Study On The Geographic Variations Of Tilia Amurensis Populations And Its Correlation With Environments

Tilia amurensis not only a tamous nectar trees,but also the main raw materlals ofplywoods and blockboards．It is a fine garden tree species with glorious shape,and the flowersand root are used for Chinese traditional medicine．In addition,T amurensis a secondarynatiorlal protection plants．But it attracts little attention to the theoretical study on plantpreservaIion．The researches on me corrclation between geographic variations of T amurensispopulations and its environmental influences at the levels of chemical cornpositions,moleculesare still blank so far．We analyzed geographic variations of the morphology,chemical tomponents,geneticdiversities and its tortelation with environmcnts of various Orans of T amurensis atmacroscopical and microcosmic levels and discussed the elldangered mechanism andconservation strategy by sampling from 9 sample plots in Deciduous broadlcaved forest inwarm temperate zone,Needle and broadleaved mingled forest in temperate zone and Needle-leaf forest in cold temperate zone．Annual branch length,bud length,bud width,leaf length,leaf width,petiole length,bractlength,bract width,concrescence length of petiole and bract,pedicel length,inflorescencelength,flower number,fruit length,fruit width etc．14 kinds of macroscopic indexes,and cellarrange of epidcrmal,shape,stoma,indumentum,number of stoma,stoma,from,outer stomaledge,stoma apparatuses,omamentation,and cuticle of leaves,pollen morphology andcolporate,pericarp indumentum length and characteristics of distribution etc．15 kinds ofmicroscopic indexes were observed and measured．The results showed that anatomical structural characteristics distinctly correlated with thevariatjos of latitude and elevation(mostly negative correlation).Growth status of T amurensistrces was better distributied in central regiotis than in the edges with the changes of latitude。Ftom the point of vicw of elcvltion,700一900m was the optimal altitude for the growth of Tamurensis.The higher the latitude and elcvation were,the looscr the cell arrangement of leafcuticle was,the thicker the thickness of wax coat was；the less irremarkable the changes ofpollen and peel were．There were more hydroxybenzenes,polysaccharides,glucosides,flavone compounds inflowers and buds,and proteins,coumarins,cardiac glycosides,were also detected,in addition,tannins Were found in buds；and hydroxybenzenes,polysaccharides,glucosides,flavones,coumarins and tannins were detected in fruit by systermatic pre-experiments.The determinationof contents of soluble sugars,totaI phenolics and flavones in flowers and fruits of T amutrensiswere displayed that three groups of chemical compositions changed with latitude and altitude． Except total phenolics in flowers,the other contents in flowers and fruits decreased withincreasing of latitude and altitude．The content of soluble sugars in flowers was obvious higherthan in fruits,Other chemical composition contents were similar in flowers and fruits．210 DNA samples from natural populations at different latitudes and altitudes wereselected for PCR amplification with 14 of ISSR primers．The results showed mat T amurensishad fairly high genetic diversities．The genetic diversities of T amurensis decreased with thealtitude increasing,and a single-peak curve was observed with me increase of latitude,andgenetic diversities was higher in central region than in the edges．The correlation betweengenetic distance and geograhic distance Was indistinctive and that between genetic distanceand altitude Was distinctive,but genetic diversity declined with the decrease of altitude．By comparing the cluStering analysis on shape and structure characters and geneticdistance of organs of T amurensis,wc could find that variations of shape and structurecharacters in branthes,leayes,bracts,inflorescence etc．vcgetative Organs were discontinuousat latitudes and altitudes and had no correlations with genetic distance,they mainly derivedfrom environmentaL strsses．However,variations of shape in fruits were continuous atlatitudes and altitudes,and correSponded to genetic distance,which demonstrated that fruitshape was significantly affiected by genetic factors．We testified that the vegetative organs wereplastic and easy to be influenced by environmental changes and reproductive organs weresteady and conservative by our results．The genetic diversity of T. amurensis was high and mainly within the populations, so themainly reason for preservation of T. amurensis was because of cutting, habitat destruction anddegradation but not genetic variations. The protection strategy should be taken to enhance thehabitat protection, avoided from destroying further by mankind, and at the mean time pay moreattention to the preservation of various types of individuals, especially in the core areas.The results would provide the references on choosing good tree species for the forestationand directly breeding cultivars, screen bio-active compositions, establishment forest formedicinal raw materials, and forestation. The results also would provide theoretical foundationfor effective protection and proper utilization of genetic resources of T. amurensis and bebeneficial to practice.