根系分泌物在有机氯农药残留降解过程中的作用
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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( TR_2) 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 TR_1(e.g.,spiked soil with addition of 0.05% NaN_3) while 30 mL exudates with 246 mg TOC·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 soils.
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( TR_2) 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 TR_1(e.g.,spiked soil with addition of 0.05% NaN_3) while 30 mL exudates with 246 mg TOC·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 soils.
引文
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[14]LUO L,ZHANG S Z,SHAN X Q,et al.Oxalate and root exudates enhance the desorption of p,p'-DDT from soils[J].Chemosphere,2006,63(8):1 273-1 279.
[15]KIRK J L,KLIRONOMOS J N,LEE H,et al.The effects of perennial ryegrass and alfalfa on microbial abundance and diversity in petroleum contaminated soil[J].Environmental Pollution,2005,133(3):455-465.
[16]潘声旺,刘灿,黄方玉.根系分泌物对土壤中有机氯农药降解的强化效应及其作用机制[J].成都大学学报:自然科学版,2016,35(2):196-200.PAN S W,LIU C,HUANG F Y.Effects of ryegrass root exudates on degradation of organochlorine pesticides in soils and their enhancing mechanisms[J].Journal of Chengdu University:Natural Sciences Edition,2016,35(2):196-200.
[17]袁馨,魏世强,潘声旺.苏丹草对土壤中菲芘的修复作用[J].农业环境科学学报,2009,28(7):1 410-1 415.YUAN X,WEI S Q,PAN S W.The remediation of phenanthrene and pyrene in soil by Sudan grass(Sorghum vulgare L)[J].Journal of Agro-Environment Science,2009,28(7):1 410-1 415.
[18]潘声旺,袁馨,刘灿,等.苯并[α]芘对不同修复潜力羊茅属植物的根系分泌物中几种低分子量有机物的影响[J].植物生态学报,2016,40(6):604-614.PAN S W,YUAN X,LIU C,et al.Effects of benzo[α]pyrene on the organic compounds of low molecule weight excreted by root systems in five Festuca species with different remediation potentials[J].Chinese Journal of Plant Ecology,2016,40(6):604-614.
[19]谢晓梅,廖敏,杨静.黑麦草根系分泌物剂量对污染土壤芘降解和土壤微生物的影响[J].应用生态学报,2011,22(10):2 718-2 724.XIE X M,LIAO M,YANG J.Effects of ryegrass(Lolium perenne)root exudates dose on pyrene degradation and soil microbes in pyrene-contaminated soil[J].Chinese Journal of Applied Ecology,2011,22(10):2 718-2 724.
[20]PAN S W,WEI S Q,YUAN X,et al.The removal and remediation of phenanthrene and pyrene in soil by mixed cropping of alfalfa and rape[J].Agricultural Sciences in China,2008,7(11):1 355-1 364.
[21]李振高,骆永明,腾应.土壤与环境微生物研究法[M].北京:科学出版社,2008.LI Z G,LUO Y M,TENG Y.Methodology of soil environmental microorganism[M].Beijing:China Science Press,2008.
[22]马琨,杨桂丽,马玲,等.间作栽培对连作马铃薯根际土壤微生物群落的影响[J].生态学报,2016,36(10):2 987-2 995.MA K,YANG G L,MA L,et al.Effects of intercropping on soil microbial communities after long-term potato monoculture[J].Acta Ecologica Sinica,2016,36(10):2 987-2 995.
[23]HUANG W,WEBER W J.A distributed reactivity model for sorption by soils and sediments.10:relationships between sorption,hysteresis and the chemical characteristics of organic domains[J].Environmental Science and Technology,1997,31(9):2 562-2 569.
[24]WANG X,SATO T,XING B.Sorption and displacement of pyrene in soils and sediments[J].Environmental Science and Technology,2005,39(22):8 712-8 718.
[25]BEHERA N,SAHANI U.Soil microbial biomass and activity in response to Eucalyptus plantation and natural regeneration on tropical soil[J].Forest Ecology and Management,2003,174(1):1-11.
[26]ISAM H,DOMSCH K H.Relationship between soil organic carbon and microbial biomass on chronosequencse of reclamation sites[J].Microbial Ecology,1988,15(2):177-188.
