模拟霜冻条件对黄瓜幼苗生长及抗氧化酶活性的影响
Effects of simulated frost condition on growth and antioxidant enzyme activity of cucumber seedlings
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摘要: 目的分析防霜冻技术对模拟霜冻过程中黄瓜幼苗形态、抗氧化酶活性和细胞膜透性的影响,为黄瓜防霜冻技术推广应用提供技术支持.方法在模拟自然霜冻条件下对黄瓜幼苗进行防霜冻技术处理(TR),在降温处理后不同时期调查黄瓜幼苗的株高、茎粗、叶长和叶宽及统计冷害指数,并在温度降至10 ℃/5 ℃前1 d(-1 d)及下降至10℃/5℃后1、3和5 d测定其抗氧化酶活性等生理指标.结果在模拟自然霜冻条件下,降温处理后3 d TR组黄瓜幼苗的相对株高为106.00%,显著高于对照组(CK,95.50%)(P<0.05,下同),相对茎粗、相对叶长和相对叶宽与CK组无显著差异(P>0.05,下同);降温处理后5 d TR组的冷害指数为40.67%,显著低于CK组.降温处理-1 d,TR组黄瓜幼苗的超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性显著高于CK组,降温处理后1~3 d,SOD和CAT活性呈上升趋势,且高于CK组,但差异不显著;过氧化物酶(POD)活性在降温处理的-1~2 d高于CK组,在降温处理后3~5 d低于CK组,但差异均不显著;TR组与CK组的过氧化氢(H2O2)含量在降温处理的-1~5 d均呈上升趋势,TR组的H2O2含量低于CK组;TR组的丙二醛(MDA)含量在降温处理前后变化不明显,但在降温处理后1和5 d显著低于CK组.结论在霜冻来临前对黄瓜幼苗进行防霜冻技术处理,能有效提高其对霜冻的耐受性,显著减轻黄瓜冷害程度.Abstract: ObjectiveTo provide technical support for the application and popularization of frost-prevention for cu-cumber,the effects of frost-prevention technique on morphology,antioxidant enzyme activity and cell membrane permea-bility of cucumber seedlings were analyzed under simulated frost condition.MethodCucumber seedlings were treated with frost-prevention technique(TR)under simulated frost condition,and then plant height,stem diameter,leaf length, leaf width and index of chilling injury were investigated at different times after temperature drop treatment.Antioxidant enzyme activity and other physiological indexes were measured 1 d before temperature dropped to 10 ℃/5 ℃(-1 d)and 1,3,5 d after temperature dropped to 10 ℃/5 ℃.ResultUnder simulated natural frost conditions,the relative plant height of cucumber seedlings after 3 d of TR group was 106.00%,which was significantly higher than that of CK 95.50% (P<0.05,the same below).There was no significant difference in relative stem diameter,relative leaf length,and relative leaf between TR and CK(P>0.05,the same below).The chilling injury indexes of TR group was 40.67% after 5 d tempera-ture drop treatment,which was significantly lower than that of CK.Superoxide dismutase(SOD)and catalase(CAT)ac-tivities of cucumber seedlings were significantly higher than those of CK after TR group for-1 d.The activities of SOD and CAT showed an upward trend after 1-3 d of treatment and were higher than those of CK,but the difference was not significant.Peroxidase(POD)activity of TR during-1-2 d of treatment was higher than CK,and it was lower than CK 3-5 d after treatment,but the difference was not significant.The content of hydrogen peroxide(H2O2)in TR group and CK group increased during-1-5 d of temperature drop treatment.The content of H2O2was lower than that of CK after treat-ment.Malondialdehyde contents(MDA)of TR group did not change greatly before and after temperature drop treatment, but it was significantly lower than that of CK on day 1 and day 5 after treatment.ConclusionApplying frost-prevention technique before the frost can improve the tolerance of cucumber seedlings against frost,and reduce the chilling injury of cucumber seedlings.