Examining ozone effects on the tropical C4 crop Sorghum bicolor.

Ozone (O₃), a major air pollutant, can negatively impact plant growth and yield. While O₃ impacts have been widely documented in crops such as wheat and soybean, few studies have looked at the effects of O₃ on sorghum, a C₄ plant and the fifth most important cereal crop worldwide. We exposed grain sorghum (Sorghum bicolor cv. HAT150843) to a range of O₃ concentrations (daytime mean O₃ concentrations ranged between 20 and 97 ppb) in open-top chambers, and examined how whole plant and leaf morphological traits varied in response to O₃ exposure. Results showed no significant impact of realistic O₃ exposure on whole plant biomass and its partitioning in sorghum. These findings suggest that sorghum is generally resistant to O₃ and should be considered as a favourable crop in O₃ polluted regions, while acknowledging further research is needed to understand the mechanistic basis of O₃ tolerance in sorghum.