[27]SHARMA P,RAINA V,KUMARI R,et al.Haloalkane dehalogenase Lin B is responsible forβ-andδ-hexachlorocyclohexane transformation in Sphingobium indicum B90A[J].Applied and Environmental Microbiology,2006,72(9):5 720-5 727.
[28]JAGNOW G,HAIDER K,ELLWARDT P C.Anaerobic dechlorination and degradation of hexachlorocyclohexane isomers by anaerobic and facultative anaerobic bacteria[J].Archives of Microbiology,1977,115(3):285-292.
[29]ADI S P,ICHIRO K,RYUICHIRO K.Degradation of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane(DDT)by brown-rot fungi[J].Journal of Bioscience and Bioengineering,2008,105(6):614-621.
[2]潘声旺,吴云霄,罗竟红,等.成都城区蔬菜地土壤中农药残留及其分布特征[J].生态环境学报,2011,20(3):538-543.PAN S W,WU Y X,LUO J H,et al.Residual of organochlorine pesticides and distribution characteristics in the vegetable soils from Chengdu Region of Sichuan Province,China[J].Ecology and Environmental Sciences,2011,20(3):538-543.
[3]FU J M,MAI B X,SHENG G Y,et al.Persistent organic pollutants in environment of the Pearl River Delta,China:an overview[J].Chemosphere,2003,52(9):1 411-1 422.
[4]胡春华,周文斌,易纯,等.环鄱阳湖区蔬菜地土壤中有机氯农药分布特征及生态风险评价[J].农业环境科学学报,2011,30(3):487-491.HU C H,ZHOU W B,YI C,et al.Distribution and ecorisk evaluation of organ chlorine pesticides in vegetable soil in the area around Poyang Lake,China[J].Journal of Agro-Environment Science,2011,30(3):487-491.
[5]BIDLEMAN T F,LEONE A D.Soil air exchange of organochlorine pesticides in the Southern United States[J].Environmental Pollution,2004,128(1/2):49-57.
[6]GAO H J,JIANG X,WANG F,et al.Residual levels and new inputs of chlorinated POPs in agricultural soils from Taihu lake region[J].Pedosphere,2005,15(3):301-309.
[7]KIM Y B,PARK K Y,CHUNG Y,et al.Phytoremediation of anthracene contaminated soils by different plant species[J].Journal of Plant Biology,2004,47(3):174-178.
[8]潘声旺,刘灿,黄方玉.黑麦草根系分泌物对根际微生物降解有机氯农药的效应[J].福建农业学报,2016,31(8):876-880.PAN S W,LIU C,HUANG F Y.Effect of exudates from ryegrass roots on organochlorine degradation by rhizospheric microbes[J].Fujian Journal of Agricultural Sciences,2016,31(8):876-880.
[9]吴林坤,林向民,林文雄.根系分泌物介导下植物-土壤-微生物互作关系研究进展与展望[J].植物生态学报,2014,38(3):298-310.WU L K,LIN X M,LIN W X.Advances and perspective in research on plant-soil-microbe interactions mediated by root exudates[J].Chinese Journal of Plant Ecology,2014,38(3):298-310.
[10]PHILLIPSA L A,GREERB C W,FARRELLA R E,et al.Plant root exudates impact the hydrocarbon degradation potential of a weathered-hydrocarbon contaminated soil[J].Applied Soil Ecology,2012,52:56-64.
[11]BERTIN C,YANG X.The role of root exudates and allelochemicals in the rhizosphere[J].Plant Soil,2003,256(1):67-83.
[12]MARCHNER H,ROMHELD V,CAKMAK I.Root-induced of nutrient availability in the rhizosphere[J].Journal of Plant Nutrition,1987,10(9-16):1 175-1 185.
[13]SUSARLA S,MEDINA V F,MCCUTCHEON S C.Phytoremediation:An ecological solution to organic chemical contamination[J].Ecological Engineering,2002,18(5):647-658.
[14]LUO L,ZHANG S Z,SHAN X Q,et al.Oxalate and root exudates enhance the desorption of p,p'-DDT from soils[J].Chemosphere,2006,63(8):1 273-1 279.
[15]KIRK J L,KLIRONOMOS J N,LEE H,et al.The effects of perennial ryegrass and alfalfa on microbial abundance and diversity in petroleum contaminated soil[J].Environmental Pollution,2005,133(3):455-465.
