不同硝铵比值对小麦幼苗根系释放氢氧根的影响郭都

2012284427－431JournalofEcologyandRuralEnvironment/121①1.2100082.100049pH。pH4.0nNO－3∶nNH+4/15∶1、3∶11∶16dpH/pH。/3∶1pH4.0、4.55.06dpHpHpH。10hpHpHpH。pH。/S156A1673－4831201204－0427－05EffectofNO－3/NH+4MolarRatioonHydroxylReleaseFromWheatRoots．GUODu12XURen-kou11．StateKeyLaboratoryofSoilandSustainableAgricultureInstituteofSoilScienceChineseAcademyofSciencesNanjing210008China2．GraduateUniversityofChineseAcademyofSciencesBeijing100049ChinaAbstractInordertodevelopmethodsforbioremediationofacidsoilshydroxylreleasefromrootsofwheatseedlingsinahydroponicexperimentasaffectedbyformofnitrogenfertilizerunderacidicconditionswasinvestigatedwithanautomatictitrationsystem．ResultsshowthatpHofthenutrientsolutions4.0ininitialpHand15∶13∶1and1∶1inNO－3/NH+4molarratioseparatelyincreasedafter6daysofwheatculturing．Thehigherthemolarratiothegreatertheincreaseinso-lutionpH．Correspondinglytheabsorptionofnitratebywheatandthereleaseofhydroxylfromwheatrootsalsoincreasedwiththerisingmolarratio．Thesefindingssuggestthatthepreferentialabsorptionofnitratebywheatandsubsequentre-leaseofhydroxylfromwheatrootscauseincreaseinsolutionpH．InsolutionsthesameinNO－3/NH+4molarratiobeing3∶1andvariedininitialpHtheincreasesinsolutionpHandhydroxylreleasefollowedtheorderofinitialpH4.0＞initialpH4.5＞initialpH5.0suggestingthatlowerpHconditionfavorsnitrateuptakebywheatandhydroxylreleasefromwheatroots．A10-hourpH-statexperimentshowsthatwheatrootsreleasedmorehydroxylunderpH-statconditionsthanundernon-pH-statconditions．Thehigherthemolarratiothegreaterthedifference．Itisthereforefeasibletode-velopanewmethodforbioremediationofacidsoilbasedonthepreferenceofwheattoabsorbnitrateandreleasehydroxylfromrootsunderacidicconditionsthatistosaytoincreasethereleaseofhydroxylbyregulatingnitratecontentinthesoilandhencetoincreasesoilpH．KeywordswheatNO－3/NH+4molarratiohydroxylreleasesoilacidificationbioremediationmethod2012－01－10KZCX2－EW－405①[e-mail]14、203km221%1。。2。pH3－4。H+5－6。H+7－8。·428·28CO2、、pH9。NH+4H+HCO－3NO－310。。pHpH11－12。、pH13－14。15pH。pH、。。11.113。1.225℃。。1。31311/31L。。Hoaglands。nNO－3∶nNH+4/NaNO3NH42SO4/。16h25℃65%12000lx8h20℃90%。1.32。1pH4.04/15∶1、3∶1、1∶11∶34mmol·L－12/3∶13pH4.0、4.55.0。3。2dpH1pH6。pHpH4.05/15∶1、3∶1、1∶1、1∶31∶15pHH2SO4pH10h。pH。。3。1.4pHpH。0.01mmol·L－1H2SO4pHH+。NH+4NO－3NH+4NO－3NH+4NO－3。1.5SPSS15.0。22.1/pH/pH1。1pH4.0/1∶33pH/P＜0.05。pH。6d1。1/15∶1、3∶11∶1/4/·429·/15∶1P＜0.05/1∶31pH。/P＜0.05//。1/pHFig．