You are given three cells, a root hair, a cell of the inner cortical layer and a cell of the mesophyll arrange them in ascending order of DPD :

Options

A. Root hair `lt` Cortical cell `lt` Mesophyll
B. Cortical cell `lt` Mesophyll `lt` Root hair
C. Mesophyll `lt`Root hair `lt` Cortical cell
D. Root hair `lt` Mesophyll `lt` Cortical cell

Answer

To solve the problem of arranging the three cells (root hair, inner cortical layer cell, and mesophyll cell) in ascending order of Diffusion Pressure Deficit (DPD), we can follow these steps:

### Step-by-Step Solution:

1. **Understand DPD**:
- DPD is a measure of the tendency of water to move from one area to another. It is influenced by the concentration of solutes in the cell. A lower DPD indicates a higher water potential, meaning water is more likely to enter the cell.

2. **Analyze the Cells**:
- **Root Hair Cell**: This cell is responsible for the absorption of water from the soil. It typically has a low concentration of solutes, resulting in a low DPD.
- **Inner Cortical Layer Cell**: This cell is located just inside the root and acts as a pathway for water movement towards the vascular tissues. It has a slightly higher concentration of solutes compared to root hair cells, leading to a moderate DPD.
- **Mesophyll Cell**: These cells are found in the leaves and are involved in photosynthesis. They generally have a higher concentration of solutes due to the presence of sugars and other metabolites, resulting in a high DPD.

3. **Order the Cells by DPD**:
- Since the root hair cell has the lowest DPD, followed by the inner cortical layer cell, and finally the mesophyll cell with the highest DPD, we can arrange them in ascending order as follows:
- **Root Hair Cell** (lowest DPD)
- **Inner Cortical Layer Cell** (moderate DPD)
- **Mesophyll Cell** (highest DPD)

4. **Final Arrangement**:
- The ascending order of DPD is:
- Root Hair Cell < Inner Cortical Layer Cell < Mesophyll Cell

### Conclusion:
The correct ascending order of DPD for the three cells is:
- **Root Hair Cell < Inner Cortical Layer Cell < Mesophyll Cell**