The main difference between turgor pressure and wall pressure is that turgor pressure acts on the cell wall, whereas wall pressure acts on the cell membrane.
Turgor pressure and wall pressure are two pressures that occur in the cell due to endosmosis. Endosmosis is the osmosis towards the cell.
Key Areas Covered
1. What is Turgor Pressure
– Definition, Features, Importance
2. What is Wall Pressure
– Definition, Features, Importance
3. Similarities Between Turgor Pressure and Wall Pressure
– Outline of Common Features
4. Difference Between Turgor Pressure and Wall Pressure
– Comparison of Key Differences
Key Terms
Turgor Pressure, Wall Pressure
What is Turgor Pressure
Turgor pressure is the pressure exerted by a fluid, such as water, against the cell wall. It is also called hydrostatic pressure. Generally, turgor pressure occurs due to the osmotic flow of water. It also occurs in plants, fungi, and bacteria. Without a cell wall, cells undergo lysis under too much pressure. Also, turgidity occurs due to the osmotic flow of water into the cell. Significantly, osmotic flow occurs through a semipermeable membrane. It occurs from a low solute concentration to a high solute concentration. The process of moving water from low to high solute concentration through a semipermeable membrane is called osmosis. Osmosis occurs until the two solute concentrations become equal.
Figure 1: Stomata Opening
Furthermore, the cells are surrounded by a lipid bilayer, which allows the movement of water in and out of the cell through transmembrane proteins called aquaporins. Cells need to be in a hypotonic solution to generate a turgor pressure. Then, the solute concentration outside of the cell is low in comparison to the inside of the cell. Also, it allows the movement of water from outside to inside, increasing the osmotic pressure inside the cell. Sequentially, cells become turgid, and the cell’s content exerts a pressure against the cell wall called the turgor pressure.
Moreover, turgor pressure is important in different processes in plants. It is important for dispersing seeds, opening the stomata, and as the driving force of cell growth.
What is Wall Pressure
Wall pressure is the pressure generated by the cell wall against the cell’s content. It is the opposite pressure of the turgor pressure. Importantly, it occurs in plants, fungi, and bacterial cells containing a cell wall. The cells that do not contain a cell wall, such as animal cells, do not exert wall pressure. Therefore, they undergo cell lysis at the end of the generation of turgor pressure. However, cells with a cell wall do not undergo cell lysis as the cell wall generates an equal but opposite pressure against the cell content by the cell wall. Hence, the key feature of wall pressure is to avoid cell lysis.
Figure 2: Turgor Pressure
Similarities Between Turgor Pressure and Wall Pressure
- Turgor pressure and wall pressure are two pressures exerted by endosmosis.
- They are equal to each other.
- They occur in plant cells, fungi, and bacterial cells.
Difference Between Turgor Pressure and Wall Pressure
Definition
Turgor pressure refers to the pressure that is exerted by the fluid (e.g., water) against the cell wall. In contrast, wall pressure refers to the pressure exerted by the cell wall.
Correspondence
Turgor pressure is applied by the cell’s content against the cell wall, while wall pressure is applied by the cell wall on the cell’s content.
Type of Pressure
Turgor pressure is hydrostatic pressure, while wall pressure is the opposite of turgor pressure.
Importance
Turgor pressure is important for the growth and enlargement of the cell wall, while wall pressure keeps the plants erect.
Conclusion
In brief, turgor and wall pressure are two pressures endosmosis exerts. The content of the cell exerts turgor pressure as a result of endosmosis. It is a hydrostatic pressure. Also, it is important for the growth and enlargement of the cell wall. In comparison, wall pressure is applied by the cell wall on the cell’s content. However, it is the opposite of the turgor pressure. But it is important to keep the plant erect. Therefore, their importance is the main difference between turgor pressure and wall pressure.
References:
- Wikimedia Foundation. (2023ac, August 23). Turgor pressure. Wikipedia. https://en.wikipedia.org/wiki/Turgor_pressure
Image Courtesy:
- “Stoma Opening Closing” By Lmackay2013 – Own work (CC-BY SA 3.0) via Commons Wikimedia
- “Turgor pressure on plant cells diagram ” By LadyofHats – Own Work (Public Domain) via Commons Wikimedia
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