Stomata open during day due to

Options

A. Accumulation of K^(+) ion and suger
B. High pH
C. Osmotic effect of ions present in guard cells
D. None of the above

Answer

**Step-by-Step Solution:**

1. **Understanding Stomata Function**: Stomata are small openings on the surface of leaves that allow for gas exchange. They play a crucial role in photosynthesis and transpiration.

2. **Photosynthesis During Daytime**: During the day, plants undergo photosynthesis, a process that converts carbon dioxide and water into glucose and oxygen using sunlight. This process occurs primarily in the chloroplasts of plant cells.

3. **Glucose Accumulation**: As photosynthesis occurs, glucose accumulates in the plant cells, including the guard cells that surround the stomata. This accumulation is significant because it affects the osmotic pressure within the cells.

4. **Increase in Cell Sap**: The accumulation of glucose leads to an increase in the concentration of solutes in the guard cells. This causes water to move into the guard cells by osmosis, increasing the volume of cell sap.

5. **Turgidity of Guard Cells**: As the volume of cell sap increases, the guard cells become turgid (swollen with water). This turgidity is essential for the opening of the stomata.

6. **Role of Potassium Ions**: During the day, there is also an influx of potassium ions (K+) into the guard cells. The movement of these ions into the cells contributes to the increase in osmotic pressure, further enhancing turgidity.

7. **Conclusion**: The stomata open during the day primarily due to the accumulation of glucose and potassium ions, which increase the osmotic pressure and turgor pressure in the guard cells, causing them to swell and open the stomata.

**Final Answer**: Stomata open during the day due to the accumulation of glucose and potassium ions, which increase osmotic pressure and turgor pressure in the guard cells.

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