干旱胁迫对甘草幼苗活性氧代谢的影响

Effects of Drought Stress on Active Oxygen Metabolism in Glycyrrhiza uralensis Seedlings

以当年生甘草幼苗为试验材料,通过人工控制水分模拟干旱的处理方法,研究干旱胁迫对甘草根、叶组织中活性氧代谢的影响。结果显示,干旱处理后4d和6d,甘草根、叶组织中活性氧分别出现小幅积累,随之抗氧化酶类超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸氧化酶(APX)活性开始大幅提高,并一直维持高活性至处理后10～12d;随着胁迫时间的延长(处理后12～14d),抗氧化酶类活性迅速下降,与此相对应,活性氧再次出现大量积累,膜透性明显增加。以上结果表明,适度水分胁迫下,甘草自身通过抗氧化酶类活性提高及时清除活性氧,减轻膜损伤;重度胁迫下,上述活性氧代谢平衡破坏,活性氧积累,膜脂过氧化加剧。

The effects of antioxidant capacity in the formation of the drought-resistance were studied with one year old seedlings of Glycyrrhiza uralensis,which were treated with the method of artificially simulated drought stresses.The effects of drought stress on active oxygen metabolism in G.uralensis seedlings roots and leaves were studied.The results indicated that on the 4d and 6d,there were slightly accumulations of active oxygen enzymes in roots and leaves separately.And activities of superoxide dismutase（SOD）,peroxidase（POD）,catalase（CAT） and ascorbic acid oxidase（APX） increased obviously in the period of 10～12d.During 12～14d,activities of antioxidant enzyme decreased immediately,meanwhile active oxygen enzymes accumulated again,membrane lipid peroxidation increased immediately with it.The research showed that under moderate water stress,G.uralensis increased the antioxidant enzymes activities to clear active oxygen for reducing membrane injury;Under heavy stress,the active oxygen metabolism balance was damaged,active oxygen was accumulated,membrane lipid peroxidation was intensified.