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通过沙基培养方法研究不同浓度锌(Zn)对汞(Hg)胁迫下小麦幼苗叶绿素相对含量(SPAD)、丙二醛(MDA)与脯氨酸的积累及抗氧化酶活性等的影响.结果表明:单独Hg(10 mg L-1)胁迫下,小麦幼苗叶绿素含量降低,超氧化物歧化酶(SOD)与过氧化氢酶(CAT)活性受到抑制,MDA与脯氨酸含量升高.加入10 mg L-1Zn后,叶绿素含量比Hg单独胁迫升高了5.6%,MDA含量降低了32.4%,表明该浓度Zn在一定程度上缓解了Hg对小麦幼苗的毒害;Zn浓度高于10 mg L-1的处理中,叶绿素含量逐渐降低,MDA则呈升高趋势,表明随Zn浓度升高,Zn对Hg毒害的缓解作用逐渐降低.低浓度Zn(10~20 mg L-1)提高了Hg胁迫下小麦幼苗SOD与CAT活性,其活性随Zn浓度升高逐渐增加,20mg L-1Zn处理下,两种酶活性比Hg单独胁迫分别升高了103.3%与71.0%,高浓度Zn(50~100 mg L-1)处理下,两种酶活性则呈下降趋势,表明Zn对Hg胁迫下两种酶活性的促进作用逐渐减弱.在试验设置的Zn浓度范围内,脯氨酸含量均低于Hg单独胁迫,并且低于对照,说明外加Zn抑制了脯氨酸的生成.综上所述,10~20 mg L-1的Zn可以在一定程度上缓解10 mg L-1Hg对小麦幼苗造成的毒害.
The effects of different concentrations of zinc (Zn) on chlorophyll content (SPAD), malondialdehyde (MDA) and proline accumulation and antioxidant enzyme activities of wheat seedlings under mercury stress were studied by sand culture method.Results The results showed that the chlorophyll content, the activities of superoxide dismutase (SOD) and catalase (CAT) in wheat seedling were inhibited and MDA and proline contents were increased under the stress of 10 mg L-1 Hg alone Chlorophyll content increased by 5.6% and MDA content decreased by 32.4% compared with Hg alone under the stress of 10 mg L-1Zn, respectively. This indicated that Zn could alleviate the toxicity of Hg to wheat seedlings to a certain extent. Zn concentration was higher than 10 mg L -1, the content of chlorophyll decreased gradually and the content of MDA increased, which indicated that the alleviation effect of Zn on Hg poisoning gradually decreased with the increase of Zn concentration.High dose of Zn (10-20 mg L-1) Under 20mg L-1Zn treatment, the activities of SOD and CAT of wheat seedlings increased by 103.3% and 71.0% respectively compared with those under Hg stress alone. High concentrations of Zn (50 ~ 100 mg L-1), the activities of the two enzymes showed a decreasing trend, indicating that the promotion effect of Zn on the activity of the two enzymes gradually weakened under the Hg stress. In Zn concentration range, the content of proline was lower than that of Hg alone and lower than the control, indicating that addition of Zn inhibited the proline production.In summary, 10 ~ 20 mg L-1 Zn could be To some extent, alleviate the toxicity of 10 mg L-1Hg to wheat seedlings.