One of the following is always negative for a plant cell

Options

A. Pressure potential
B. Osmotic potential
C. Osmotic pressure
D. 1 and 2

Answer

To solve the question "One of the following is always negative for a plant cell," we need to analyze the options provided and understand the concepts of pressure potential, osmotic potential, and osmotic pressure in plant cells.

### Step-by-Step Solution:

1. **Understanding the Terms:**
- **Pressure Potential (Ψp):** This refers to the physical pressure exerted by the fluid (water) inside the plant cell against the cell wall. It can be positive or zero, depending on the turgor pressure in the cell.
- **Osmotic Potential (Ψs):** This is the potential of water to move into a cell by osmosis. It is always negative in plant cells because it reflects the tendency of water to move from areas of higher water concentration (lower solute concentration) to areas of lower water concentration (higher solute concentration).
- **Osmotic Pressure:** This is the pressure required to prevent water from moving into a solution via osmosis. It is typically positive, as it counteracts the osmotic potential.

2. **Analyzing the Options:**
- **Option 1: Pressure Potential** - This can be positive or zero, depending on the turgor pressure in the cell.
- **Option 2: Osmotic Potential** - This is always negative in plant cells due to the presence of solutes that attract water.
- **Option 3: Osmotic Pressure** - This is generally positive, as it is the pressure needed to stop osmosis.
- **Option 4: One and Two both (Pressure and Osmotic Potential)** - This option suggests both pressure potential and osmotic potential are negative, which is incorrect since pressure potential can be positive.

3. **Conclusion:**
- Based on the definitions and analysis, the only option that is always negative for a plant cell is **Osmotic Potential (Option 2)**.

### Final Answer:
**Osmotic Potential is always negative for a plant cell.**