A guard cell is one of the specialized epidermal biological cells bordering a stoma. Changes in solute content alter water uptake and turgor pressure, changing the size of the pore. This couples transpiration and entry of carbon dioxide for photosynthesis.
Calcium-dependent signaling and regulation of anion channels participate in closing responses. Experiments imposing different calcium patterns tested how intracellular dynamics influence stomatal movement, showing why a single concentration measurement may miss information carried by its timing.[ref]
New to topics? Read the docs here!