What would be the expected effect on plants if the atmospheric CO₂ concentration was doubled?
A) All plants would have faster growth rates.
B) C3 plants would have faster growth rates; C4 plants would be minimally affected.
C) C4 plants would have faster growth rates; C3 plants would be minimally affected.
D) C3 plants would have faster growth rates; C4 plants would have slower growth rates.

Question

Quizplus · Accepted Answer

C3 plants rely on the enzyme Rubisco to fix CO2, which becomes less efficient at higher concentrations of CO2. Therefore, they show only a slight increase in growth rates with elevated CO2 levels. C4 plants use different mechanisms to concentrate CO2 at Rubisco sites and are less affected by higher concentrations of atmospheric CO2. Therefore, they can grow faster under these conditions.

What Would Be the Expected Effect on Plants If the Atmospheric