Differences in the photosynthetic “machinery” of certain crop plants can make them more or less prone to harm caused by ground-level ozone pollution. The research was developed by USDA’s Agricultural Research Service and University of Illinois scientists in Urbana-Champaign.
The findings—that so-called “C4” crops like corn and sorghum tolerate increased ozone levels better than “C3” crops, like rice or snap beans—open the door to better models for predicting crop responses to the effects of global climate change, as well as developing more resilient varieties that can sustain humanity’s increasing demand for food, feed, fiber and fuel. While both C3 and C4 crops use the enzyme called rubisco to convert carbon dioxide into sugars, C4 crops isolate rubisco in specialized cells where the concentration of carbon dioxide is very high. This enables higher rates of photosynthesis and greater efficiency of water use. Thus, C4 plants have lower stomatal conductance, resulting in less diffusion of carbon dioxide and ozone into leaves.
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