By Andi Anderson
Crop scientists at the University of Illinois Urbana-Champaign and the USDA Agricultural Research Service have discovered that soybeans face serious damage from both drought and ozone pollution, two growing challenges linked to climate change.
For years, scientists questioned whether drought could shield plants from ozone harm by forcing leaves to close tiny openings called stomata. When stomata close, they conserve water and could theoretically block ozone from entering. However, the study proved this is not the case. Researchers found that soybean yields suffered from ozone exposure even during drought conditions.
The research team grew soybeans in field conditions for three years at the SoyFACE research site. Plants were exposed to ozone levels of 100 parts per billion, similar to levels seen in parts of Asia, while also receiving 40 percent less rainfall. The results showed that ozone consistently reduced photosynthesis and yield, producing fewer and smaller seeds.
Hormone signaling was also studied, particularly the drought-related hormone abscisic acid. The findings showed that drought responses remained normal, yet ozone still entered the leaves and caused damage. Researchers explained that stomata rarely close completely, leaving an entry point for ozone to trigger harmful reactions inside plant cells.
Even though ozone levels in the U.S. Corn Belt are lower, damage can occur at levels as low as 40 parts per billion. These concentrations are already common during growing seasons and are expected to increase through 2070. Researchers caution that farmers may mistake ozone symptoms for other plant diseases.
Photo Credit: istock-oticki
Categories: Illinois, Crops, Corn, Soybeans, Weather