刺槐苗木抗氧化保护系统对石油污染的响应

Reponse of Anti-oxidation Protective System of Robinia pseudoacacia Seedlings to Petroleum Contamination

为探究刺槐（Robinia pseudoacacia）抗氧化保护系统在石油污染逆境下的适应性调节机制，采用盆栽试验研究了0，5，10，15，20g／kg浓度石油处理下1年生刺槐苗木的抗氧化保护酶系、抗氧化剂以及过氧化氢H2O2和丙二醛MDA含量的动态变化。结果表明：在5～20g／kg石油浓度处理30d时，除抗坏血酸过氧化物酶（APX）外，刺槐苗木的超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和谷胱甘肽还原酶（GR）活性和还原型谷胱甘肽（GSH）含量较对照显著降低，抗坏血酸（AsA）和类胡萝h素（Car）含量则基本维持稳定，而在20g／kg石油浓度下显著增加；随石油污染浓度的增加和时间延长（60～90d），SOD、CAT活性和AsA、GSH含量基本高于或等于对照，APX、GR活性以及Car含量则随石油浓度增加显著降低。石油污染后刺槐苗木H2O2较对照显著增加，MDA含量均等于或显著低于对照水平。刺槐苗木抗氧化保护系统在20g／kg浓度以内的石油处理下受损伤程度不明显。维持抗氧化剂含量以及抗氧化保护酶系一抗氧化剂的协同作用分别为刺槐石油污染短期和长期内清除活性氧的主要机制。

In order to investigate the self-adjusting adaptability mechanism of the anti-oxidation protective system of Robinia pseudoacacia seedings under petroleum contamination stress, the dynamic changes of anti-oxidation enzymes, antioxidants and the contents of hydrogenperoxide Hz 02 and malondialdehyde MDA of one year old Robinia pseudoacacia seedlings in pot experiment were measured. The results showed that except ascrodate peroxidase （APX） activity, the activities of superoxide dismutase （SOD）, catalase （CAT） and glu- tathione reductase （GR） and glutathione （GSH） content of Robinia pseudoacacia seedings were significantly lower than the control under the stress of 5-20 g/kg petroleum contamination for 30 days. The contents of ascorbicacid （AsA） and carotenoid （Car） remained stable at the same conditions and they became significant- ly higher than CK after stressed by 20 g/kg petroleum contamination for 30 days. Along with the increase of petroleum concentration and the stress duration （60-90 d）, SOD and CAT activities and AsA and GSH contents generally became higher or equal to control level, while APX and GR activities and Car content decreased significantly over the increase of petroleum concentration. After stressed by petroleum contamination, H20z contents of seedings significantly increased while MDA contents were equal to or lower than that of control. The destruction of anti-oxidation protective system of Robinia pseudoacacia seedings of petroleum contamination below 20 g/kg concentration was not obvious. Antioxidants content maintenance and the synergistic effects of anti oxidation enzymes and antioxidants could be obsverved as the main mechanisms under short- and long-term of petroleum contamination stress, respectively.