柠条抗氧化保护系统对干旱胁迫的响应

Responses of Antioxidation Protective System of Caragana korshinskii Kom.to Drought Stress

为阐明柠条（Caragana korshinskii Kom.）抗氧化保护系统在旱逆境下的适应性调节机制,采用盆栽试验,于2006年7-9月测定了不同土壤水分处理下1年生柠条苗超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）、谷胱甘肽还原酶（GR）活性及抗坏血酸（AsA）、还原型谷胱甘肽（GSH）、类胡萝卜素（Car）、过氧化氢（H2O2）、丙二醛（MDA）含量的动态变化。结果表明：与适宜水分条件相比,在中度及重度干旱胁迫下柠条的Car含量均长期无显著变化,CAT活性、GSH、AsA、H2O2和MDA含量均在一定时期显著增加（P〈0.05）;在中度干旱胁迫下SOD、APX和GR活性均长期无显著变化,但重度干旱胁迫下SOD与APX活性均有显著增加（P〈0.05）,GR活性则长期显著降低（P〈0.05）;在中度及重度干旱胁迫下柠条的CAT、AsA和GSH具有重要抗氧化保护作用,此外SOD与CAT良好的协同作用及中度干旱胁迫下AsA、GSH、GR与APX良好的协同作用下,能使对活性氧的清除更加有效;干旱诱导的氧化胁迫与氧化伤害在重度胁迫时更早发生。

Caragana korshinskii Kom.is a very important afforestation species in arid and semi-arid areas and its drought-resistant characteristics have received a lot of attention.There were many related researches on its morphological and anatomical structure characteristics,osmotic adjustment substances,water physiology and photosynthetic physiological characteristics under stresses.But the research on its antioxidation protective system was few.In order to clarify the adaptive regulating mechanism of antioxidation protective system to drought stress,some kinds of enzyme（SOD,CAT,APX and GR）,metabolites（AsA,GSH and Car） and H2O2,MDA involved in protective antioxidation of one-year-old C.korshinskii seedlings were measured under different soil moisture treatments using potted experiment from July to September.The results show that the Car content of C.korshinskii seedlings was at same level during the whole period and the CAT activity and GSH,AsA,H2O2,and MDA contents were significantly increased during a certain period under moderate or severe drought stress in comparison with suitable soil moisture treatment.The SOD,APX,and GR activities had no obvious changes under moderate drought stress,while SOD and APX activities increased and GR activity decreased under severe drought stress.These results indicate the CAT,AsA,and GSH had important protective function of antioxidation in C.korshinskii under moderate drought stress.The synergistic reactions between SOD and CAT and among SOD,CAT,APX,AsA and GSH under severe drought stress effectively facilitated the elimination of active oxygen.The oxidation stress and oxidation damage of C.korshinskii seedlings induced by drought stress occurred earlier under severe drought stress than moderate drought stress.