[Campbell Biology P.835] Based on the text and Figure 36.4, would a higher leaf area index L... | Practice Question

Based on the text and Figure 36.4, would a higher leaf area index LAI always increase the amount of photosynthesis?

  • A: Yes, because more leaf surface area always means more light absorption.
  • B: No, because after a certain point, increased leaf layers can lead to self-shading, causing lower leaves to photosynthesize less than they respire, and potentially undergo self-pruning.
  • C: Yes, because a higher LAI indicates a larger plant, which inherently has higher photosynthetic capacity.
  • D: No, because the leaf area index only measures surface area and does not account for the availability of water or CO2.

Explanation

The text explains that while higher LAI can increase light capture, too many layers of leaves can lead to self-shading, where lower leaves photosynthesize less than they respire. In such cases, these nonproductive leaves or branches may undergo self-pruning, meaning a higher LAI does not always translate to increased overall photosynthesis.