The first stable product of fixation of atmospheric nitrogen in leguminous plants is

Options

A. `NO_3^-`
B. Glutamate
C. `NO_2^-`
D. Ammonia

Answer

To solve the question regarding the first stable product of nitrogen fixation in leguminous plants, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Nitrogen Fixation**:
- Nitrogen fixation is the process by which atmospheric nitrogen (N₂) is converted into a more usable form for plants. This process is crucial for the growth of plants, especially legumes.

2. **Role of Symbiotic Bacteria**:
- In leguminous plants, nitrogen fixation is primarily facilitated by symbiotic bacteria known as **Rhizobium**. These bacteria reside in root nodules of the plants.

3. **Process of Nitrogen Fixation**:
- The atmospheric nitrogen is converted into ammonia (NH₃) through the action of an enzyme called **nitrogenase** present in the Rhizobium bacteria.

4. **First Stable Product**:
- The first stable product formed during this nitrogen fixation process is **ammonia (NH₃)**. This is because ammonia is the immediate product of nitrogen fixation before it is further converted into other forms like nitrates (NO₃⁻) or amino acids.

5. **Conclusion**:
- Therefore, the first stable product of nitrogen fixation in leguminous plants is **ammonia (NH₃)**.

### Final Answer:
The first stable product of fixation of atmospheric nitrogen in leguminous plants is **ammonia (NH₃)**.

---