While in N, K and Mg deficiency, chlorosis appears first in ____leaves, in S and Ca deficiency,_____lveaves are the first to be affected

Options

A. young, old
B. old, young
C. old, old
D. young, young

Answer

**Step-by-Step Solution:**

1. **Understanding Mineral Mobility:**
- Minerals in plants can be classified as mobile or immobile. Mobile minerals can be transferred from older leaves to newer leaves, while immobile minerals remain in the location where they are formed.

2. **Identifying the Elements:**
- The question mentions deficiencies in sodium (Na), potassium (K), and magnesium (Mg). These elements are known to be mobile within the plant.
- It also mentions deficiencies in sulfur (S) and calcium (Ca), which are considered immobile elements.

3. **Effects of Deficiencies:**
- In the case of Na, K, and Mg deficiencies, since these are mobile elements, the plant will first show chlorosis (yellowing of leaves) in the older leaves. This is because the plant reallocates these nutrients to support the growth of new leaves.
- Conversely, for S and Ca deficiencies, since these elements are immobile, the chlorosis will first appear in the younger leaves. This is because the nutrients cannot be moved from older leaves to new growth.

4. **Conclusion:**
- Therefore, the answer to the question is:
- In Na, K, and Mg deficiency, chlorosis appears first in **older leaves**.
- In S and Ca deficiency, chlorosis appears first in **younger leaves**.

**Final Answer:**
- In N, K, and Mg deficiency, chlorosis appears first in **older leaves**, and in S and Ca deficiency, chlorosis appears first in **younger leaves**.

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