The deficiency of which element causes the deficiency of nitrogen?

Options

A. Mo
B. K
C. Mn
D. S

Answer

To answer the question regarding which element's deficiency causes the deficiency of nitrogen, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Essential Elements**:
- Plants require certain elements for growth and development, known as essential elements. These are categorized into macronutrients (needed in larger amounts) and micronutrients (needed in smaller amounts).

2. **Identifying Nitrogen**:
- Nitrogen is classified as a macronutrient because it is required by plants in large quantities. It plays a crucial role in the formation of proteins and is absorbed by plants primarily in the form of nitrates.

3. **Role of Molybdenum in Nitrogen Metabolism**:
- Molybdenum is a micronutrient that is vital for nitrogen metabolism. It is absorbed by plants in the form of MoO2 2+ and is essential for the activation of specific enzymes involved in nitrogen metabolism.

4. **Key Enzymes**:
- The enzymes that are activated by molybdenum are nitrogenase and nitrate reductase. These enzymes are crucial for the conversion of atmospheric nitrogen into a form that plants can use.

5. **Consequences of Molybdenum Deficiency**:
- If there is a deficiency of molybdenum, the activation of nitrogenase and nitrate reductase is hindered. This leads to impaired nitrogen metabolism, resulting in a deficiency of nitrogen in the plant.

6. **Conclusion**:
- Therefore, the deficiency of molybdenum causes the deficiency of nitrogen in plants. The correct answer to the question is option **a) Molybdenum**.