连续多代UV-B照射对麦长管蚜保护酶活性的影响

Effects of UV-B radiation in successive generations on the activities of protective enzymes in the grain aphid,Sitobion avenae( Hemiptera:Aphididae)

【目的】为探明中波紫外线(UV-B)连续多代处理对麦长管蚜Sitobion avenae(Fabricius)的作用机制,发现在UV-B环境压力下害虫进化动力。【方法】用强度为0.25 W/m2的UV-B对每代麦长管蚜进行6 h照射,以处理后成蚜当天产的仔蚜为继代饲养材料,连续饲养18代,提取第1,4,8,12,15和18代的对照组和处理组无翅孤雌成蚜的保护酶液,利用分光光度计测定其超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)3种保护酶活性。【结果】不同世代的对照组间3种保护酶活性均无差异(P>0.05),处理组间有显著差异(P<0.05)。随着UV-B胁迫世代增加,SOD活性呈先升高后下降的趋势,活性高峰出现在第15代。POD活性呈下降趋势,处理组活性均高于对照组,且在第1和4代处理组与对照组间差异极显著(P<0.01)。CAT活性先下降后升高,在第8,12和15代处理组与对照组间无显著差异(P>0.05),而至第18代处理组与对照组间差异又恢复为极显著(P<0.01)。【结论】麦长管蚜受到短期UV-B胁迫时,其体内SOD,POD和CAT 3种保护酶活性均升高,以抵御UV-B胁迫引起的自由基伤害;而经过到长期UV-B胁迫后,主要依靠SOD和CAT 2种保护酶清除活性氧自由基。

【Aim】To understand the action mechanisms of ultraviolet B（ UV-B） radiation in successive generations on the change of protective enzyme activities in the grain aphid,Sitobion avenae（ Fabricius）and to find the drive on insect evolution under the pressure of UV-B environment. 【Methods】In this study,we used 0. 25 W /m2 of UV-B to radiate each generation of S. avenae for 6 h,and then continuously reared the nymphs for 18 generations. We chose the 1st,4th,8th,12 th,15th,18 th generations of wingless and parthenogenetic adults in both the treatment group and control group,and used spectrophotometry to measure the activities of three protective enzymes（ superoxide dismutase,SOD; peroxidase,POD; catalase,CAT） in them. 【Results】The activities of SOD,CAT and POD in the control groups of different generations had no significant difference（ P 〉 0. 05）,while those in the treatment groups of different generations had significant difference（ P 〈 0. 05）. With the increase of the generations under UV-B radiation,the SOD activity first rose and then declined,reaching the peak in the 15 th generation. The POD activity showed a declining trend with the increase of the generations under UV-B radiation but kept higher than that in the control group,and only in the 1st and 4th generations were there significant differences in the POD activity between the treatment group and the control group.The CAT activity first fell and subsequently increased with the increase of the generations under UV-B radiation,and those in the 8th,12 th and 15 th generations under UV-B radiation showed no significant difference with the control group（ P 〈 0. 05）,but the CAT activity in the 18 th generation under UV-B radiation showed extremely significant difference with that of the control group（ P 〈 0. 01）.【Conclusion】When S. avenae is irradiated by UV-B for a short time,the activities of protective enzymes in the body rise to resist the damage of radicals. As UV-B radiation works longer,the POD activity tends to be stable,while the SOD and CAT activities are significantly higher than the normal level to protect against UV-B stress.