`Psi_(w)`inside plant cells is

Options

A. Negative
B. Zero
C. 100
D. Positive

Answer

To determine the value of water potential (Ψ_w) inside plant cells, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Water Potential (Ψ_w):**
- Water potential (Ψ_w) is a measure of the free energy of water in a system. It indicates the potential of water to move from one area to another, particularly in relation to solute concentration and pressure.

2. **Components of Water Potential:**
- Water potential is calculated using the formula:
\[ Ψ_w = Ψ_s + Ψ_p \]
- Where:
- Ψ_w = Water potential
- Ψ_s = Solute potential (also known as osmotic potential)
- Ψ_p = Pressure potential

3. **Identify the Nature of Solute Potential (Ψ_s):**
- In plant cells, the solute potential (Ψ_s) is typically negative due to the presence of solutes (like salts and sugars) in the cell sap. This negative value indicates that the water potential is lower than that of pure water (which has a Ψ_w of 0).

4. **Determine the Pressure Potential (Ψ_p):**
- The pressure potential (Ψ_p) can be positive or zero in plant cells. In turgid (swollen) plant cells, Ψ_p is positive due to the pressure exerted by the cell wall against the cell contents.

5. **Calculate Water Potential (Ψ_w):**
- Since Ψ_s is negative and Ψ_p is positive (or zero), the overall water potential (Ψ_w) inside a plant cell will also be negative. This is because the negative solute potential will outweigh the positive pressure potential.

6. **Conclusion:**
- Therefore, we can conclude that the water potential (Ψ_w) inside plant cells is negative.

### Final Answer:
The value of Ψ_w inside plant cells is negative.

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