Water potential is equal to osmotic potential and pressure potential in

Options

A. Turgid cell
B. Flaccid cell
C. Partly turgid cell
D. All the above

Answer

To solve the question "Water potential is equal to osmotic potential and pressure potential in," we need to understand the concepts of water potential, osmotic potential, and pressure potential.

### Step-by-Step Solution:

1. **Understanding Water Potential**:
- Water potential (Ψw) is a measure of the potential energy of water in a system. It determines the direction of water movement and is influenced by solute concentration and pressure.
- Mathematically, it is expressed as:
\[ Ψw = Ψs + Ψp \]
where:
- Ψw = water potential
- Ψs = osmotic potential (also known as solute potential)
- Ψp = pressure potential

2. **Defining Osmotic Potential**:
- Osmotic potential (Ψs) is the potential of water to move across a semipermeable membrane due to solute concentration. The more solute present, the lower the osmotic potential (more negative value).

3. **Defining Pressure Potential**:
- Pressure potential (Ψp) is the physical pressure exerted on the water in a plant cell. In turgid cells, this pressure is positive due to the cell wall pushing against the internal pressure of the cell.

4. **Analyzing the Options**:
- The question asks when water potential is equal to the sum of osmotic potential and pressure potential.
- In turgid cells, the pressure potential is positive, and the osmotic potential is negative, but their sum gives the water potential.
- In plasmolyzed (flaccid) cells, the pressure potential is zero or negative, and thus the relationship still holds.
- Therefore, the equation holds true for turgid cells, flaccid cells, and partly turgid cells.

5. **Conclusion**:
- Since the equation Ψw = Ψs + Ψp is universally applicable to all types of cells, the correct answer to the question is "all of the above."

### Final Answer:
Water potential is equal to osmotic potential and pressure potential in **all of the above** (turgid cells, flaccid cells, partly turgid cells).

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