Which of the following is the function of potassium?
(a) Cation-anion balance in cell
(b) Involved in starch synthesis.
(c) Activation of enzyme
(d) Opening and closing of stomata.
(e) Maintenance of turgidity of cell

Options

A. All except (a)
B. All except (a) and (b)
C. All except (c)
D. All of above

Answer

To determine the function of potassium from the given options, let's analyze each one step by step:

### Step 1: Understand the Role of Potassium
Potassium is an essential macronutrient for plants. It plays a crucial role in various physiological processes.

### Step 2: Analyze Each Option
1. **Cation-anion balance in cell**: Potassium helps maintain the balance of cations and anions, which is vital for cellular functions.

2. **Involved in starch synthesis**: While potassium does not directly synthesize starch, it plays a role in the overall metabolic processes that may affect starch synthesis.

3. **Activation of enzyme**: Potassium acts as an activator for certain enzymes, facilitating various biochemical reactions.

4. **Opening and closing of stomata**: Potassium ions are critical for the regulation of stomatal movement, which controls gas exchange and transpiration in plants.

5. **Maintenance of turgidity of cell**: Potassium helps in maintaining cell turgidity by regulating osmotic pressure within the cells.

### Step 3: Conclusion
Based on the analysis, all the functions listed in the options are indeed associated with potassium. Therefore, the correct answer is that potassium has multiple functions, including all the options provided.

### Final Answer
The function of potassium includes:
- (a) Cation-anion balance in cell
- (b) Involved in starch synthesis
- (c) Activation of enzyme
- (d) Opening and closing of stomata
- (e) Maintenance of turgidity of cell

Thus, the correct option is **(d) Opening and closing of stomata**, as it is one of the primary functions of potassium.

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