Turgor

Turgor is the pressure exerted by the contents of a plant cell against its cell wall. It arises when water fills the central vacuole and osmosis drives water into the cell, increasing hydrostatic pressure until the wall resists further expansion. The resulting turgor pressure helps keep the cell rigid and contributes to the mechanical support of non-woody tissues.

Turgor is essential for plant growth and form. It provides mechanical support, enables cell expansion during growth, and in guard cells drives stomatal opening when they inflate. Water loss lowers turgor and causes wilting; severe water loss can lead to plasmolysis, in which the plasma membrane pulls away from the cell wall.

Turgor interacts with the plant’s overall water potential. It depends on osmotic potential and the elasticity of the cell wall, and is typically described as a component of hydration-related pressure that changes with hydration status. While most prominent in plants, turgor-like pressure also exists in fungi and some bacteria to help maintain cell shape, though growth and physiology differ among these organisms.