`Psi_(p)`=0 in

Options

A. Flaccid cell
B. Pure water
C. Turgid cell
D. 1 and 2

Answer

To solve the question regarding when the pressure potential (Ψp) equals zero, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Pressure Potential (Ψp)**:
- Pressure potential (Ψp) is the physical pressure exerted by the fluid inside the cell against the cell wall. It is a component of water potential.

2. **Water Potential Equation**:
- The water potential (Ψw) of a cell can be expressed as:
\[ Ψw = Ψs + Ψp \]
- Where Ψs is the solute potential (the potential due to solute concentration).

3. **Condition for Ψp to be Zero**:
- For Ψp to equal zero, the equation can be rearranged to:
\[ Ψp = Ψw - Ψs \]
- If Ψp is zero, it implies that:
\[ Ψw = Ψs \]

4. **Flaccid Cells**:
- A flaccid cell is one that has lost water and has no turgor pressure. In this state, the cell is not under pressure from water entering it, leading to:
- Ψp = 0 (no pressure potential)
- Ψw = Ψs (the water potential equals the solute potential)

5. **Conclusion**:
- Therefore, the condition under which Ψp equals zero is found in a flaccid cell.

### Final Answer:
Ψp = 0 occurs in a flaccid cell.

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