Difference Between Turgor Pressure and Wall Pressure

The key difference between turgor pressure and wall pressure is that turgor pressure is the hydrostatic pressure developed against the cell wall due to endosmosis, while wall pressure is the pressure exerted by the cell wall against the turgor pressure.

Endosmosis is the entering of water inside the cell. It occurs when the water potential of the cell is low in comparison to the outside solution. Hence, water enters the cell via the cell wall and cell membrane. As a result of the entry of water, cytoplasm swells. When the volume of the cytoplasm increases, pressure develops inside the cell against the cell wall. We call this pressure turgor pressure. However, the cell wall is a rigid structure made from cellulose. Hence, it can withstand turgor pressure. The cell wall also generates pressure against the turgor pressure. We call this pressure wall pressure. Moreover, endosmosis ceases when the turgor pressure and wall pressure is equal.

CONTENTS

1. Overview and Key Difference
2. What is Turgor Pressure 
3. What is Wall Pressure
4. Similarities Between Turgor Pressure and Wall Pressure
5. Side by Side Comparison – Turgor Pressure vs Wall Pressure in Tabular Form
6. Summary

What is Turgor Pressure?

Turgor pressure is the force the cytoplasm exerts towards the cell wall when water enters the cell. It is in fact the hydrostatic pressure. It develops when the cytoplasm increases its volume due to endosmosis. For a plant, turgor pressure is very important. It is responsible for the growth and enlargement of the cells.

Furthermore, turgor pressure keeps the plant stem straight. Turgor pressure also keeps leaves expanded and make the leaves face towards the sunlight to capture maximum sunlight for the photosynthesis. Another importance of turgor pressure in plants is the opening and closure of stomata as turgidity of the guard cells governs the opening and closing of stomata.

What is Wall Pressure?

Wall pressure is the pressure generated by the cell wall against the turgor pressure. Wall pressure acts in the opposite direction of the turgor pressure.

When the cell content expands, it pushes the cell wall and the membrane. However, the cell wall is the rigid and elastic structure; hence, it tries to maintain the shape and the size of the cell. Thus, cell wall exerts a pressure on the cell contents.

What are the Similarities Between Turgor Pressure and Wall Pressure?

• Both turgor pressure and wall pressure are important for plants.
• However, both work in opposite directions.
• That is; turgor pressure pushes the cell wall, while wall pressure acts against the turgor pressure.

What is the Difference Between Turgor Pressure and Wall Pressure?

The key difference between turgor pressure and wall pressure is that turgor pressure is the hydrostatic pressure developed against the cell wall due to endosmosis, while the wall pressure is the pressure exerted by the cell wall against the turgor pressure. Therefore,  turgor pressure acts on the cell wall, while the cell wall generates the wall pressure.

Moreover, a further significant difference between turgor pressure and wall pressure is their function. Turgor pressure keeps plant stems erect, keeps leaves expanded, and help in opening and closing of stomata, etc., while wall pressure maintains the structure of cells and the plant.

Summary – Turgor Pressure vs Wall Pressure

Turgor pressure is the pressure created by the cytoplasm towards the cell wall due to endosmosis. In contrast, wall pressure is the pressure that generates by the cell wall against the turgor pressure. So, this is the key difference between turgor pressure and wall pressure. In summary, both turgor pressure and wall pressure are really important for a plant to grow, develop and survive.

Reference:

1.“Turgor Pressure.” Wikipedia, Wikimedia Foundation, 23 June 2019, Available here.
2. Thoday, D. “Turgor Pressure and Wall Pressure.” OUP Academic, Oxford University Press, 1 Apr. 1952, Available here.