Effects-of-Cd-contamination-l

镉污染对水稻土微生物量、酶活性及水稻生理指标的影响3曾路生1廖敏133黄昌勇1罗运阔2(1浙江大学环境与资源学院资源科学系,杭州310029;2江西农业大学国土资源与环境学院,南昌330045)【摘要】水稻盆栽条件下,研究了外源Cd不同处理对土壤微生物学指标、土壤酶活性及部分水稻生理指标的影响.结果表明,土壤微生物量C和N开始随Cd浓度增加而上升,到一定浓度时则随Cd浓度增加而下降,其转折点因土壤性质有所差异.同时土壤酶活性变化规律与土壤微生物量C、N变化规律相似,但其转折点浓度因土壤类型及土壤酶种类不同而有差异.Cd污染后的变异系数依次为:脱氢酶>酸性磷酸酶>脲酶.土壤呼吸作用强度和代谢熵都随Cd浓度增大而缓慢增加.水稻叶绿素含量随Cd处理浓度增加表现出先上升后下降,其转折点受供试土壤性质不同而不同;脯氨酸含量与过氧化物酶活性随着Cd处理浓度增大而增加.Cd污染后水稻生理指标的变异系数在黄松田水稻土中依次为过氧化物酶活性>叶绿素含量>脯氨酸含量;黄红壤性水稻土中依次为过氧化物酶活性>脯氨酸含量>叶绿素含量.相关分析表明,种植水稻条件下Cd污染对土壤微生物量、酶活性及水稻生理指标的影响是相辅相成的.关键词水稻土Cd污染土壤微生物量土壤酶活性水稻生理指标文章编号1001-9332(2005)11-2162-06中图分类号X17115文献标识码AEffectsofCdcontaminationonpaddysoilmicrobialbiomassandenzymeactivitiesandricephysiologicalin2dices.ZENGLusheng1,LIAOMin1,HUANGChangyong1,LUOYunkuo2(1DepartmentofResourcesScience,CollegeofEnvironmentalandResourceSciences,ZhejiangUniversity,Hangzhou310029,China;2CollegeofLandResourcesandEnvironment,JiangxiAgriculturalUniversity,Nanchang330045,China).2Chin.J.Ap2pl.Ecol.,2005,16(11):2162～2167.ApotexperimentwithriceundersubmergedconditionshowedthatwiththeincreaseofCdconcentration,soilmicrobialbiomasscarbon(Cmic)andnitrogen(Nmic)increasedinitiallybutdecreasedatacertainconcentration,andtheturningpointsvariedwithdifferentsoiltypes.SoilenzymeactivitieshadthesimilarvariationtrendwithsoilCmicandNmic,andtheturningpointsvariedwithdifferentsoiltypesandsoilenzymes.Thevariationcoefficientswereinorderofdehydrogenaseactivity>acidphosphataseactivity>ureaseactivity.Soilrespirationrateandmetabolicquotientincreasedtardilywithincreasingcadmiumconcentration.Thechlorophyllcontentofricein2creasedinitiallybutdecreasedthenwiththeincreaseofCdcontamination,andtheturningpointsdifferedwithdifferentsoiltypes.Riceprolinecontentandperoxidaseactivitywereenhancedgraduallywithincreasingcadmi2umconcentration.Thevariationcoefficientsofricephysiologicalindicesonpaddysoilsderivedfromsiltyloamandclayedredearthwereinorderofperoxidaseactivity>chlorophyllcontent>prolinecontent,andperoxidaseactivi2ty>prolinecontent>chlorophyllcontent,respectiv