If by radiation all nitrogenase enzymes are inactivated, then there will be no

Options

A. fixation of atmospheric nitrogen
B. conversion from nitrate to nitrite in legumes
C. conversion from ammonium to nitrate in soil
D. fixation of nitrogen in legumes

Answer

To solve the question, "If by radiation all nitrogenase enzymes are inactivated, then there will be no," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Role of Nitrogenase**:
- The nitrogenase enzyme is crucial for the biological nitrogen fixation process. It catalyzes the conversion of atmospheric nitrogen (N2) into ammonia (NH3), which is a form that plants can utilize.

2. **Implications of Inactivation**:
- If all nitrogenase enzymes are inactivated due to radiation, the process of converting atmospheric nitrogen into ammonia will cease. This means that nitrogen fixation will not occur.

3. **Evaluate the Options**:
- **Option A**: No fixation of atmospheric nitrogen - This is true since nitrogenase is responsible for this process.
- **Option B**: Conversion from nitrate to nitrite in legumes - This process does not directly involve nitrogenase; it involves other enzymes.
- **Option C**: Conversion from ammonium to nitrite in soil - This is also not directly related to nitrogenase activity.
- **Option D**: Fixation of nitrogen in legumes - This is directly related to the function of nitrogenase.

4. **Conclusion**:
- Since nitrogenase is responsible for the fixation of atmospheric nitrogen, if it is inactivated, there will be no fixation of nitrogen in legumes. Therefore, the correct answer is **Option D**.

### Final Answer:
If by radiation all nitrogenase enzymes are inactivated, then there will be no fixation of nitrogen in legumes (Option D).