On hot days, what mechanism do C3, C4, and CAM plants use to reduce water loss?

• A. Absorb more sunlight
• B. Increase photosynthesis rate
• C. Open their stomata wider
• D. Close their stomata

Answer: (D)

Verified step by step guidance

1. Understand the role of stomata: Stomata are small openings on the surface of leaves that allow for gas exchange. They play a crucial role in photosynthesis by letting carbon dioxide in and oxygen out, but they also allow water vapor to escape, which can lead to water loss.
2. Recognize the challenge of hot days: On hot days, plants face increased risk of water loss due to higher temperatures and potentially lower humidity. This can lead to dehydration if not managed properly.
3. Identify the mechanism used by plants: To reduce water loss, plants can close their stomata. This action minimizes the escape of water vapor, helping the plant conserve water during hot conditions.
4. Differentiate between plant types: C3, C4, and CAM plants have different strategies for photosynthesis and water conservation. C3 plants typically close their stomata during the hottest part of the day. C4 plants have a specialized mechanism that allows them to photosynthesize efficiently even when stomata are partially closed. CAM plants open their stomata at night to reduce water loss.
5. Connect the mechanism to the problem: Closing stomata is a common strategy among C3, C4, and CAM plants to reduce water loss on hot days. This adaptation helps them survive in environments where water conservation is crucial.