What is the purpose of carbon dioxide in plant growth?

• A. Increase plant yields
• B. Control pests
• C. Burn leaves
• D. Decrease yields

Answer: (A)

Carbon dioxide provides the building blocks for photosynthesis, the process plants use to turn light into sugars that fuel growth. When CO2 is available in higher concentrations, photosynthesis can proceed more quickly, producing more carbohydrates that support faster growth and larger yields—assuming light, temperature, water, and nutrients are also adequate. This is why CO2 enrichment is used in greenhouses to boost production. It isn’t a method for pest control, it doesn’t burn leaves, and increasing CO2 under well-managed conditions wouldn’t decrease yields; the benefit depends on having sufficient light and other resources. But keep in mind the effect levels off if any other factor becomes limiting, so the yield gains are conditional on the whole growing environment being favorable.