Question

For the same amount of $C{O}_2$ fixed, a $C_4$ plant in comparison with a $C_3$ plant loses only

• A. Half amount of water
• B. Equal amount of water
• C. Double amount of water
• D. None of the above

Answer 1

Answer: (A)

Half amount of water

For C${}_3$ plants, photorespiration is a significant problem during which these plants close their stomata to conserve water. The CO${}_2$ grabbed is directly transferred to RUBISCO and not allowing the oxygen to photo-respiration. Thus only half amount of water is lost.