turg

Turg, in informal or shorthand usage, refers to turgor pressure in plant cells. The formal term is turgor pressure (also called turgidity), the hydrostatic pressure exerted by the cell contents against the cell wall. The concept arises from water uptake by the cell’s vacuole through osmosis, which pushes the plasma membrane and cytoplasm against the rigid cell wall. In most scientific texts, the term “turg” is not standard, and researchers typically write “turgor” or “turgor pressure.”

Mechanism and role. Turgor pressure results from water inside the cytoplasm and vacuole pressing outward on the cell wall. This pressure provides internal support, helping to keep non-woody tissues rigid and upright. It also drives several growth processes: as cells expand, walls loosen in a controlled way, allowing turgor to push outward and enlarge the cell. In leaves and stems, fluctuations in turgor influence stiffness and posture. In stomatal guard cells, rapid changes in turgor regulate the opening and closing of stomata, affecting gas exchange and water loss.

Measurement and typical values. Turgor is often discussed qualitatively in many contexts, but it can be measured with pressure probes or inferred from osmotic potential and water status. Quantitatively, plant cell turgor pressures commonly fall in the range of about 0.2 to 0.8 megapascals (roughly 2 to 8 bars), varying with tissue type, developmental stage, and environmental conditions.

Related concepts. Turgor is balanced by cell wall tension and is opposed when water is lost, leading to plasmolysis under extreme conditions. It is five to tenable in coordination with osmosis, water potential, and cell wall mechanics.