叶面喷施不同浓度稀土对橡胶树树叶抗氧化能力的影响

以橡胶树为材料,用0（CK）、0.05、0.10、0.20、0.40 g/L浓度稀土喷施橡胶树叶面3 d,研究橡胶树树叶和胶乳过氧化氢（H₂O₂）含量、树叶丙二醛（MDA）含量以及超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）活性。结果表明：0.10 g/L稀土处理橡胶树叶面,树叶和胶乳H₂O₂含量、树叶MDA含量达到最大值,分别为对照（CK）的168%、156%、518%;0.05 g/L稀土处理橡胶树叶面,树叶POD活性为对照（CK）的7.35倍;随稀土浓度的升高,树叶和胶乳H₂O₂含量、树叶MDA含量出现先上升后下降的趋势,SOD、POD活性也呈现类似的趋势,而稀土对CAT活性则有明显的抑制作用。相关性分析表明,不同浓度稀土处理橡胶树叶面,胶乳H₂O₂含量、树叶H₂O₂和MDA含量之间呈显著正相关;胶乳H₂O₂含量、树叶H₂O₂含量与树叶POD活性呈一定负相关;树叶CAT、SOD活性与胶乳H₂O₂含量呈一定负相关,而与树叶H₂O₂含量无相关性。表明适度浓度（0.05~0.10 g/L）的稀土处理能够提高橡胶树抗氧化酶活性,清除活性氧自由基,缓解外界刺激对细胞膜氧化损伤,从而提高抵御外界刺激的能力。

Effects of Foliar Application of Different Concentrations of Rare Earth on Antioxidant Capacity of Rubber Tree

The content of latex hydrogen peroxide(H2O2),malondialdehyde(MDA),superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT)of the leaves of rubber trees after spraying rare earth with 0,0.05,0.10,0.20 and 0.40 g/L for three days was studied.When rare earth(0.10 g/L)was used,the content of H2O2 of the leaves and latex,MDA of the leaves reached the maximum level,which was 168%,156%and 518%of the control group respectively.When rare earth(0.05 g/L)was used,the POD activity of the leaves was 7.35 times than that of the control group.With increasing the rare earth concentration,the H2O2 content of the leaves and latex,and the MDA content of the leaves increased first and then decreased.The activities of SOD and POD also had a similar tendency,while the rare earth had a significant inhibitory effect on the activity of CAT.The correlation analysis showed that there was a significant positive correlation between the H2O2 content of the latex and leaves,and the MDA content of the leaves when they were treated at different concentrations.The H2O2 content of latex and leaves was negatively correlated with the POD activity of the leaves.The CAT activity and SOD of the leaves were negatively correlated with the H2O2 content of the latex,but had nothing with the H2O2 content of the leaves.The results illustrated that moderate concentration treatment(0.05-0.10 g/L)of rare earth could improve the antioxidant activity of rubber trees,scavenge reactive oxygen species,and alleviate the oxidative damage of cell membrane by external stimulation,thus improving the ability to resist external stimuli.