Which one of the following symptoms is not due to manganese toxicity in plants?

Options

A. Calcium translocation in shoot spex is inhibited
B. Deficiency in both iron and nitrogen is induced
C. Appearance of brown spot surrounded by chlorotic veins.
D. none of the above

Explanation

To determine which symptom is not due to manganese toxicity in plants, we need to analyze the symptoms provided and understand the effects of manganese toxicity.

### Step-by-Step Solution:

1. **Understand Manganese Toxicity**: Manganese is an essential micronutrient for plants, but in high concentrations, it can become toxic. Symptoms of manganese toxicity typically include chlorosis (yellowing) of leaves, particularly between the veins, and the appearance of brown spots.

2. **Evaluate the Symptoms**: The question presents four symptoms. We need to evaluate each one to see if it is associated with manganese toxicity or not.

3. **Analyze Each Option**:
- **Option A**: Calcium translocation in shoot apex. Manganese toxicity can lead to calcium deficiency, which could affect calcium translocation. This symptom could be related to manganese toxicity.
- **Option B**: Brown spots with chlorotic veins. This is a classic symptom of manganese toxicity, indicating that this option is indeed due to manganese toxicity.
- **Option C**: Deficiency in both iron and nitrogen. Manganese toxicity does not directly cause deficiencies in iron and nitrogen; rather, it can lead to an imbalance in nutrient uptake. Therefore, this symptom is not due to manganese toxicity.
- **Option D**: Other symptoms related to manganese toxicity, such as leaf curling or necrosis, could also be present, but we are focusing on the options given.

4. **Conclusion**: Based on the analysis, the symptom that is not due to manganese toxicity is **Option C: Deficiency in both iron and nitrogen**.

### Final Answer:
The symptom that is not due to manganese toxicity in plants is **Deficiency in both iron and nitrogen**.