AP BIOLOGY

Detailed explanation-1: -K+ ions move out of the cell. This causes the stomatal pore to close. This occurs in the absence of light or when rates of photosynthesis are low.

Detailed explanation-2: -To put it simply, potassium regulates the opening and closing of plant stomata. Stomates are the pores on plant leaves that allow for gas and water vapor exchange. When plants have adequate potassium, the guard cells swell and allow for complete closure of the stoma opening.

Detailed explanation-3: -According to the potassium pump theory, the movement of potassium ions across the cell membranes of the guard cells of the stomata leads to changes in the osmotic pressure of the surrounding cells. This, in turn, changes the turgor pressure of the guard cells causing the closing and opening of the stomata.

Detailed explanation-4: -Potassium ions movement into and out of guard cells is related to the turgidity and consequent opening and closing of stomatal pore.

Detailed explanation-5: -Plants with high amounts of potassium were found to have the lowest transpiration rates. Shoot/root ratio, stomatal frequency, and stomatal aperture were correlated with the potassium concentration in the leaves.