A single large tree can lose hundreds of litres of water a day as vapour. Explore how and why plants transpire.
Transpiration is the loss of water vapour from a plant's surface, mostly through tiny pores called stomata, usually found on the underside of leaves.
Through which structures does most transpiration occur?
Stomata, tiny pores mostly found on the underside of leaves
Guard cells control the opening and closing of each stoma. As water evaporates from leaf cells and escapes through open stomata, it creates a pulling force (transpiration pull) that helps draw water up from the roots through the stem.
What is the 'transpiration pull'?
The pulling force created as water evaporates and leaves through stomata, which helps draw more water up through the plant from the roots
1. What is transpiration?
2. Through which structures does most water vapour escape a leaf?
3. What controls the opening and closing of a stoma?
4. On which side of a leaf are stomata usually more numerous?
5. What is the transpiration pull?
6. Why might a plant close its stomata during a very hot, dry day?
7. Name one factor that can increase the rate of transpiration.
8. Is transpiration useful to a plant, or just unavoidable water loss?
9. What gas also enters/exits through stomata, besides water vapour?
10. Why do desert plants often have fewer or smaller stomata than plants in wet climates?