Guard Cells & Stomata
Biology: Edexcel IGCSE, topic 3.2.1
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.