In a plant cell DPD is zero when it is

Options

A. Plasmolysed
B. Turgid
C. Flaccid
D. Incipient

Answer

### Step-by-Step Solution:

1. **Understanding DPD**:
- DPD stands for Diffusion Pressure Deficit. It is defined as the difference in pressure between pure water and a solution. Mathematically, it can be expressed as:
\[ \text{DPD} = \text{Osmotic Pressure} - \text{Turgor Pressure} \]

2. **Defining Osmotic Pressure and Turgor Pressure**:
- **Osmotic Pressure**: This is the pressure required to stop the flow of water into a solution when separated by a semipermeable membrane.
- **Turgor Pressure**: This is the pressure exerted by the fluid (typically water) inside the cell against the cell wall.

3. **Analyzing Conditions of Plant Cells**:
- When a plant cell is placed in a **hypotonic solution**, it absorbs water through the process of **endosmosis**. This causes the cell to swell and become turgid.
- In a turgid state, the cell membrane is fully stretched, and the osmotic pressure equals the turgor pressure.

4. **Determining DPD in Different States**:
- **Turgid**: In this state, osmotic pressure equals turgor pressure, resulting in DPD being zero.
- **Plasmolyzed**: When a cell is plasmolyzed, it has lost water and shrinks away from the cell wall, leading to a positive DPD.
- **Flaccid**: In a flaccid state, the cell is not turgid, and there is a difference between osmotic pressure and turgor pressure, resulting in a positive DPD.
- **Incipient Plasmolysis**: This is the stage just before plasmolysis occurs, where the cell is still losing water, resulting in a positive DPD.

5. **Conclusion**:
- Therefore, the correct answer to the question "In a plant cell, DPD is zero when it is..." is **turgid**.