How does the opening and closing of stomata take place?

The opening and closing of stomata depend on the movement of guard cells: Opening of Stomata – When guard cells absorb water, they become turgid (swollen). This causes them to bend outward, creating an opening (stomatal pore) for exchange of gases and transpiration. Closing of Stomata – When guard cells lose water, they become flaccid (shrunken). As a result, the stomatal pore closes, preventing water loss. Thus, stomata open and close due to changes in the water content of guard cells, controlled by osmotic pressure.