turgor

Turgor pressure pushes the plasma membrane against the cell wall of plant, bacteria, and fungi cells as well as those protist cells which have cell walls. This pressure, turgidity, is caused by the osmotic flow of water from area of low solute concentration outside of the cell into the vacuole, which has a higher solute concentration.

Healthy plant cells are turgid and plants rely on turgidity to maintain rigidity. In contrast, this phenomenon is not observed in animal cells which have no cell walls to prevent them from being burst by the flow of water into the cell and must either continually pump out water or live in an isotonic solution where there is no osmotic pressure.