Correct expression for water potential of plasmolysed cell will be

Options

A. `Psi_(W)=Psi_(S)`
B. `Psi_(S)=Psi_(W)`
C. `Psi-(W)=0`
D. `Psi_(W)=Psi_(S)+(Psi_(P))`

Answer

To determine the correct expression for the water potential of a plasmolyzed cell, we need to understand the components of water potential and how they change during plasmolysis.

### Step-by-Step Solution:

1. **Understanding Water Potential**:
Water potential (Ψw) is the measure of the potential energy of water in a system and is influenced by solute potential (Ψs) and pressure potential (Ψp). The relationship is given by the equation:
\[ Ψw = Ψs + Ψp \]

2. **Plasmolysis Context**:
In a plasmolyzed cell, the cell has lost water due to being placed in a hypertonic solution. This results in the shrinkage of the protoplast away from the cell wall.

3. **Pressure Potential (Ψp)**:
In a plasmolyzed cell, the pressure potential (Ψp) is zero because the cell is no longer turgid. Turgor pressure is the pressure exerted by the fluid inside the cell against the cell wall, and it is absent in plasmolyzed cells.

4. **Solute Potential (Ψs)**:
As the cell loses water, the concentration of solutes increases, making the solute potential (Ψs) more negative. This means that Ψs decreases as the cell plasmolyzes.

5. **Applying the Equation**:
Since Ψp = 0 in a plasmolyzed cell, the equation simplifies to:
\[ Ψw = Ψs + 0 \implies Ψw = Ψs \]

6. **Conclusion**:
Therefore, the correct expression for the water potential of a plasmolyzed cell is:
\[ Ψw = Ψs \]

### Final Answer:
The correct expression for the water potential of a plasmolyzed cell is \( Ψw = Ψs \).

---