Question

Choose the correct answer from the alternatives given regarding $C_4$ plants

• A. store carbon dioxide temporarily as oxaloacetate
• B. are found in hot dry climates
• C. have a net photosynthetic rate two to three times that of $C_3$ plants
• D. all of the above

Answer 1

The correct option is D all of the above

Some plants that live in hot, dry climates maintain low oxygen levels in their leaves by keeping the stomata closed to prevent water loss. To get adequate CO₂for photosynthesis, C4 plants have adapted to photorespiration by modifying the Calvin-Benson cycle. In C4 plants photorespiration does not occur. This is because they have a mechanism that increases the concentration of CO2 at the enzyme site. The C4 pathway is certainly more efficient than the C3 pathway in the sense of carbon fixation. In C4 plants, cells are exposed to oxygen and have no RuBisCO to do photosynthesis. The CO2 joins with another carbon compound to make a C4 chemical called oxaloacetic acid.

So, the correct option is, 'all of the above'.