钾水平对巴西橡胶树幼苗MDA含量和保护酶活性的影响

Influence of Potassium Levels on MDA Content and Activities of Protective Enzymes on Hevea brasiliensis Seedlings

采用水培技术研究不同钾水平对RRIM600无性系种子实生幼苗各器官MDA含量和保护酶活性的影响。结果表明:在低钾胁迫下,除叶部的K0、K1、K10处理、根中的K10、K50处理外,缺钾降低了巴西橡胶树幼苗各器官中MDA含量,但各器官中各处理间MDA含量差异不显著;除叶部的K0处理、茎部的皮和根中K50处理外,缺钾降低了各器官中SOD酶活性,且在叶部SOD酶活性显著降低;除叶部的K1、K10、K50处理、根中的K1处理外,缺钾降低了各器官中POD酶活性,但各器官中各处理间POD酶活性差异不显著;缺钾极显著提高了巴西橡胶树幼苗叶片CAT酶活性。因此,在巴西橡胶树幼苗各器官中抵御低钾胁迫主要靠各种保护酶相互协调来完成。

The young RRIM600 seedlings of Hevea brasiliensis were cultured in solution containing different levels of potassium（K2O; 0, 1, 10, 50, 250 mg/L）to detect the malondialdehyde（MDA）content and the activities of protective enzymes in their different organs. The results indicated that low potassium decreased the MDA content of all the organs except that of the leaves in the treatments K0, K1 and K10 and that of the roots in K10 and K50, but no significant difference in MDA content of all organs among all the treatments. Low potassium reduced the superoxide dismutase（SOD）activities in all the organs treated with potassium except in the leaves in K0, stem barks and roots in K50, and the SOD activities in the leaves decreased evidently; potassium shortage leaded to a decrease of peroxidase（POD）activities in all the organs except in the leaves in K1, K10 and K50 and in the roots in K1, but showed no obvious difference in POD activities among all the organs; low potassium significantly increased the leaf catalase（CAT）activities. Therefore, the protective enzymes in Hevea brasiliensis seedlings function synergistically in defense of potassium stress in all the organs of young rubber seedlings.