Which one is a C4 plant?

The correct answer is Zea mays.

Concept:

• C4 plants are a group of plants that use the C4 carbon fixation pathway during photosynthesis. This pathway is an adaptation that enhances the efficiency of photosynthesis in conditions of high light intensity, high temperatures, and dryness.
• In C4 plants, carbon dioxide is first fixed into a 4-carbon compound, oxaloacetate, before entering the Calvin cycle. This is achieved by the enzyme PEP carboxylase, which has a higher affinity for CO₂ and does not interact with oxygen, thereby reducing photorespiration.
• C4 plants are commonly found in tropical and subtropical regions and include crops such as maize (Zea mays), sugarcane, sorghum, and certain grasses.

Explanation:

• Zea mays: Commonly known as maize or corn, Zea mays is a classic example of a C4 plant. It uses the C4 pathway for photosynthesis, which makes it highly efficient in converting sunlight into energy even under conditions of high temperature and light intensity. This adaptation is particularly beneficial for agricultural productivity in tropical regions.
• Oryza sativa (Incorrect): Oryza sativa, commonly known as rice, is a C3 plant. C3 plants use the Calvin cycle for carbon fixation. These plants are better suited to cooler, wetter conditions and are less efficient in high-temperature and dry environments due to higher rates of photorespiration.
• Allium cepa (Incorrect): Commonly known as onion, Allium cepa is also a C3 plant.
• Mangifera indica (Incorrect): Mangifera indica, commonly known as mango, is a C3 plant.