【摘要】 以郑州9023为供试材料,采用室内水培方法,研究了不同浓度Zn2(+0、30、60、120、240、360mg·L-1)对小麦幼苗生理活性的影响,初步阐明了Zn2+对小麦幼苗的毒害机理。结果表明,在Zn2+胁迫下,随处理浓度的升高,小麦幼苗叶片中超氧阴离子自由基(O·2-)含量、丙二醛(MDA)含量、可溶性糖含量、抗坏血酸过氧化物酶(APX)及过氧化物酶(POD)活性均呈上升趋势,超氧化物歧化酶(SOD)活性呈先下降后上升的趋势;抗坏血酸(ASA)含量、过氧化氢酶(CAT)活性均呈现先上升后下降的趋势,可溶性蛋白和叶绿素含量呈下降趋势。对SOD、POD、CAT同工酶的聚丙烯酰胺凝胶电泳结果分析表明,正常情况下,小麦幼苗叶片主要表达Rf值(相对迁移率)分别为0.98、0.96、0.9、0.8、0.6、0.48的6条SOD同工酶带;POD同工酶带主要分为5区,至少包括10条同工酶酶带;CAT主要表达2条同工酶带。浓度小于120mg·L-1的Zn2+抑制SOD同工酶的表达,促进CAT同工酶的表达,浓度大于240mg·L-1的Zn2+促进SOD同工酶的表达,抑制CAT同工酶的表达,Zn2+诱导小麦幼苗中POD同工酶的表达。Zn2+没有诱导新的CAT、SOD和POD同工酶的表达。更多还原

【Abstract】 Effects of different concentrations of Zn2+(0,30,60,120,240,360 mg·L-1)on the physiological activity in wheat seedling of Zhengzhou-9023 were investigated in order to elucidate the toxicity of zinc in the early developmental stage.Different physiological index had different responses to zinc.With increasing concentrations of Zn2+,the content of O2·-,MDA and soluble sugar,APX and POD activity all increased gradually.The average O2·-and MDA content at any other concentrations had significant difference compared to that of controls.No significant difference in soluble sugar content was found between under low concentrations of Zn2+(0~60 mg·L-1)and that of controls.APX activity at Zn2+ 360 mg·L-1 showed a significant difference compared with that of controls.POD activity was correlated with the concentrations of Zn2+(r2=0.942),but no significant difference was observed among different concentrations.SOD activity decreased when the concentrations of Zn2+ was lower than 120 mg·L-1,and then increased,and at 360 mg·L-1,no significant difference existed compared to that of controls.ASA content decreased when the concentration was lower than 120 mg·L-1,and then increased.But ASA content was not correlated with the concentrations of Zn2+.CAT activity increased with the increase of Zn2+,but decreased when the concentration was higher than 60 mg·L-1.CAT activity at 360 mg·L-1 Zn2+ had significant difference compared with that of controls.Content of soluble protein and chlorophyll decreased with increasing concentrations of Zn2+,and compared to that of controls,soluble protein significantly decreased at 360 mg·L-1 Zn2+.Content of chlorophyll was correlated with the concentrations of Zn2+(r2=0.975).By polyacrylamide gel electrophoresis(PAGE),Zn2+ induced the expression of POD isoenzymes of wheat seedling.When the concentration of Zn2+ was lower than 120 mg·L-1,Zn2+ induced the expression of CAT isoenzymes but inhabited the expression of SOD isoenzymes in wheat seedling.However,when the concentration of Zn2+ was more than 240 mg·L-1,Zn2+ inhabited the expression of CAT isoenzymes but induced the expression of SOD isoenzymes in wheat seedling.Zn2+ didn’t induce the expression of new CAT,SOD and POD isoenzymes.更多还原