transpiration water evaporates from the leaves and is then replaced by water that is drawn up through the stem from the roots.

Transpiration is needed to bring a constant supply of water and minerals to the leaf for photosynthesis.

Water is lost from the plant through the stomata, so it is important for the plant to be able to close the stomata to control water loss.

If too much water is lost through transpiration the plant may begin to wilt.

Factors Affecting Transpiration

The rate of transpiration is affected by:

• Temperature - High temperatures lead to quicker evaporation of water increasing the rate of transpiration.
• Humidity - High humidity makes it harder for water to evaporate slowing the rate of transpiration.
• Wind - The constant flow of air causes evaporation to happen more quickly increasing the rate of transpiration.