干旱胁迫对小麦幼苗抗氰呼吸和活性氧代谢的影响

研究了干旱胁迫对抗旱性强弱不同的两种小麦幼苗的抗氰呼吸和活性氧代谢的影响。干旱胁迫导致了两种小麦抗氰呼吸活性及基因转录水平的下降，但抗旱品种在轻度干旱胁迫下表现出一定的适应能力，其抗氰呼吸活性及基因转录水平均高于不抗旱品种。干旱胁迫下，对干旱敏感的小麦幼苗叶片中活性氧含量高于抗旱小麦；3种抗氧化酶的活性低于抗旱小麦的3种抗氧化酶的活性。据此认为，严重的干旱胁迫引起活性氧含量的增加扰动了活性氧与抗氰呼吸之间的应答平衡，但抗氰呼吸可能通过清除活性氧等机制而起了抗旱的作用。

Effects of Drought Stress on Cyanide-resistant Respiration and Metabolism of Reactive Oxygen in Wheat Seedling

The changes in cyanide-resistant respiration and metabolism of active oxygen species in drought-sensitive and drought-resistant wheat seedlings under water stress were studied. In general, drought stress decreased the level of cyanide-resistant respiration and AOX1 mRNA content in wheat seedling leaves. But the drought-resistant cultivars, which had much higher level of cyanide-resistant respiration and AOX1 mRNA content than the drought-sensitive ones, presented an ability to adapt to mild drought stress. Under drought stress, the drought-sensitive wheat seedling leaves had higher O(-.)(2) and H(2)O(2) contents, but lower SOD, POX and CAT activities than drought-resistant cultivars. We guessed that severe drought stress could break down the balance between active oxygen species and cyanide-resistant respiration. However, cyanide-resistant respiration still could participate in the drought-resistance by lowering the level of active oxygen species besides by other mechanism.