Excess of Mn causes deficiency of -

Options

A. Fe
B. Mg
C. Ca
D. All

Answer

**Step-by-Step Solution:**

1. **Understanding Manganese as a Micronutrient:**
- Manganese (Mn) is classified as a micronutrient, which means it is required by plants in small amounts for proper growth and development.

2. **Effects of Excess Manganese:**
- When manganese is present in excess, it can lead to a condition known as "acid soil." This condition can negatively affect the availability of other essential nutrients.

3. **Competition for Nutrient Uptake:**
- Excess manganese competes with other micronutrients, particularly iron (Fe) and magnesium (Mg), for uptake by plant roots. This competition can lead to deficiencies of these nutrients in the plant.

4. **Inhibition of Calcium Translocation:**
- Excess manganese also inhibits the translocation of calcium (Ca) to the shoot apex. Calcium is crucial for various physiological functions in plants, and its deficiency can lead to various growth issues.

5. **Identifying Deficiencies:**
- Given the competitive nature of manganese with iron and magnesium, as well as its inhibitory effect on calcium translocation, we can conclude that excess manganese can cause deficiencies of:
- Iron
- Magnesium
- Calcium

6. **Conclusion:**
- Therefore, the correct answer to the question is that excess manganese causes deficiencies of iron, magnesium, and calcium. Thus, the answer is option 4: all.

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