甘薯长喙壳侵染对甘薯块根抗氧化酶活性的影响

摘要

以易感黑斑病甘薯品种"徐薯 18"为试验材料,分别接种分离自石榴、甘薯和芋头的甘薯长喙壳(Ceratocystis fimbriata),研究其保护酶活性及丙二醛(MDA)含量变化.结果显示,非亲和性菌株[分离自石榴的甘薯长喙壳(CQS2)和分离自芋头的甘薯长喙壳(YP1)]和亲和性菌株[分离自甘薯的甘薯长喙壳(sP1)]接种的甘薯块根苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性,与对照处理相比均有升高,且接种CQS2和YP1的处理始终高于接种SP1的处理;非亲和性菌株和亲和性菌株接种的甘薯块根MDA含量均呈先上升后下降趋势,且接种CQS2和YP1的处理在接种25 h时MDA含量明显高于接种SP1的处理,接种SP1的处理在接种后期(50 h)的MDA含量降至与对照相当水平.由此表明:不同寄主的甘薯长喙壳侵染甘薯块根后,非亲和性接种菌株(CQS2和YP1)比亲和性接种菌株(sP1)能增强POD、SOD和CAT酶活性及诱导较多的MDA,从而增强病原菌侵染的抗性.%Three strains of Ceratocystis fimbriata isolated from sweet potato (Ipomoea batatas), pomegranate (Punica granatum) and taro (Colocasia esculenta) were respectively inoculated on sweet potato to study the changes of protective enzyme activity and MDA content.Results showed that the activities of sweet potato PAL, POD, SOD and CAT increased after infection with both incompatible (taro strain, pomegranate strain) and compatible (sweet potato strain) strains.The effect was more significant for incompatible strains than compatible strains.When once infected by three trains, sweet potato MDA content increased first and then decreased.MDA content was higher at 25 h after infected incompatible strains than compatible strains.At late stage inoculation (50 h),sweet potato MDA content infected compatible strains dropped to lower levels close to control.Compared with compatible strains,incompatible strains improved POD, SOD and CAT activity and increased MDA content, which enhanced resistance against C.fimbriata infection.