The ion which shows active efflux from guard cells during day time in a photoactive stomata

Options

A. Chlorine
B. Potassium
C. Malate
D. `H^(+)` ions

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks which ion shows active efflux from guard cells during the daytime in photoactive stomata.

2. **Defining Key Terms**:
- **Efflux**: This refers to the movement of ions or molecules out of a cell. In contrast, influx refers to the movement into a cell.
- **Guard Cells**: These are specialized cells that surround the stomata (pores) in plant leaves and regulate their opening and closing.

3. **Function of Guard Cells**: During the daytime, guard cells take in water, which causes them to swell and open the stomata, allowing gas exchange (CO2 in, O2 out) necessary for photosynthesis.

4. **Identifying Ion Movement**: The question specifically asks for the ion that is actively transported out of the guard cells during the day.

5. **Analyzing the Options**:
- **Chloride (Cl-)**: Generally involved in stomatal movement but not primarily responsible for efflux during the day.
- **Potassium (K+)**: Typically, potassium ions move into guard cells during the day to help them swell and open the stomata.
- **Malate**: This is an organic acid that can also play a role in guard cell function but is not primarily responsible for efflux.
- **H+ (Hydrogen ions)**: During the day, H+ ions are actively transported out of the guard cells, which helps in maintaining the osmotic balance and contributes to the opening of the stomata.

6. **Conclusion**: The ion that shows active efflux from guard cells during the daytime in photoactive stomata is **H+ (Hydrogen ions)**.

**Final Answer**: H+ ions

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