turgor

A turgid plant cell (left) and a flaccid plant cell. Water leaves and enters the cell by osmosis. If too much water leaves the cell, for example during drought or saline conditions, then turgor is lost and the cell becomes flaccid. As turgor gives the plant rigidity, loss of turgidity results in the plant wilting.

Rigid condition of a plant caused by the fluid contents of a plant cell exerting a mechanical pressure against the cell wall. Turgor supports plants that do not have woody stems. Plants lacking in turgor visibly wilt. The process of osmosis plays an important part in maintaining the turgidity of plant cells.

When water moves into plant cells by osmosis it makes the cell expand. However, the cell walls are very strong and cannot expand much. So the pressure rises inside the cell – it becomes tightly filled, like a balloon. This makes the cells rigid and this helps to support parts of plants like leaves. Plant cells that are rigid like this are said to be turgid.

If a plant loses too much water, or runs short of water in the soil, it will wilt (leaves and stems droop). If this continues parts of the plant will die because of water loss.