磺胺类抗生素对根际微域土壤酶活性的影响

Effects of sulfonamides(SAs)on rhizosphere soil enzyme activities

通过多隔层根际箱培养实验研究了磺胺类抗生素磺胺甲恶唑(SMZ)和磺胺甲基嘧啶(SM1)对油菜种植土壤不同根际微域的土壤脱氢酶(DHA)和过氧化氢酶(CAT)的影响。结果显示,SMZ胁迫下,低浓度处理组促进了根际及近根际区的DHA活性,而高浓度处理组则抑制了其DHA活性。同时,各浓度处理组均抑制了主体土壤区及近主体土壤区中DHA的活性。各浓度处理组均诱导了根际及近根际区的CAT活性,却抑制了主体及近主体区的CAT的活性。SM1胁迫下,各浓度处理组均诱导了近根际区的DHA活性,却抑制了根际区及主体土壤区及近主体土壤区中的DHA活性,而各浓度处理组几乎均诱导了各分区的CAT活性。同时,随着SMZ染毒浓度增加,两种酶活性均降低,而随着SM1染毒浓度增加,DHA活性升高,CAT活性降低。两种土壤酶对两种磺胺类抗生素的响应不同,但整体上均为近根际区的响应值较高,其次才是根际区,然后为近主体土壤区和主体土壤区,并不是简单的随距离增加呈递减效应。

The effects of sulfonamides sulfamethoxazole(SMZ),and sulfamerazine(SM1)on the activities of dehydrogenase(DHA)and catalase(CAT)in the rhizosphere of rape were investigated through rhizobox culture experiments.The results indicated that the stress of low SMZ concentration promoted the DHA activities,while the high SMZ concentration treatments inhibited them in rhizosphere and near rhizosphere zones.The occurrence of low and high concentrations of SMZ inhibited the activities of DHA in bulk and near bulk soil zones.The CAT activities in rhizosphere and near rhizosphere zones were promoted by the stress of low and high SMZ concentration treatments.However,the CAT activities in bulk and near bulk soil zones were inhibited by both SMZ concentration treatments.The stress of low and high concentrations of SM1 enhanced the activities of DHA in near rhizosphere zones.However,the occurrence of SM1 inhibited the DHA activities in rhizosphere,bulk and near bulk soil zones.The stress of low and high concentrations of SM1 promoted the activities of CAT in almost all the soil zones.Though the responses of DHA and CAT to SMZ and SM1 were different,the soil enzymes in near rhizosphere zones were higher,then rhizosphere zones,and then near bulk and bulk soil zones.They were not simplely decreased with distance.