AP BIOLOGY

Detailed explanation-1: -The turgor pressure of guard cells is controlled by movements of large quantities of ions and sugars into and out of the guard cells. When guard cells take up these solutes, the water potential inside the cells decreases, causing osmotic water flow into the guard cells.

Detailed explanation-2: -Each stoma is surrounded by a pair of sausage-shaped guard cells. In bright light the guard cells take in water by osmosis and become plump and turgid . In low light the guard cells lose water and become flaccid, causing the stomata to close.

Detailed explanation-3: -Excess loss of water through the stoma, such as during a drought, triggers chemical reactions that signal water and ions to leave the guard cells. As solutes exit the guard cells, the pair “deflates, ” subsequently closing the stoma like two flat balloons.

Detailed explanation-4: -They are triggered by sunlight and regulate the rate of transpiration by opening and closing of stomata by change in turgor pressure. During day time, in the presence of light, the stomatal pore opens by taking in water by the process of osmosis and increases the turgidity of the cell.

Detailed explanation-5: -Guard cells are responsible for changing pore size, they do so by expanding or contracting themselves effectively opening and closing stomata. For stomata opening, water is rushed into the guard cells due to osmosis, which is dependent on potassium concentration in the cells.