简介：Richgeneticpolymorphismisimportantforplantstoadapttochangesbecauseitenablestheplanttomakeanatomical,physiologicalandbiochemicalchangesinresponsetoabioticstress.Geomorphologiccharacteristics,demographicinterferenceandacumulativedecreaseinfreshwaterinfluxintheIndianSundarbansregionhaveproveddetrimentaltosomeeconomicallyimportantplants.Inthisstudy,geneticpolymorphismofthreemangrovespecies,Xylocarpusgranatum,Excoecariaagallocha,andPhoenixpaludosa,wasassessedusingRAPDandISSRmolecularmarkers.X.granatum,alreadyindistressintheSundarbans,hadtheleastgeneticpolymorphism,14.56%intheRAPDanalysisand12.92%intheISSR.RelativelyhighergeneticpolymorphismwasrecordedfortheprofuselygrowingE.agallochaandP.paludosa:24.66and26.4%inRAPD;24.87and20.32%inISSRanalysisrespectively.AUPGMAdendrogramconstructedusingthesimilaritymatrixfromRAPD,ISSRandcombineddatashowedthatforX.granatum,theleastandhighestsalinityzonesclusteredtogether,whereasforE.agallochaandP.paludosa,higherandlowersalinityareasclusteredindifferentclades.Nei’sgeneticdiversity,calculatedfromRAPDandISSRdata,wasalsoinaccordancewith0.0637and0.0583forX.granatum,respectively,muchlowerthan0.0794and0.0818forE.agallochaand0.0799and0.0688forP.paludosa.ThisopposingdegreeofpolymorphismmightbeattributedtotheprofuselygrowingE.agallochaandP.paludosaandprecariousstatusofX.granatumthroughouttheIndianSundarbans.

简介：Background:Coarsewoodydebris(CWD)isveryimportantforforestecosystems,particularlyforbiodiversityandcarbonstorage.Itsrelevanceasapossiblereservoirandsourceofnutrientsislessclear,especiallyincentralEurope.Methods:Basedonachronosequenceofknownagesoflogs,weanalyzedthenutrientsstoredinCWDofFagussylvatica,Piceaabies,andPinussylvestrisatdifferentsitesinGermany.Toquantifynutrientconcentrations,weassessedtheuseofNearInfraredReflectanceSpectroscopy(NIRS)todeterminethechemicalpropertiesofCWD.Results:NIRSmodelsweresuitabletopredictconcentrationsofC,N,P,ligninandextractives.Concentrationsofmostnutrientsincreasedwithmassloss,withtheexceptionofpotassium,whichdecreasedforbeechandpineandremainedrelativelyconstantforspruce.Thehighestnutrientconcentrations(N,P,S,CaandMn,exceptMgandK)weregenerallyobservedinhighlydecomposedsprucelogs.TheneteffectofdecreasingCWDmassandincreasingnutrientconcentrationswaseitheradecreasing(N,PandKinbeech;P,Mg,KandMninpine),constant(S,CaandMginbeech;N,SandCainpine)orincreasingamountofnutrients(N,P,SandCainspruce;Mninbeech)inthelogsoverthecourseofdecomposition.TheC/Nratiodecreasedforalltreespecies,mostmarkedlyforsprucefromca.1000atthebeginningofthedecompositionprocessto180at36years.TheN/Pratioconvergedtoavalueofabout30forallthreespecies.Ligninconcentrationsincreasedforspruceandbeechandremainedconstantforpine.Conclusions:OurresultsindicatethatmostnutrientsremaininCWDforlongperiods.NutrientsmaybeusedandcycledbymicroorganismswithinCWD,butwiththeexceptionofP(inbeech),Mg(inpine)andK(inbeechandpine),thereappearstobelittlenetnutrientexportuntiltwothirdsofthemassislost.Instead,N,P,SandCawereaccumulatedinsprucelogs,indicatingthatCWDbecameanetsinkratherthananetsourceofsomenutrientsforsevera