[Effects of elevated carbon dioxide and ozone on the growth and secondary metabolism of spring wheat]

With open-top chamber (OTC), the effects of elevated CO2 (550 micromol x mol(-1)) and O3 (80 nmol x mol(-1)) and their combination on the biomass, total phenols, and flavone at different growth stages of spring wheat, as well as the yield components at maturity stage, were studied. The results showed that under elevated CO2, the biomass and yield components were significantly higher than those under ambient CO2 (342 micromol x mol(-1)), while under elevated O3, these parameters were significantly lower than those under ambient O3 (30 nmol x mol(-1)). The combination of elevated CO2 and O3 was at the intermediate place, indicating that CO2 could mitigate the negative effects of O3, while O3 could weaken the positive effects of CO2. Elevated CO2 and O3 increased the content of total phenols in wheat leaves, and the combination of elevated CO2 and O3 had the greatest effect. However, at late growth stage, the increment of total phenols was decreased. At early growth stage, the total content of leaf flavone under elevated CO2 and O3 and their combination was lower than the control, but at maturing stage, it was in adverse.