Turgor pressure

As turgor ( turgor pressure also ) is referred to in Plant Physiology and Cell Biology at the pressure of the cell sap on the cell wall. If the osmotic value in the cell is higher than in the surrounding apoplast, takes them through deplasmolysis on water. The rising pressure in its interior spans the surrounding cell wall. Of turgor is not bolstered by the elastic wall pressure that counteracts it. If the turgor its largest possible value, then one speaks of full turgidity. However, if the osmotic value of the surrounding medium is greater than in the cell sap ( hypertonic medium ), the turgor pressure decreases and the protoplast is released from the cell wall ( plasmolysis → ). On the interplay of turgor and wall pressure, the strength is based herbaceous, nichtverholzter plants.

Turgor and water potential

The osmotic value contributes to the negative osmotic pressure ( as " osmotic potential " ) to the water potential. The difference of water potential between the cell and its environment determines whether the cell absorbs or releases water. Water moves in the direction of more negative potential; while pure water has the highest possible value, namely increase 0 Dissolved and colloidal substances present the osmotic value of the cell sap and reduce the water potential of the cell. If this is lower than the water potential of the surrounding environment, water flows through the plasma membrane and tonoplast in the protoplasts and thus increases the turgor. At full turgidity the water potential of the cell or the tissue has reached the value 0, in which no more water may be added. This condition is rarely achieved because of transpiration in the plant water potential decreased in the apoplast.

The turgor pressure in plant cells is 0.07 up to 4 megapascals.

Effects of turgor

Glandular tissue can secrete the help of turgor secretions. Due to changes of the turgor of the closing or secondary cells, the plant may control the opening condition of the stomata ( stomata ). The effects caused by vibrations leaf movements ( Nastien ) of mimosa are also based on local turgor. Some plants (juice pressure spreader ) disperse their seeds by means of Turgorschleuder ( Spring herbs) or Turgorspritzmechanismen. Pressures up to 1.5 megapascals ( 15 bar ) and ranges up to 12 meters ( squirting cucumber ) can be achieved.