UV-irradiationandshadechangetheconcentrationofcatalpolinRehmanniaglutinosaseedlingandrhizosphere#ZhangPeipei1,ZhangZhongtian1,GuiMengyuan2,WangTaixia1**51015202530354045(1.CollegeofLifeScience,HenanNormalUniversity,HeNanXinXiang453007;2.CollegeofLifeScience,NorthWestUniversity,Xi'an710069)Abstract:ResearchwasconductedonRehmanniaglutinosaLibosch.,aChinesetraditionalmedicinalplant,toinvestigatetheeffectsofUV-irradiationandshadeontheconcentrationofcatalpolinseedlingsandrhizosphere.Theplantsweregrownunderthreeirradiances:fulllight,partialshade(50%fulllight),andUV-irradiation.TheR.glutinosaseedlingswereharvestedandthehydroponicculturesolutioninthecontainerswascollectedonday3,6,9,12,15aftertreatmentrespectivelyfordeterminationofcatalpol.TheresultsshowedthatUV-irradiationincreasedtheconcentrationofcatalpolinleavesrapidlyattheearlystage,andthen,insteadofincreasing,theconcentrationofcatalpoldecreasedalittle.Incontrast,thecatalpolcontentinR.glutinosaleaveswasreducedunderpartialshade.SimilartrendswereobservedinrootsandstemsofR.glutinosaunderUV-irradiationandshade.Theconcentrationofcatapolinmediuminwhichfull-light,shadeandUV-irradiatedseedlingsweregrownallincreasedwithtime.ButtheconcentrationofcatapolinmediumofUV-irradiatedseedlingswasgreaterthanthatoffull-lightseedlings,andtheconcentrationofcatapolinmediumofshadeseedlingsislower.Therefore,UV-irradiationincreasedbothproductionofcatalpolinR.glutinosaseedlings,andsecretionofcatalpolintoR.glutinosarhizosphere.OnthecontraryshadingdecreasednotonlyproductionofcatalpolinR.glutinosaseedlings,butalsosecretionofcatalpolintoR.glutinosarhizosphere.ItwasalsofoundthatUV-irradiationdecreasedtherootvigorandpartialshadingincreasedtherootvigorofR.glutinosaseedlings.Keywords:Rehmanniaglutinosa;Catalpol;Rhizosphere;Shade;UV-irradiation;Rootvigor0IntroductionRehmanniaglutinosaLibosch.isaperennialmedicinalplantandbelongstothefamilyScrophulariaceae.Forcenturies,ithasbeenthoughtasa“topgrade”herb[1]andmanyorientalmedicalbooksincountriessuchasChina,JapanandKoreahavelistedthisplant’srootbecauseofitsmedicinalpurposes[2].R.glutinosaisbasicallythoughtasadrugfornourishingandtonifyingthekidney.InrecentdecadestherehavebeenmanyreportsofthepharmacologicalfunctionsandactivitiesofR.glutinosaanditsactiveprinciplesonthebloodsystem,immunesystem,endocrinesystem,cardiovascularsystemandnervoussystemandofanti-tumor,anti-senescence,etc[3,4].SoR.glutinosaiswidelycultivatedandvaluedforitsmedicinalproperties.Butitcan’tbecroppedcontinuously.GeneralyR.glutinosacanbecultivatedagainonthesamesoilonlyafter8yearsto10years[5].Therefore,thecontinuouscroppingobstaclehasbeenthemajorprobleminR.glutinosaagriculturalproduction.Manyreasonswerereportedforcontinuouscroppingobstacle.Rootexudatewasthemainone[6-9].CatalpolwasoneofsecondarymetabolitesinR.glutinosarootandcouldbesecretedfromrootstotherhizosphere[10].ItwasreportedthatUV-irradiation[11,12]andshading[13]couldincreasetheconcentrationofsecondarymetaboliteinplant.However,thereisnoinformationavailableregardingwhetherUV-irradianceandshadingincreasetheconcentrationofcatalpolinR.glutinosaandthesecretionofcatalpolintoitsrhizosphere.ThepurposeofthepresentexperimentswastoinvestigatewhetherUV-irradiationandshadehaveeffectsonconcentrationofcatalpolinR.glutinosaseedlingsandthesecretionofcatalpolintoR.glutinosarhizosphere.Therootsvigorwasalsocarri...