If by radiation all nitrogenase enzyme are inactivated, then there will be no:-

Options

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

Answer

### Step-by-Step Solution:

1. **Understanding Nitrogenase Enzyme**:
- The nitrogenase enzyme is crucial for the process of nitrogen fixation, which converts atmospheric nitrogen (N₂) into ammonia (NH₃). This process is essential for making nitrogen available to plants.

2. **Role of Nitrogen-Fixing Bacteria**:
- Nitrogenase is produced by nitrogen-fixing bacteria, which can exist in the soil or in symbiotic relationships with plants, particularly legumes. An example of such bacteria is Rhizobium, which forms a symbiotic relationship with legumes.

3. **Impact of Inactivation by Radiation**:
- If all nitrogenase enzymes are inactivated due to radiation, the process of nitrogen fixation cannot occur. This means that atmospheric nitrogen cannot be converted into a usable form (ammonia) for plants.

4. **Conclusion**:
- Therefore, if nitrogenase enzymes are inactive, there will be no fixation of nitrogen in legumes, leading to a deficiency of nitrogen in the soil and affecting plant growth.

5. **Final Answer**:
- If by radiation all nitrogenase enzymes are inactivated, then there will be no fixation of nitrogen in legumes.