In arid (dry) environments, which photosynthetic strategy is most directly associated with improved water-use efficiency due to stomata opening primarily at night?

• A. All plants regardless of photosynthetic strategy
• B. C3 plants
• C. CAM plants
• D. C4 plants

Answer: (C)

Verified step by step guidance

1. Understand that water-use efficiency in plants refers to the amount of carbon dioxide fixed into sugars per unit of water lost through transpiration.
2. Recall that stomata are pores on the leaf surface that allow gas exchange; opening stomata during the day can lead to significant water loss, especially in arid environments.
3. Identify the photosynthetic strategies: C3, C4, and CAM plants, each with different adaptations to minimize water loss.
4. Recognize that CAM (Crassulacean Acid Metabolism) plants open their stomata primarily at night to fix CO2, reducing water loss during the hot, dry daytime.
5. Conclude that CAM plants are most directly associated with improved water-use efficiency in arid environments due to their nocturnal stomatal opening.