根系分泌物在有机氯农药残留降解过程中的作用  

The role of root exudates in degradation of OCPs in rhizosphere soils

作　　者：潘声旺[1] 雷志华[1,2] 吴云霄[1,3] 杨丽娟[1] 何茂萍[1] 曹生宪[1] 

机构地区：[1]成都大学建筑与土木工程学院,四川成都610106 [2]信阳职业技术学院检验技术学院,河南信阳464000 [3]延安大学生命科学学院,陕西延安716000

出　　处：《云南大学学报（自然科学版）》2017年第4期669-676,共8页Journal of Yunnan University(Natural Sciences Edition)

基　　金：国家自然科学基金(31300439);四川省教育厅自然科学研究基金(17ZA0091);成都市科技惠民计划(2015-HM01-00368-SF)

摘　　要：为了探讨根系分泌物在植物修复持久性有机污染物过程中的作用,借助盆栽模拟实验,研究了苏丹草(Sorghum sudanense)的根系分泌物对土壤中有机氯农药(organochlorine pesticides,OCPs)残留的降解效应以及对根际微生物群落结构的影响.结果显示,供试质量比(0~336.48 mg·kg^(-1))范围内,根系分泌物促进了"根际"土壤(TR_2)中OCPs的去除.添加30 mL总有机碳质量浓度为246 mg·L^(-1)根系分泌物浓缩液修复平衡20 d后,"根际"土壤(TR_2)中OCPs去除率高达79.21%(69.23%~86.49%),比对照组(CK)高出36.43%,比微生物活性被抑制的TR_1组高出52.28%;相同污染水平下,"根际"土壤(TR_2)中土壤微生物碳也明显高于CK、TR_1组.实验期间,细菌的磷脂脂肪酸在OCPs污染土壤中占主导地位,其次为真菌,它们的群落动态与OCPs降解速率的变化趋势相一致.说明OCPs降解过程中,根系分泌物通过改变根际土壤中细菌、真菌的种群数量及其群落结构所营造的根际微生态环境,是促进OCPs降解的关键因素.To investigate the effect of root exudates of Sudan grass （ Sorghum sudanense） on OCPs dissipation, pot experiments were carried out by simulating a gradually decreasing concentration of root exudates with the distance away from root surface in rhizosphere. The influence of root exudates on the degradation of organochlorine pesticides （OCPs） in soils was determined,microbial ecological characteristics in OCPs-contaminated soils were evaluated.The results showed that Sudan grass root exudates stimulated OCPs degradation significantly at their initial concentrations ranging from 0 to 336.48 mg·kg^-1 after 20 days of simulating phytoremediation. Among all treatments,the degradation rate in the root exudates-soil system （TR2） was of the highest,79.21% of OCPs were removed from the soils averagely and was 36.43% higher than that of CK （e.g., spiked soil）, and 52.28% higher than that of TR1（ e.g., spiked soil with addition of 0.05% NaN3 ） while 30 mL exudates with 246 mgTOC ·L^-1 was added.Soil microbial biomass carbon in the root exudates-soil system was also of the highest and there was close relation between OCPs degradation and soil microbes during the whole experiments.In the test soils which phospholipid fatty acids were probed and analyzed by the means of GC-MS, the microbial community was dominated by bacteria, and followed by fungi, and the variation trend was consistent with different OCPs degradation levels,which indicated that the OCPs was degraded mainly by bacteria, and the effect of root exudates on OCPs degradation was mainly carried out through the effects on bacteria and fungi population.Thus,the root exudates of Sudan grass might change microbial ecological characteristics in the process of phytoremediation by promoting the rhizosphere microbial growth and modifying the community structure, and are the key regulators in rhizosphere communication which can modify the biological and physical interactions between roots and soil organisms, and then enhance the degradation of OCPs in

关 键 词：有机氯农药 苏丹草 根系分泌物 土壤微生物 根际效应 

分 类 号：X131.3[环境科学与工程—环境科学]