高浓度二氧化碳和臭氧对蒙古栎叶片活性氧代谢的影响

利用开顶箱熏蒸法，研究了高浓度O₃(≈80 nmol·mol^-1)和高浓度CO₂(≈700 μmol·mol^-1)及其复合处理对蒙古栎叶片活性氧代谢的影响.结果表明：高浓度O₃显著增加了蒙古栎叶片超氧阴离子(O₂^?)产生速率、过氧化氢(H₂O₂)和丙二醛(MDA)含量和电解质外渗率(P<0.05)，显著降低了超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性和抗坏血酸(AsA)含量(P<0.05).高浓度CO₂对蒙古栎叶片活性氧代谢影响不显著.高浓度O₃和CO₂复合处理的叶片O₂^?产生速率、H₂O₂和MDA含量和电解质外渗率上升不明显，说明高浓度CO₂缓解了高浓度O₃对蒙古栎叶片的氧化胁迫.复合处理的叶片SOD、CAT、APX活性以及AsA和总酚含量显著高于O₃处理的叶片(P<0.05)，说明高浓度CO₂缓解了高浓度O₃对叶片抗氧化系统的消极影响.

Effects of elevated CO_2 and O_3 on active oxygen metabolism of Quercus mongolica leaves.

By using open top chamber fumigation method, this paper studied the effects of elevated O₃ (≈80 nmol·mol^-1) and CO₂ (≈700 μmol·mol^-1), single and in combination, on the active oxygen metabolism of Quercus mongolica leaves. Elevated O₃ increased the superoxide anion radical (O₂) generation rate, hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) contents, and electrolyte leakage (EL) (P<0.05), but decreased the superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) activities and ascorbate (AsA) content (P<0.05); while elevated CO₂ had no significant effects on the active oxygen metabolism of Q. mongolica leaves. The combination of elevated O₃ and CO₂ had less effects on the O₂ generation rate, H₂O₂ and MDA contents, and EL, indicating that elevated CO₂ alleviated the oxidative stress of elevated O₃ on Q. mongolica leaves, but increased the SOD, APX, and CAT activities and the AsA and total phenol contents, compared with elevated O₃ (P<0.05), indicating that elevated CO₂ alleviated the negative effects of elevated O₃ on Q. mongolica leaf antioxidant system.