A living cell is a holistic biosystem, all parts of which must work in conjunction to ensure normal functioning and life in general. One of the characteristics that directly affects the viability of a particular plant cell is turgor pressure. There are quite serious structural differences between plant and animal cells. This is due to the belonging of their organisms to different kingdoms with different needs and life cycles.
Turgor pressure
This is primarily the ability of the cell not to lose shape due to the pressure of the fluid from the inside onto the cell wall. Thanks to a process called osmosis in physics, a liquid enters a dried cell through the membrane, which occupies a certain volume, as if pushing the cell cytoplasm closer to its outer membrane. Such fluid pressure is also necessary in order to regulate the process of further fluid intake: when the cell is completely filled, osmosis stops.
It should be separately clarified that animal cells, due to the lack of vacuoles and cell juice in them, have minimal turgor pressure. Therefore, further information will only concern plant cells - the turgor in them is very significant.
Osmotic pressure
Osmotic and turgor pressure should not be confused, despite the fact that the processes are similar in description. In fact, osmotic pressure is an integral part of turgor: external and internal osmosis, combined with the level of elasticity of the cell wall, ensure that the balance of the internal pressure of the fluid in the cell is maintained. Thus, upon reaching the fluid threshold in the cell, the internal osmotic pressure begins to impede the flow of a new solution. And if the level of internal osmotic pressure drops, then with the help of an external fluid again begins to flow into the cell.
Organoids
What organoids are involved in creating turgor pressure? All parts of the cell are combined into a single system. Therefore, one way or another, everyone is involved in supporting turgor pressure. However, the vacuole, without a doubt, has the greatest influence on the creation of turgor pressure and its maintenance. It contains the reserves of cellular juice, which is necessary, among other things, to maintain turgor.
The next most important organoid for turgor pressure after vacuole is the cell wall. It is semi-permeable and allows only strictly defined substances dissolved in liquids to pass through, delaying unwanted ones. Also, its elasticity directly affects the preservation of the cell shape. In the event that the cell wall is damaged, with excessive pressure on the cell, the cell may collapse.
Turgor Functions
In addition to the rather obvious function of maintaining the shape of the cell, turgor pressure is also a direct effect on all physiological processes of the cell. It regulates water metabolism, allows you to balance the total pressure in the cell, is involved in the nutrition process. But since the cell is a holistic system, it will not be a mistake to say that this pressure affects literally all the life activity of both a single cell and a whole plant.
Also, some of the organs of the plant (mainly those that provide it with food: roots, rhizomes , etc.) are directly dependent on the regulation of turgor pressure. It determines the ability of the root to absorb nutrients from the environment. And, as a result, provide the plant with life itself. The balance of intracellular pressure allows the plant to receive exactly as many nutrients as it needs. No more and no less.
Plant cell pressure regulation
As noted above, turgor is controlled by the difference between the internal pressure of the liquid and the substances dissolved in it and the external pressure of the medium. With a significant drop in internal pressure, the cell begins to let in liquid and tries to replenish the reserves of cell juice as quickly as possible.
But there is one caveat. If the amount of liquid substance inside has become significant, and it began to exert increased pressure on the outer wall of the cell, then the supply of new reserves temporarily ceases and resumes only when the internal pressure drops again. Thus, the content in the cell of both the liquid itself and the substances dissolved in it is regulated.
However, in addition to the pressure balance, the cell membrane can also influence turgor. How? A change in its permeability and elasticity can change both the filling of the cell juice with certain substances, and the level of pressure that the cell can withstand.
The fact that without turgor plants would be incapable of existence is obvious. Such a simple, but at the same time important process, such as the intake and consumption of fluid in the cell, affects the whole life of a living organism and requires control, for which purpose specialized organoids, such as vacuoles, were created.