MP Board · Class 9 · Science · TissuesWhat are guard cells? Explain their role in controlling stomatal movements.

Guard cells are specialized, kidney-shaped epidermal cells that surround each stomatal pore on plant leaves. They contain chloroplasts and have differentially thickened cell walls. Guard cells control the opening and closing of stomata by undergoing turgor changes; when water flows into guard cells, they swell and curve outward to open the pore, and when water leaves, they become flaccid and close it.