[Photosynthesis] 6.How will stomata closure affect photosynthesis?

Plants can regulate the movements of water vapor, O2 and CO2 through the leaf surface. This is accomplished by opening and closing pores, called stomata, usually found on the bottom side of the leaf. Opening and closing of stomata is controlled by specialized cells called guard cells.

The figure below shows a section of the bottom of a typical leaf as seen through a microscope. The stomate exists as the small opening between the pairs of guard cells.

Guard cells can respond to a variety of environmental and physiological stimuli by opening and closing the stomate. For example, under hot, dry conditions stomata of many plants close to help conserve water. Stomata of most plants also close in the dark.

CO2 used during photosynthesis first must pass through stomata into internal spaces within the leaf. It then diffuses into mesophyll cells where it becomes available for photosynthesis.

When the stomata close, CO2 levels drop rapidly within the leaf, inhibiting the light-independent reactions. This then causes photosynthesis to stop.

Stomata closure limit the intake of carbon dioxide which is important for photosynthesis to take place.This factor is more significant in the day where there is sunlight.