Select the incorrect statement :-

Options

A. `Zn^(2+)`is needed for Auxin synthesis
B. Fe is activator for catalase enzyme
C. K is required in more abundant amount in meristematic tissue, buds, leaves and roots tips
D. `Ca^(++)` & `Cl^(–)` are mainly related to cation anion balance

Answer

To solve the question of selecting the incorrect statement regarding plant physiology, specifically in the context of micronutrients and their roles, we can analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement Analysis**:
- **Statement 1**: "Zinc ion is needed for auxin synthesis."
- **Evaluation**: Zinc is indeed a micronutrient that plays a role in various metabolic processes, including the synthesis of auxins, which are important plant hormones. This statement is **true**.

2. **Statement 2**: "Iron is an activator for catalase enzyme."
- **Evaluation**: Iron is required by plants in the form of ferric ions (Fe3+) and is known to be an activator for the catalase enzyme, which helps in breaking down hydrogen peroxide. This statement is also **true**.

3. **Statement 3**: "Potassium is required in more abundant amounts in meristematic tissue, buds, leaves, and root tips."
- **Evaluation**: Potassium is essential for various physiological functions in plants, including maintaining turgidity and facilitating the opening and closing of stomata. This statement is **true**.

4. **Statement 4**: "Calcium ions and chloride ions are mainly related to cation and ion balance."
- **Evaluation**: While calcium ions are important for cell wall structure and signaling, and chloride ions play a role in photosynthesis and osmotic balance, they do not primarily maintain cation and ion balance in the same way potassium does. Therefore, this statement is **incorrect**.

### Conclusion:
The incorrect statement is **Statement 4**: "Calcium ions and chloride ions are mainly related to cation and ion balance."

---