Which of the following has negligible contribution to water potential in a fully flaccid cell

Options

A. `Psi`
B. `Psipi`
C. `Psi_(p)`
D. None of the above

Answer

To solve the question "Which of the following has negligible contribution to water potential in a fully flaccid cell?", we need to understand the components of water potential and how they behave in a flaccid cell.

### Step-by-Step Solution:

1. **Understand Water Potential**:
Water potential (Ψ) is the potential energy of water in a system compared to pure water, and it is influenced by two main components:
- **Solute Potential (Ψs)**: This is the effect of solute concentration on water potential.
- **Pressure Potential (Ψp)**: This is the physical pressure on the water in the cell.

2. **Identify the State of a Fully Flaccid Cell**:
A fully flaccid cell is one that has lost a significant amount of water, leading to a decrease in turgor pressure. In this state, the cell is not exerting pressure against its cell wall.

3. **Analyze Pressure Potential (Ψp)**:
In a fully flaccid cell, the pressure potential (Ψp) becomes zero because there is no pressure exerted by the cell contents against the cell wall. This means that Ψp has a negligible contribution to the overall water potential.

4. **Evaluate the Other Components**:
- **Solute Potential (Ψs)**: This component still exists as long as there are solutes present in the cell, and it contributes to the overall water potential.
- **Water Potential (Ψ)**: The overall water potential in a fully flaccid cell can be expressed as Ψ = Ψs + Ψp. Since Ψp is zero, Ψ = Ψs.

5. **Conclusion**:
Since the pressure potential (Ψp) is zero in a fully flaccid cell, it has negligible contribution to the water potential. Therefore, the correct answer is option 3: Ψp.

### Final Answer:
The component that has negligible contribution to water potential in a fully flaccid cell is **Ψp (Pressure Potential)**.

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