Question

Terrestrial plants conduct gas exchange through stomata. Having only few stomata on the leaf surface is a common adaptation to which one of the following conditions?

• A. High aridity
• B. High pH
• C. Low UV radiation
• D. Low soil nitrogen

Hint:

To link plant adaptations to environmental conditions:
1. In arid environments, adaptations like fewer stomata and thick cuticles help conserve water.
2. Always relate the adaptation to the primary environmental stressor.
3. Consider stomatal density changes as a mechanism to balance gas exchange and water conservation.

Answer 1

The Correct Option is A

Step 1: Understand stomatal function. Stomata are small openings on the leaf surface that allow for gas exchange, including the uptake of carbon dioxide for photosynthesis and the release of oxygen. However, water vapor is also lost through stomata in a process known as transpiration. Step 2: Analyze the adaptation of having fewer stomata. In environments with high aridity (extremely dry conditions), plants must conserve water to survive. Having fewer stomata on the leaf surface reduces water loss through transpiration, which is a critical adaptation in such environments. Step 3: Evaluate the options. Option (A): Correct. High aridity creates water scarcity, and reducing the number of stomata helps minimize water loss.
Option (B): Incorrect. High pH is a soil condition that affects nutrient availability, not stomatal density.
Option (C): Incorrect. Low UV radiation does not necessitate an adaptation involving stomata.
Option (D): Incorrect. Low soil nitrogen affects nutrient uptake and growth but does not directly influence stomatal density.