Which one of the following elements in plants is not remobilised?

Options

A. Phosphorus
B. Calcium
C. Potassium
D. Sodium

Answer

To solve the question "Which one of the following elements in plants is not remobilised?", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Remobilization**:
- Remobilization refers to the ability of certain nutrients to move from one part of the plant to another, especially when there is a deficiency in a specific area. This is crucial for the plant's growth and development.

2. **Identify Mobilized and Immobilized Nutrients**:
- Mobilized nutrients are those that can be translocated within the plant. Examples include nitrogen, phosphorus, and potassium.
- Immobilized nutrients, on the other hand, do not remobilize once they are assimilated. They either remain in their location or move very little.

3. **Evaluate the Given Options**:
- The question provides several options, and we need to identify which one is not remobilized.
- Common nutrients that are mobilized include:
- **Nitrogen**: Highly mobile and can be moved to areas of deficiency.
- **Phosphorus**: Also mobile and can be translocated as needed.
- **Potassium**: Known for its mobility in plants.
- We need to look for an element that is known to be immobilized.

4. **Identify the Correct Answer**:
- Among the options, **Calcium** is the element that is not remobilized. Once calcium is incorporated into the plant structure, it does not move to areas where there may be a deficiency.
- Other options like sodium are not essential for most plants, but they are not the focus of this question.

5. **Conclusion**:
- Therefore, the answer to the question is **Calcium** (Option 2), as it is the element that is not remobilized in plants.

### Final Answer:
**Calcium (Option 2)** is the element in plants that is not remobilized.