Question

Enhanced CO₂ concentration in environment would lead to ________ in plants.

• A. increased water uptake and reduced photosynthesis
• B. increased photosynthesis and increased water demand
• C. decreased photosynthesis and decreased water demand
• D. decreased Osubscript{2} emission and no change in photosynthesis

Hint:

Higher COsubscript{2} levels generally enhance photosynthesis rates, especially in C3 plants, and lead to greater water usage through increased transpiration.

Answer 1

The Correct Option is B

Step 1: Understand the role of CO₂ in photosynthesis.
CO₂ is a key reactant in photosynthesis. When its concentration increases, it boosts the rate of photosynthesis due to greater substrate availability for the Calvin cycle.
Step 2: Impact on water demand.
Increased photosynthesis means more stomatal activity and transpiration, which in turn increases water uptake by the plant. Thus, the water demand also increases.
Step 3: Evaluate options.
Option (1) is incorrect because photosynthesis increases, not decreases.
Option (2) correctly states both effects.
Option (3) contradicts the role of CO₂ in photosynthesis.
Option (4) is unrelated and does not explain the process accurately.