The deficiency symptoms of which of the following nutrienst are visible first in the senescent leaves?

Options

A. Nitrogen, potassium and calcium
B. Boron, calcium and magnesium
C. Potassium nitrogen and magnesium
D. Sulphur, boron and potassium

Answer

To determine which nutrient deficiency symptoms are visible first in senescent leaves, we can follow these steps:

### Step-by-Step Solution:

1. **Identify Nutrients and Their Deficiency Symptoms**:
- Start by listing the nutrients mentioned: Potassium, Nitrogen, Calcium, and Magnesium.
- Understand that the deficiency symptoms of certain nutrients manifest in older leaves first.

2. **Analyze Potassium Deficiency**:
- Potassium deficiency leads to yellowing of leaves and the appearance of brown patches. This symptom is often seen in older leaves first.

3. **Analyze Nitrogen Deficiency**:
- Nitrogen deficiency also causes yellowing of leaves, particularly affecting older leaves as the plant reallocates nitrogen to younger leaves.

4. **Analyze Magnesium Deficiency**:
- Magnesium deficiency results in yellowing of leaves as well, typically starting in older leaves.

5. **Analyze Calcium Deficiency**:
- Calcium deficiency symptoms usually appear in younger leaves first, not in senescent leaves.

6. **Eliminate Options**:
- Based on the analysis, we can eliminate Calcium as it does not show symptoms in senescent leaves.
- Both Potassium and Nitrogen show symptoms in older leaves, as does Magnesium.

7. **Conclusion**:
- Since Potassium, Nitrogen, and Magnesium deficiencies can all manifest in senescent leaves, the correct answer is the option that includes these three nutrients.

### Final Answer:
The deficiency symptoms of Potassium, Nitrogen, and Magnesium are visible first in senescent leaves.