干旱胁迫对光果甘草幼苗根系MDA含量及保护酶POD、CAT活性的影响

Effect of drought stress on the content of malondialdehyole and activity of cell defense enzymes in Glycyrrhiza glabra seedlings roots

实验室用甘露醇模拟不同程度干旱胁迫,观测光果甘草幼苗根系膜脂过氧化水平受影响的情况。结果表明当干旱胁迫程度由-0.5 MPa上升到-1.0 MPa时,甘草根系MDA的含量随干旱胁迫程度的增强而升高,同时甘草幼苗根系POD活性下降,而CAT的活性则呈现升高趋势。说明干旱胁迫程度由轻度转为中度后,甘草幼苗的根系产生了膜脂过氧化作用。POD与CAT这两种保护酶活性也随之产生变化,POD活性先升后降,而CAT活性则持续上升,二者相互配合协同作用,以维持和保护甘草幼苗根系细胞膜的完整性,降低膜脂过氧化水平。

Glycyrrhiza glabra seedlings were treated with the osmotic stress .solution mannitol （ -0.5 MPa, 1.0MPa）. The content of MDA and two defense enzymes activities （POD, CAT） in Glycyrrhiza glabra seedlings roots were measured at the fifth day after treatment. The content of MDA increased at - 0.5 MPa and - 1.0 MPa rnannitol stress, the increase rate was higher at - 1.0 MPa stress than that at 0.5 MPa stress, POD activity increased at - 0.5 MPa.stress and declined at - 1.0 MPa stress, CAT activities raised with the stress level. This result suggested that the two defense enzymes POD and CAT might play a key role in reducing lipid peroxidation under drought strew.