The loss of water in C₄ plants compared to C₃ plants for the same amount of CO₂ fixed is

Options

(a) Half
(b) one-third
(c) one-fourth
(d) double

Correct Answer:

one-third

Explanation:

The loss of water in C₄ plants compared to C₃ plants for the same amount of CO₂ fixed is one-third. C₄ plants have a competitive advantage over plants possessing the more common C₃ carbon fixation pathway under conditions of drought, high temperatures and nitrogen or CO₂ limitation. When grown in the same, environment, at 30°C, C₃ grasses lose approximately 833 molecules of water per CO₂ molecules that is fixed, whereas C₄ grasses lose only 277 water molecules per CO₂ moleculr fixed. This shows that the