turgorivoima

Turgorivoima, often simply referred to as turgor, is a vital concept in plant biology that describes the internal pressure exerted by the cell contents against the cell wall. This pressure arises from the osmotic movement of water into the plant cell. When a plant cell is placed in a hypotonic environment, meaning the concentration of solutes outside the cell is lower than inside, water moves by osmosis across the semipermeable plasma membrane into the cell. This influx of water causes the vacuole, a large organelle within plant cells, to expand and push the cytoplasm against the rigid cell wall.

The cell wall, being relatively inelastic, resists this outward pressure, resulting in an inward force that balances the osmotic pressure. This internal pressure, the turgor pressure, is what keeps plant tissues firm and rigid. It plays a crucial role in maintaining the shape and structure of non-woody plant parts like leaves and stems, preventing wilting.

Turgor pressure is also essential for various physiological processes in plants. It drives cell expansion during growth, allowing plants to increase in size. Furthermore, it is involved in the movement of plant parts, such as the opening and closing of stomata, which regulate gas exchange, and the bending of leaves and flowers in response to stimuli. When a plant loses water, the turgor pressure decreases, leading to flaccidity and wilting. Conversely, adequate water uptake replenishes turgor, restoring firmness.