The enzyme nitrogenase is highly sensitive to the molecular oxygen as it requires anaerobic condition. In nodule anaerobic condition is provided by

Options

A. Nod factor
B. bacteroids
C. Leghaemoglobin
D. Auxin

Answer

To solve the question regarding how anaerobic conditions are provided in the nodules for the enzyme nitrogenase, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Nitrogenase**:
- Nitrogenase is an enzyme that catalyzes the conversion of atmospheric nitrogen (N₂) into ammonia (NH₃). This process is known as nitrogen fixation.
- It is crucial to note that nitrogenase is highly sensitive to molecular oxygen (O₂) and requires an anaerobic (oxygen-free) environment to function effectively.

2. **Role of Root Nodules**:
- Root nodules are specialized structures formed by the symbiotic relationship between certain plants (like legumes) and nitrogen-fixing bacteria (such as Rhizobium).
- These nodules provide a habitat for the bacteria where nitrogen fixation occurs.

3. **Anaerobic Conditions in Nodules**:
- The question asks how these nodules maintain anaerobic conditions necessary for nitrogenase to function.
- In the nodules, a special protein called leghemoglobin is present.

4. **Function of Leghemoglobin**:
- Leghemoglobin acts similarly to hemoglobin in animals, binding to oxygen.
- However, its primary role in the nodule is to scavenge and regulate oxygen levels, preventing free oxygen from interfering with the nitrogenase enzyme.

5. **Conclusion**:
- Therefore, the correct answer to the question is that anaerobic conditions in the nodule are provided by **Leghemoglobin** (Option C). This protein binds oxygen and ensures that nitrogenase can operate without the detrimental effects of oxygen.

### Final Answer:
**C - Leghemoglobin**