1DynamicsofpHinwheatculturesolutionasaffectedbyNO－3/NH+4molarratio1/、Table1TotalamountofOH－releasedfromwheatrootsandamountsofNO－3andNH+4absorbedbywheatasaffect-edbyNO－3/NH+4molarratioofthesolution//mmol·L－1/mg·L－1/mg·L－115∶10.89±0.05a50.26±1.35a3.50±0.00a3∶10.12±0.04b39.11±3.23b7.46±0.29a1∶10.04±0.01b24.88±2.46c30.91±1.60b1∶30.00±0.00c11.05±1.16d34.80±2.14cP＜0.05。2.2pHpH/3∶1pHpH2。2pH4.04.5pH6pH0.840.29pH5.0pHpH。pHpHpH。pH5.0pHpHH+pH。2pHpHFig．2DynamicsofpHinwheatculturesolutionasaffectedbyinitialpHpH2。2pH4.0、4.55.0pHpH4.04.5pH5.0P＜0.05。pH。。pH4.0pH4.55.0P＜0.05pH。2pH、Table2TotalamountofOH－releasedfromwheatrootsandamountsofNO－3-N/NH+4-Nabsorbedbywheatasaf-fectedbyinitialpHpH/mmol·L－1/mg·L－1/mg·L－14.00.12±0.04a39.11±3.23a7.46±0.29a4.50.11±0.01a31.36±2.07a11.91±0.47b5.00.02±0.01b20.58±1.41b11.32±0.89b/3∶1。P＜0.05。2.3pHpHpH。3pH4.010h·430·28/P＜0.05pH。1h/15∶1、3∶11∶1/15∶14h/3∶11∶1。10hpHpH3。pHpHP＜0.05。3/15∶1、3∶11∶1pHpH1.97、2.072.13。。3pHpH。/15∶1、3∶11∶1pHpH1.39、1.641.39。pH。3pHFig．3Dynamicsofhydroxylreleasefromrootsofwheatseedlingsinthe10-hourpH-statexperiment3pHpH、Table3TotalamountofhydroxylreleasedfromwheatrootsandamountsofNO－3-NandNH+4-NabsorbedbywheatfromnutrientsolutionsunderpH-statandnon-pH-statconditions//mmol·L－1pHpH/mg·L－1pHpH/mg·L－1pHpH15∶10.063±0.003a0.032±0.007a21.85±0.90a15.68±0.84a1.98±0.18a1.71±0.08a3∶10.060±0.004a0.029±0.003b17.32±1.40b10.57±0.73b2.31±0.12a2.06±0.13a1∶10.049±0.004b0.023±0.008c15.77±0.81b11.36±0.37b9.08±0.59b10.92±0.43b1∶30.031±0.003c0.026±0.005d8.19±0.59c3.73±0.16c13.37±0.57c16.65±0.68c1∶150.024±0.002c0.023±0.006d2.23±0.73d1.15±0.08d18.19±0.97d15.53±0.56cpH4.0。10h。P＜0.05。。SMI-LEY16pH。。pHNO－3NO－3H+17。YAN18pHATP。pH4.0pH4.55.0pHpH。pH。3pHpH/。pH。4/·431·pHpH。pH。1．J．2003295361－366．2GUOJHLIUXJZHANGYetal．SignificantAcidificationinMajorChineseCroplandsJ．Science201032759681008－1010．3HELARKR．NitrogenCyclingandSoilAcidificationJ．TheJournaloftheAustralianInstituteofAgriculturalScience1976422217－221．4．J．200925442－4599．5CREGANPSCOTTB．SoilAcidificationAnAgriculturalandEn-vironmentalProblemC∥PRATLEYJEROBERTSONA．Agri-cultureandtheEnvironmentalImperative．CollingwoodAustraliaCSIROPublishing199898－128．6XURKCOVENTRYDRFARHOODIAetal．SoilAcidificationasInfluencedbyCropRotationsStubbleManagementandAppli-cationofNitrogenousFertiliserTarleeSouthAustraliaJ．Aus-tralianJournalofSoilResearch2002403483－496．7SCHUBERTSYANF．NitrateandAmmoniumNutritionofPlantsEffectsonAcid/BaseBalanceandAdaptationofRootCellPlasma-lemmaH+ATPaseJ．ZeitschriftfürPflanzenernhrungundBodenkunde19971603175－281．8TANGCRAPHAELCRENGELZetal．UnderstandingSubsoilAcidificationEffectofNitrogenTransformationandNitrateLeac-hingJ．Aus