渗透胁迫对麻疯树幼苗生理生化特性的影响

Physiological and biochemical characteristics of Jatropha curcas seedlings under osmotic stress

为揭示干旱缺水对麻疯树Jatropha curcas幼苗生理生化特性的影响,通过设置不同质量分数的聚乙二醇(PEG6000)渗透胁迫,研究了胁迫处理下幼苗各项生理指标的消长变化规律,并进行相关分析。结果表明,随胁迫时间的延长,麻疯树幼苗叶片相对含水量在5%和10%处理时略微升高,在15%,20%和30%聚乙二醇(质量分数)处理时持续下降,至10d时分别下降了40.7%,46.0%和55.9%;可溶性蛋白质量分数、活性氧(O2·-)产生速率、保护酶系统超氧化物歧化酶、谷胱甘肽还原酶、过氧化氢酶活性和叶绿素质量分数在各种不同处理条件下先升高后下降。而丙二醛质量分数在各种不同处理条件下随胁迫时间的延长逐渐增加,至10d时在15%处理时增加最显著(P<0.01),与对照相比,上升了2.4倍。相关分析表明,相对含水量与丙二醛、超氧化物歧化酶活性和谷胱甘肽还原酶活性呈显著负相关(P<0.05);可溶性蛋白则与保护酶系活性及叶绿素呈显著正相关(P<0.05);O2·-产生速率、丙二醛分别与超氧化物歧化酶活性和谷胱甘肽还原酶活性呈极显著正相关(P<0.01);3种保护性酶活性之间及它们分别与叶绿素质量分数都呈极显著正相关(P<0.01)。综上所述,渗透胁迫对麻疯树幼苗的影响是多种生理生化过程综合作用的结果,幼苗通过诱导保护酶系提高抗旱性,具有较强的渗透胁迫忍受能力。

To reveal the effects of drought and water shortage on physiological and biochemical characteristics of Jatropha curcas seedlings,osmotic stress treatments（0,5%,10%,15%,20%,and 30% concentrations of PEG 6000） were applied.Also Duncan＇s multiple comparisons and a correlation analysis were carried out.Results showed that with prolonged stress（up to 10 d）,the leaf relative water contents（RWC） with the 15%,20%,and 30% osmotic treatments decreased significantly（P0.01）.For all treatments,soluble protein and chlorophyll,O2-production rate,and protective enzymes super-oxide dismutase（SOD）,glutathione reductase（GR）,and catalase（CAT） increased then decreased.Compared to the control,Malondialdehyde（MDA） content for the 15% osmotic treatment up to 10 d,significantly increased（P0.01）.A correlation analysis showed significant negative correlations between RWC and 1） MDA（r =-0.483,P 0.05）,2） SOD（r =-0.464,P0.05）,and 3） GR（r =-0.453,P0.05）;whereas significant positive（P0.05） correlations were found between soluble protein content and the protective enzyme activities and chlorophyll（chl） The O2-production rate and MDA were significantly and positively（P 0.01） correlated with SOD or GR activities;while the protective enzymes system activities had significant positive（P 0.01） correlations with chl.Thus,J.curcas seedlings resisted drought stress by increasing the protective enzyme activities which increased its tolerance to osmotic stress.