冷锻炼和ABA诱导水稻幼苗提高抗冷性期间膜保护系统的变化

冷锻炼和ＡＢＡ处理提高了水稻幼苗叶绿体ＳＯＤ和ＧＲ活性及叶片抗氧化剂ＡｓＡ和ＧＳＨ的含量，降低了膜电解质泄漏，增强了幼苗的抗冷性．等电聚焦电泳分析表明，冷锻炼和ＡＢＡ处理苗叶绿体ＳＯＤ三条同工酶带和ＧＲ１、２、３和６同工酶带都有不同程度的增强．低温胁迫后，处理和未处理首的ＳＯＤ、ＧＲ活性和ＡＳＡ、ＧＳＨ含量均有所下降．但处理苗的水平仍维持在未处理苗之上．亚胺环已酮可抑制因冷锻炼和ＡＢＡ诱导增加的ＳＯＤ和ＧＲ活性，并使叶片电解质泄漏增大．本试验结果表明冷锻炼或ＡＢＡ诱导水稻幼苗抗冷性提高时，对防御活性氧的保护系统有类似的影响。

CHANGE OF THE MEMBRANE PROTECTIVE SYSTEM DURING THE ENHANCEMENT OF CHILLING RESISTANCE INDUCED BY COLD HARDENING AND ABA TREATMENT IN RICE SEEDLINGS

The changes of the protective system against activated oxygen during the enhancement of the chilling resistance induced by the cold hardening and ABA treatment in rice seedlings were studied. The results indicated that in the treated seedlings, activities of SOD and GR of the chloroplast as well as the antioxidant AsA and GSH contents of the leaves increased while the electrolyte leakage decreased. Therefore, its chilling resistance Was enhanced.By using isoelectrofocusing gel electrophoresis analysis, the intensity of three isozyme bands of SOD and the isozyme bands 1, 2, 3 and 6 of GR, except 4, 5, were increased to a different degree in two treated seedlings.After chilling stress, all the activities of SOD, GR and the contens of AsA, GSH were decreased in the treated and untreated seedlings, but the reduction of two enzyme activities and the antioxidant contents in the treated seedlings were less than those of the untreated seedlings.The increase of SOD and GR activities induced by cold hardening and ABA treatment were inhibited by cycloheximide (CHM), at the same time the electrolyte leakage was increased. These results showed that there was a close correlation between the enhacement of chilling resistance and the increase of the protective system ability in the rice seedlings and that the effects of cold hardening and ABA treatment on the Protective system against activated oxygen in rice seedlings were similar.