Question

Stomatal movement is not affected by

• A. Temperature
• B. O₂ concentration
• C. Light
• D. CO₂ concentration

Answer 1

The Correct Option is B

Stomatal movement refers to the opening and closing of stomata, which are tiny openings on the surfaces of leaves. This process is crucial for gas exchange, allowing carbon dioxide (CO₂) to enter for photosynthesis and releasing oxygen (O₂). Several environmental factors influence stomatal movement, and understanding these is important for questions related to plant physiology. Let's analyze each option:

1. Temperature: Stomatal movement is significantly affected by temperature. High temperatures can lead to increased transpiration and may cause stomata to close to prevent excessive water loss.
2. O₂ concentration: Oxygen concentration does not directly impact stomatal movement. Stomata primarily respond to the need for CO₂ intake for photosynthesis rather than fluctuations in oxygen levels.
3. Light: Light is a primary factor affecting stomatal opening. In general, stomata open in light to facilitate photosynthesis and close in darkness.
4. CO₂ concentration: Stomatal movement is directly affected by the concentration of carbon dioxide. Low levels of CO₂ inside the leaf cause the stomata to open, while high levels may cause them to close.

From the analysis above, it is evident that:

• Temperature, light, and CO₂ concentration all influence stomatal movement.
• However, O₂ concentration does not directly affect this process.

Conclusion: The correct answer is O₂ concentration, as it does not directly influence stomatal movement.