Describe mechanisms of opening and closing of stomata

Answer:

- Guard cells have chloroplasts unlike other epidermal cells.
-During daylight, they carry out photosynthesis producing glucose. The glucose increase the osmotic pressure of the cell sap. This causes water to move into guard cells from the neighbouring epidermal cells by osmosis.
-The results is an expansion and increase in turgidity
of the guard cells causing the stomata to open.
-In darkness, photosynthesis stop. The glucose in the guard cells is converted to starch. Starch is osmotically inactive. This lowers the osmotic pressure of the guard cells causing them to lose water to neighbouring epidermal cells by osmosis. The guard cells become flaccid and the stomata close

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