How is Gas exchanged in plants?
The stomata, found in the lower epidermis, controls the gas exchange. carbon dioxide diffuses into the cell and oxygen and water vapour diffuses out of the cell. The opening and closing of the stomata is controlled by guard cells.When the plant has lots of water the guard cells go turgid and makes the stomata open so gases are exchanged. When the plant has little water, the guard cells become flaccid and close the stomata. This minimises the amount of water vapour escaping.