Plant cell vacuoles are interpreted with expanded regions of the endoplasmic reticulum.
In young plant cells some of these regions are observed, forming small vacuoles isolated from each other. But as the cell reaches adulthood, these small vacuoles fuse into a single large central branch with branches reminiscent of their reticular origin. Expansion of the vacuole causes the rest of the cytoplasm to become compressed and restricted to the peripheral portion of the cell.
In addition, the vacuole's function is to regulate the water changes that occur in osmosis.
In freshwater protozoa there are pulsatile vacuoles (also called contractile), which play the role of osmotic regulators. Constant ingress of water from the middle into the cell endangers cellular integrity. Continuous removal of this water keeps cell fluid concentration constant and avoids the risk of cell disruption. It is a work that consumes energy.