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 answer 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 form that plants can use. In leguminous plants, this process primarily occurs in root nodules.

2. **Role of Root Nodules**:
- Leguminous plants form root nodules when they are infected by specific nitrogen-fixing bacteria, such as Rhizobium. These nodules are specialized structures that house the bacteria responsible for nitrogen fixation.

3. **Enzyme Involved**:
- Inside the root nodules, there is an enzyme called nitrogenase. This enzyme plays a crucial role in the conversion of atmospheric nitrogen into ammonia.

4. **Conversion Process**:
- The nitrogenase enzyme facilitates a series of reactions where atmospheric nitrogen (N₂) is first reduced to diimide (N₂H₂), then to hydrazine (N₂H₄), and finally to ammonia (NH₃).

5. **Identifying the First Stable Product**:
- Among the products formed during this process, ammonia (NH₃) is the first stable product. It is a usable form of nitrogen for plants, while other forms like nitrates or nitrites are produced later in the nitrogen cycle.

6. **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)**.

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