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野生一粒小麦(Triticum boeoticum Boiss)、栽培小麦“扬麦五号”(T.aestivum L.)的旗叶自然衰老过程中,活性氧清除系统中各部分的清除能力下降是不均衡的。在光合速率高值持续期(叶绿素含量缓降期),SOD的活力略有下降,过氧化氢酶(CAT)活力却迅速下降,同时抗坏血酸过氧化物酶(ASP)活力呈现先上升后下降的趋势,上述SOD、CAT、ASP活力变化的不均衡,最终导致H_2O_2的迅速累积,从而使叶片迅速进入衰老(叶绿素含量速降期),于是SOD活力迅速下降。野生一粒小麦活性氧清除系统中各部分清除能力失衡过快,可能是其早衰的原因之一。H_2O_2的迅速累积与叶片衰老的启动密切相关。
During the natural senescence of the flag leaf of the wild wheat (Triticum boeoticum Boiss) and the cultivated wheat “Yangmai 5” (T.aestivum L.), the scavenging capacity of various parts of the active oxygen scavenging system is not balanced. During the period of high photosynthetic rate (chlorophyll content descending), the activity of SOD decreased slightly and the activity of catalase (CAT) decreased rapidly. At the same time, the activity of ascorbate peroxidase (ASP) increased first and then decreased As a result, the imbalanced changes in the activities of SOD, CAT and ASP above all led to the rapid accumulation of H 2 O 2, leading to rapid leaf senescence (rapid decline of chlorophyll content), and the rapid decline of SOD activity. One of the reasons for its premature aging may be one of the reasons for the unbalanced scavenging capacity of various parts of the wild one-wheat active oxygen scavenging system. The rapid accumulation of H 2 O 2 is closely related to the initiation of leaf senescence.