1959～1988年间在安大略省种植的玉米杂交种籽粒产量的遗传改良,部分的归因于杂交种对环境胁迫耐力的提高。虽然植物对胁迫耐力的性质还没有被充分阐明,已认为氧自由基在植物逆境伤害和植物衰老中起着重要作用(Leshem,1988;Babbs等,1990)。叶绿体中光合作用的途径含有电子传递体,具有产生 The genetic improvement of grain yield in maize hybrids planted in Ontario between 1959 and 1988 was attributed in part to the increased tolerance of the hybrids to environmental stress. Although the nature of stress tolerance in plants has not been fully elucidated, oxygen free radicals have been found to play an important role in plant stress damage and plant senescence (Leshem, 1988; Babbs et al., 1990). The photosynthetic pathway in chloroplasts contains an electron mediator that has the ability to produce