Effects of Elevated O3 and/or Elevated CO2 on Lipid Peroxidation and Antioxidant Systems in Ginkgo biloba Leaves

Four-year-old seedlings of Ginkgo biloba were exposed to elevated O₃, elevated CO₂ and elevated O₃ plus elevated CO₂ in open-top chambers (OTCs) to study the responses of antioxidant system in Ginkgo biloba leaves. No significant changes in reactive oxygen production and scavenging systems were detected in seedlings exposed to high CO₂. Significant increase in H₂O₂ and MDA content were induced by elevated O₃. The ascorbate content and antioxidative enzymes activity were increased significantly by exposure to high O₃ as well. But the promoted ability in scavenging did not prevent the increase in H₂O₂ content and cell membrane lipid peroxidation. The increase was mitigated by high CO₂ in the combined exposure, but the effect was hardly significant.