低温和UV-B复合胁迫对小麦幼苗抗氧化酶和渗透调节物质的影响

为揭示UV-B辐射与早春低温复合环境对小麦生理生化的影响,以小麦品种龙麦26为材料,分析了低温、UV-B及二者复合胁迫下小麦幼苗抗氧化酶活性和渗透调节物质含量。结果表明,与对照(正常生长条件)相比,低温下小麦丙二醛(MDA)和可溶性糖含量及过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、苯丙氨酸解氨酶(PAL)活性显著升高,过氧化物酶(POD)活性显著降低,原初光能转化效率(F_v/F_m)、脯氨酸含量未发生显著性变化;UV-B处理诱导MDA和脯氨酸含量及POD、PAL活性显著增加,但显著降低F_v/F_m和可溶性糖含量,CAT和SOD活性没有发生显著的变化;低温和UV-B复合处理后SOD和PAL活性显著增加,而F_v/F_m、CAT和POD活性及可溶性糖含量显著下降,MDA和脯氨酸含量却没有显著变化。以上结果说明,小麦幼苗不同代谢生理指标对低温、UV-B及二者复合胁迫响应程度和方式不同。

Effect of Low Temperature and UV-B on the Antioxidant Enzymes and Osmotic Substances in Wheat Seedlings

To clearify the effects of environmental stresses(the enhanced UV-B and low temperature and both combined stress) on the physiological and biochemical indexes of wheat seedling,the antioxidant enzymes and osmotic metabolites in wheats seedlings were investigated in this study.Compared with the control,under the low temperature,the content of MDA and soluble sugar,and the activity of CAT,SOD and PAL in wheat seedlings were increased apparently,while the activity of POD was decreased significantly,and PSⅡ and proline content changed a little.Under the enhanced UV-B,the content of MDA and proline,and the activity of POD and PAL in wheat seedlings were increased remarkably.The Fv/Fm and the content of soluble sugar were decreased significantly,and the CAT and SOD showed no difference.Under the combined stress,the activity of SOD and PAL were increased significantly,and Fv/Fm,the activity of CAT and POD,and the content of soluble sugar were decreased significantly,and the content of MDA and Proline remained relatively stable.All the results showed that the physiological indices of wheat seedlings responded to low temperature,UV-B and the combined stress in different pathways.