Which of the following is not caused by deficiency of mineral ?

Options

A. Chlorosis
B. Etiolation
C. Shortening of internodes
D. Necrosis

Answer

To determine which of the following symptoms is not caused by a deficiency of minerals, we will analyze each option provided: chlorosis, etiolation, shortening of internodes, and necrosis.

### Step-by-Step Solution:

1. **Understanding Mineral Deficiencies**:
- Essential nutrients for plants are categorized into macronutrients (needed in large amounts) and micronutrients (needed in small amounts).
- Deficiencies in these nutrients can lead to various symptoms affecting plant growth and development.

2. **Analyzing Chlorosis**:
- Chlorosis is characterized by the yellowing of leaves due to the loss of chlorophyll.
- It is commonly caused by deficiencies in minerals such as nitrogen, potassium, magnesium, and sulfur.

3. **Analyzing Etiolation**:
- Etiolation occurs when plants are grown in partial or complete absence of light.
- It is characterized by long, weak stems and is not caused by a deficiency of mineral ions.

4. **Analyzing Shortening of Internodes**:
- Shortening of internodes can occur due to deficiencies in certain minerals, leading to stunted growth.
- This symptom is often associated with deficiencies in nutrients like nitrogen and potassium.

5. **Analyzing Necrosis**:
- Necrosis refers to cell death in plants and can be caused by deficiencies in minerals such as calcium, magnesium, and copper.
- This indicates that necrosis is indeed linked to mineral deficiencies.

6. **Conclusion**:
- Among the options provided, **etiolation** is the only symptom that is not caused by a deficiency of mineral ions. It is primarily a response to inadequate light rather than a lack of nutrients.

### Final Answer:
**Etiolation** is not caused by a deficiency of minerals.