Potassium is ___ transported into and out of the vacuoles in the guard cells.

Potassium is actively transported into and out of the vacuoles in the guard cells.

There are different kind of potassium transport channels (KAT1, KAT2) that transport K + inside and outside the vacuole of the guard cell, by the use of ATP (energy) and H+.

Potassium is actively transported into and out of the vacuoles in the guard cells. The sodium-potassium pump is responsible for the process of moving sodium and potassium ions across the cell membrane which is an active transport process involving the hydrolysis of ATP to provide necessary energy required. Accumulation of potassium ions in the guard cells causes turgidity which keeps the stomata open.