干旱胁迫对沙枣幼苗根茎叶保护酶系统的影响

在不同浓度PEG-6000溶液模拟的干旱胁迫条件下,对沙枣根茎叶中的SOD、CAT和POD 3种保护酶和丙二醛进行研究,结果表明:(1)随着干旱胁迫的加剧,沙枣叶中SOD酶活性和CAT酶活性均呈现上升趋势,但POD酶活性却先上升后下降;(2)沙枣茎中SOD酶活性在轻度胁迫下高于CK,中度和重度胁迫下却低于CK,POD酶活性和CAT酶活性却随着干旱胁迫的增加呈增加趋势,这说明虽然在中度和重度胁迫下,SOD酶活性有所下降,POD酶和CAT两种酶清除SOD转化的H2O2的能力还在增强;(3)随着干旱胁迫的加剧,沙枣根中SOD酶活性在轻度胁迫下高于CK,中度和重度胁迫下和CK差异不显著, 各干旱胁迫下POD酶活性均显著高于CK,但各干旱胁迫之间差异不显著, CAT酶活性先升高后下降,但仍高于CK;(4)轻度干旱胁迫下,沙枣根茎叶中膜质过氧化程度均较低,和CK差异不显著;中度胁迫下,沙枣根茎中膜质过氧化程度增高(茎>根),但重度干旱胁迫下,沙枣根茎叶中膜质过氧化程度均明显增高(叶>茎>根).

The Effect of Drought Stress on Protective Enzymes System in Roots, Stems and Leaves of Elaeagnus angustifolia L. Seedlings

Under different concentrations of PEG -6000 solution simulated drought stress conditions, protective enzymes and malondialdehyde ( MDA) of Elaeagnus angustifolia L. In leaves, stems and roots were studied, the results showed: (1) Along with the increasing degree of drought stress, activity of superoxide dis-mutase(SOD) ,catalase(CAT) in leaves always increased,activity of perocidase(POD) first decreased , then increased; (2) Under light drought stress, activity of SOD in stems was higher than that of the control, activity of SOD under moderate stress and severe stress in stems was lower than that of the control, activity of POD and CAT always increased,which showed that activity of SOD decreased under moderate and severe stress,but the capacity of POD and CAT to remove into H_2O_2 was increasing; (3) Along with the increasing degree of drought stress,activity of SOD in roots was higher than that of the control, activity of SOD in roots was not different significantly with that of the control under moderate stress and severe stress, activity of POD was significantly higher than that of the control under different drought stress, but the difference between drought stress was not significant, activity of CAT first decreased, then increased, which was still higher than that of the control; (4) Under light drought stress, membrane lipid pera.idation of leaves,stems,roots of Elaeagnus angustifolia was lower, which was not significantly different from that of the control, and membrane lipid peroxidation of stems, roots increased (stem > root) under moderate drought stress, membrane lipid peroxidation of leaves, stems, roots was significantly increased (leaf >stem > root) under severe drought stress.