Turgornyomás

Turgornyomás, in Hungarian biology, refers to the hydrostatic pressure inside plant cells that results from water uptake and is exerted against the cell wall. It arises when the vacuole and cytoplasm draw in water by osmosis, generating a pressurized interior that pushes outward on the cell wall. In healthy, non-woody tissues, this pressure gives cells their shape and rigidity.

The pressure is part of the plant’s water potential, written as Ψ = Ψs + Ψp, where Ψp is the turgor pressure. When cells take up water, Ψp becomes positive; when water is scarce, Ψp declines and cells become flaccid. If water loss continues in a hypertonic environment, plasmolysis can occur, in which the cell membrane pulls away from the wall.

Functions of turgornyomás include providing mechanical support for tissues, enabling growth by driving cell expansion when the cell wall is extensible, and facilitating movement in certain tissues. It also plays a key role in stomatal opening and closing, as guard cells regulate their turgor to control gas exchange and water loss.

Measurement and factors: Turgor can be measured with a pressure probe or a pressure chamber. It is influenced by soil moisture, the osmotic potential inside the cell vacuole, temperature, and ionic strength. Drought or salinity tends to reduce turgor, while adequate watering and osmotic adjustment help restore it.

Relevance: Turgornyomás is central to plant water status, growth, and drought responses, affecting crop performance and wilting resistance. Managing water availability and soil conditions helps maintain healthy turgor in many agricultural species.