What Makes Corn a C4 Plant and How Does that Affect Corn Growth?

June 23, 2021

Not all plants are created equally when it comes to photosynthesis. In our world of corn and soybean while a soybean plant seems like it takes forever to get going and get growing.

The simplest way to define the differences is to look at the mechanisms in which the corn plant conducts photosynthesis and captures carbon. The utilization of carbon dioxide (CO2) is the biggest differentiation between a C3 (soybean) and C4 (corn) plant. Soybean plants use a respiration process that corn plants do not, which reduces photosynthetic efficiency by about 25 percent. Due to the pathways in corn plants and the enzymes needed, corn plants become more efficient as temperatures and sunlight increase.

Increased water use efficiency and nitrogen efficiency is also a characteristic of corn plants due to the enzymes produced in energy transfer versus a soybean plant. Stressful growing conditions that cause plants to close leaf stomata can impact soybean plants negatively compared to corn plants that can remain efficient even during stressful environmental conditions. When we feel uncomfortable with high temperatures (up to 86 degrees), bright sunlight, and, high humidity, a corn plant can respond with efficient growth.

Daniel Lundeen

Technical Agronomist


Wang, C., Guo, L., Li, Y., and Wang, Z. 2012. Systematic comparison of C3 and C4 plants based on metabolic network analysis. Proceedings of the 23rd International Conference on Genome Informatics (GIW 2012). BMC Systems Biology 6, S9. https://bmcsystbiol.biomedcentral.com/articles/10.1186/1752-0509-6-S2-S9.

C4 plants. Biological principles. Georgia Tech University. https://bioprinciples.biosci.gatech.edu/10-c4-plants/

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