HORTICULTURE

Detailed explanation-1: -Guard cells open and close stomata by expanding and contracting, which causes pore size to change. Osmosis, which depends on the potassium concentration in the cells, rushes water into the guard cells for stomata opening. Potassium must be actively transferred to the vacuoles for the stomata to open.

Detailed explanation-2: -When stomata are open, however, water vapor is lost to the external environment, increasing the rate of transpiration. Therefore, plants must maintain a balance between gas exchange and water loss. Water stress, high temperatures, and high carbon dioxide concentration causes stomata to close.

Detailed explanation-3: -The pore is opened by an increase in osmotic pressure in the guard cells, resulting in the uptake of water. The subsequent increase in cell volume inflates the guard cell and culminates with the opening of the pore.