Trxs过量表达对UV-B胁迫的大麦幼苗叶片抗氧化酶活性的影响

Effects of overexpressing Trxs on antioxidant enzymes activities in transgenic barley seedling leaves under ultraviolet B stress

以过量表达硫氧还蛋白s基因(Trxs)的转基因大麦(LSY-11-1-1,T)及其非转基因对照(LSY,CK)为材料,采用水培法研究了UV-B胁迫条件下转基因大麦幼苗(UVB-T)与对照(UVB-CK)叶片中Fv/Fm值、H2O2与MDA含量以及抗氧化酶活性的变化.结果表明,UV-B处理引起大麦幼苗叶片Fv/Fm值降低,H2O2和MDA含量升高,过氧化物歧化酶(SOD)、过氧化物酶(POD)、谷胱甘肽过氧化物酶(GSH-PX)与过氧化氢酶(CAT)等抗氧化酶活性出现不同程度的增加;UVB-T的Fv/Fm值极显著高于UVB-CK,而H2O2和MDA含量均极显著低于UVB-CK,同时,其上述抗氧化酶活性普遍高于UVB-CK,而且UVB-T的CAT活性变化趋势与UVB-CK明显不同,其CAT出现2次活性高峰,而UVB-CK仅出现1次.

The barley variety,LSY（CK）and its transgenic line overexpressing Trxs（LSY-11-1-1,T）were employed to measure the Fv/Fm value,contents of H2O2 and malonaldehyde（MDA）,and the antioxidant enzyme activity under ultraviolet B（UV-B） radiation stress with hydroponic method.The results showed that the Fv/Fm value in leaves of barley seedling treated with UV-B radiation was significantly lower than that in the samples untreated（P0.01）,and the content of H2O2 and MDA was significantly increased by UV-B radiation（P0.01）.Activities of superoxide dismutase（SOD）,guaiacol peroxidase（POD）,glutathione peroxides（GSH-PX） and catalase（CAT） give a rise to different degrees under the UV-B stress.In comparison with UVB-CK,the Fv/Fm value of UVB-T was significantly higher,but the content of H2O2 and MDA of UVB-T was significantly lower than UVB-CK（P0.01）.Activities of antioxidant enzymes given above in UVB-T leaves were generally higher than UVB-CK.Moreover,the activity change tendency of CAT in UVB-T and UVB-CK was different,as there are two activity peaks in the former,but only one in the latter.