Stomata
Biology: AQA GCSE Higher, topic 2.5.9
Guard Cells and Stomata
Stomata are gaps in the lower epidermis of leaves that facilitate (make easier) the diffusion of gases, including evaporated water, in and out of the leaf. Guard cells can open and close the stomata:
Opening the stomata
- The guard cells can open the stomata by taking up lots of water, causing them to swell.
Closing the stomata
- To close the stomata, the guard cells lose water and return to a limp state.
Test yourself on Stomata
Why is it useful for a plant to close its stomata when its guard cells lose water and become limp?
What is a disadvantage to a plant of closing its stomata?
What would happen to a stoma if its guard cells did not take up enough water?
How does the behaviour of guard cells differ between opening and closing the stomata?