Root hairs cells under ordinary conditions typically have water potential in the range of

Options

A. 1 to 4 atmospheres
B. -1 to -4 atmospheres
C. 1 to 2 atmospheres
D. -1 to 2 atmospheres

Answer

To determine the typical water potential range of root hair cells under ordinary conditions, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Water Potential**: Water potential (Ψ) is a measure of the potential energy in water and is influenced by the concentration of solutes. Pure water has a water potential of zero.

2. **Effect of Solutes**: When solutes (like minerals) are added to water, the number of free water molecules decreases, which lowers the water potential. Therefore, the presence of solutes in root hair cells will result in a negative water potential.

3. **Typical Conditions in Root Hair Cells**: Root hair cells absorb water and minerals from the soil. Since the soil contains various solutes (minerals), the water potential in these cells will be lower than that of pure water.

4. **Range of Water Potential**: For root hair cells, the water potential typically ranges from negative values. The expected range is between -1 to -4 atmospheres. This is because the presence of solutes (minerals) in the soil decreases the water potential further below zero.

5. **Evaluating the Options**:
- **Option A (1 to 4 atmospheres)**: This is positive and therefore incorrect.
- **Option B (-1 to -4 atmospheres)**: This is negative and fits our findings, making it a potential correct answer.
- **Option C (1 to 2 atmospheres)**: This is also positive and incorrect.
- **Option D (-1 to 2 atmospheres)**: This includes a positive value, making it incorrect.

6. **Conclusion**: The correct answer is **Option B (-1 to -4 atmospheres)**, as it accurately reflects the typical water potential range of root hair cells under ordinary conditions.