干旱胁迫对冷蒿保护酶活性及膜脂过氧化作用的影响

Membrane lipid peroxidation and protective enzyme systems with drought stressed Artemisia frigida leaves

为了探讨冷蒿Artemisia frigida对干旱胁迫的适应机制,以盆栽天然草场冷蒿为材料,采用自然干旱胁迫处理测定了冷蒿叶片和土壤相对含水量,叶片膜透性和丙二醛(MDA)质量摩尔浓度以及保护酶活性。结果表明:在干旱胁迫初期(0～8d,土壤含水量大于6.5%),冷蒿叶片失水较少,超氧化物歧化酶(SOD)活性表现出先升高后降低的变化趋势,过氧化氢酶(CAT)活性表现出先降低后升高的变化趋势,丙二醛保持在稳定水平,膜系统受到的伤害较小;随着干旱胁迫时间和程度的加强,超氧化物歧化酶、过氧化氢酶和过氧化物酶(POD)酶活性都有不同程度的降低,丙二醛开始大量积累,膜系统受到严重伤害;至第12天,土壤含水量下降至2.7%,冷蒿叶片全部永久性萎蔫。在干旱胁迫下超氧化物歧化酶和过氧化氢酶在活性氧清除过程中起着重要作用。

In order to explore adaptive mechanisms of Artemisia frigida in an arid grassland,water content,cell membrane permeability,malondialdehyde（MDA） content,and protective enzyme activities for a pot culture were studied using natural arid processing with soil relative water content being determined. Results showed that the leaves of A. frigida had low water loss,superoxide dismutase （SOD） activity first increased and then decreased,catalase （CAT） activity first decreased and later increased,MDA content was steady,and in the early stage of drought stress （0-8 d after not wartering,with soil water content 6.5%） membrane system damage was slight. With increasing time and drought stress,SOD,CAT,and peroxidase （POD） activity decreased,MDA increased,and membrane systems were seriously hurt. To the twelfth day with soil water content being 2.7%,all leaves permanently wilted. Thus,with drought stress,SOD and CAT played an important role in cleansing reactive oxygen.