AP BIOLOGY

Detailed explanation-1: -In many plants, when the outside temperature is warm and water evaporates more readily, plants close their stomata to prevent excessive water loss. Closing the stomata, however, can disrupt plant growth by preventing carbon dioxide from entering the leaves and thereby reducing photosynthesis.

Detailed explanation-2: -But when limited water is available in the soil, plants try to prevent water loss. Water loss through transpiration can be reduced by closing the stomata in the leaves using a substance called ABA. When the stomata is closed photosynthesis will decrease because no CO2 can enter through the closed stomata.

Detailed explanation-3: -Despite the fact that the stomata open in response to light, they may close on a hot day in order to conserve water. This is because the heat may cause the water to evaporate out through the stomata, causing the plant to lose water, reducing the water potential inside the leaf.

Detailed explanation-4: -Stomata open and close as a result of diffusion. Under hot and dry conditions, when water loss due to evaporation is high, stomata must close to prevent dehydration.

Detailed explanation-5: -When temperature increases, the viscosity of water declines and mesophyll conductance (gm) increases, which may improve the supply of water to sites of evaporation and thus increase stomatal aperture (Cochard et al., 2000; von Caemmerer and Evans, 2015).