[16]潘声旺,刘灿,黄方玉.根系分泌物对土壤中有机氯农药降解的强化效应及其作用机制[J].成都大学学报:自然科学版,2016,35(2):196-200.PAN S W,LIU C,HUANG F Y.Effects of ryegrass root exudates on degradation of organochlorine pesticides in soils and their enhancing mechanisms[J].Journal of Chengdu University:Natural Sciences Edition,2016,35(2):196-200.
[17]袁馨,魏世强,潘声旺.苏丹草对土壤中菲芘的修复作用[J].农业环境科学学报,2009,28(7):1 410-1 415.YUAN X,WEI S Q,PAN S W.The remediation of phenanthrene and pyrene in soil by Sudan grass(Sorghum vulgare L)[J].Journal of Agro-Environment Science,2009,28(7):1 410-1 415.
[18]潘声旺,袁馨,刘灿,等.苯并[α]芘对不同修复潜力羊茅属植物的根系分泌物中几种低分子量有机物的影响[J].植物生态学报,2016,40(6):604-614.PAN S W,YUAN X,LIU C,et al.Effects of benzo[α]pyrene on the organic compounds of low molecule weight excreted by root systems in five Festuca species with different remediation potentials[J].Chinese Journal of Plant Ecology,2016,40(6):604-614.
[19]谢晓梅,廖敏,杨静.黑麦草根系分泌物剂量对污染土壤芘降解和土壤微生物的影响[J].应用生态学报,2011,22(10):2 718-2 724.XIE X M,LIAO M,YANG J.Effects of ryegrass(Lolium perenne)root exudates dose on pyrene degradation and soil microbes in pyrene-contaminated soil[J].Chinese Journal of Applied Ecology,2011,22(10):2 718-2 724.
[20]PAN S W,WEI S Q,YUAN X,et al.The removal and remediation of phenanthrene and pyrene in soil by mixed cropping of alfalfa and rape[J].Agricultural Sciences in China,2008,7(11):1 355-1 364.
[21]李振高,骆永明,腾应.土壤与环境微生物研究法[M].北京:科学出版社,2008.LI Z G,LUO Y M,TENG Y.Methodology of soil environmental microorganism[M].Beijing:China Science Press,2008.
[22]马琨,杨桂丽,马玲,等.间作栽培对连作马铃薯根际土壤微生物群落的影响[J].生态学报,2016,36(10):2 987-2 995.MA K,YANG G L,MA L,et al.Effects of intercropping on soil microbial communities after long-term potato monoculture[J].Acta Ecologica Sinica,2016,36(10):2 987-2 995.
[23]HUANG W,WEBER W J.A distributed reactivity model for sorption by soils and sediments.10:relationships between sorption,hysteresis and the chemical characteristics of organic domains[J].Environmental Science and Technology,1997,31(9):2 562-2 569.
[24]WANG X,SATO T,XING B.Sorption and displacement of pyrene in soils and sediments[J].Environmental Science and Technology,2005,39(22):8 712-8 718.
[25]BEHERA N,SAHANI U.Soil microbial biomass and activity in response to Eucalyptus plantation and natural regeneration on tropical soil[J].Forest Ecology and Management,2003,174(1):1-11.
[26]ISAM H,DOMSCH K H.Relationship between soil organic carbon and microbial biomass on chronosequencse of reclamation sites[J].Microbial Ecology,1988,15(2):177-188.
[27]SHARMA P,RAINA V,KUMARI R,et al.Haloalkane dehalogenase Lin B is responsible forβ-andδ-hexachlorocyclohexane transformation in Sphingobium indicum B90A[J].Applied and Environmental Microbiology,2006,72(9):5 720-5 727.
[28]JAGNOW G,HAIDER K,ELLWARDT P C.Anaerobic dechlorination and degradation of hexachlorocyclohexane isomers by anaerobic and facultative anaerobic bacteria[J].Archives of Microbiology,1977,115(3):285-292.
[29]ADI S P,ICHIRO K,RYUICHIRO K.Degradation of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane(DDT)by brown-rot fungi[J].Journal of Bioscience and Bioengineering,2008,105(6):614-621.