| Magnolia biondii pamp, deciduous perennial plant, belongs to Magnolia Magnoliaceae.Dried spathe of Magnolia biondii is real Chinese herbal medicine“XinYi”, which has manymedicine effects: relieve cold, inflammation, hypersensitivity and stuffy nose, Petals can beextracted extractum to make essences as well. The beautiful shape of the tree and its showybrightly colored flowers make it very suitable for cultivation as an ornamental species. AsMagnoliaceae is one of the most primitive group of angiosperms, it has a lot of importantscientific value for the flora; ancient climate and geography research. The genetic diversityand relationship of35wild Magnolia biondii tepal accessions (came from7different regionswhere border areas adjoin each other and all regions in Shanxi、Henan and Hubei province)were analyzed by using ISSR(Inter-simple sequence repeat) markers and agarose gelelectrophoresis techniques. The ultimate objective for thesis is to provide molecular basis fordevelopment of morphological variation theory and genetic diversity conservation, then gofurther into offering useful data for taking scientific and effective conservative measures.1The most suitable ISSR-PCR reaction system and reactive condition of Magnoliabiondii DNA genome was finally established after optimizing (the volume of20ul system):80ng·ul-1template DNA,1.0umol·l-1primer1ul,2×Taq mix (TAKARA)10.0ul, supplementdistill water. The PCR procedure was: predebaturing at94℃for5min,38cycles ofdenaturation at94℃for45s, annealing at a proper temperature (different primers differenttemperatures) for60s and extension at72℃for60s, with7minutes final extension at72℃and then stored at4℃.2In this study,10primers selected from100ISSR primers (published by Columbiauniversity, Canada) with stable and polymorphic characters were used for amplification. Atotal of154bands were generated, of which143bands were polymorphic bands(PPB=93.5%).The highest percentage of polymorphism primers were U806, U808and U825, reach100%.Above all, it’s indicate that Magnolia biondii’s rich polymorphism. 3During Ntsys-PC2.1system processed, the genetic similarity coefficient among35Magnolia biondii germplasms ranged from0.55to0.87. The results showed that there existnot only similar genetic background but also certain different between the accession. Theaverage similarity coefficient of Hubei、Henan and Shanxi is0.7123、0.6871and0.5916respectively. From the data, we can inferred that the evolution tendency of Magnolia biondiigradually get lower from west to east. That is to say, the genetic diversity of western regions(Shanxi) is richer than central plain(Henan) even southern areas(Hubei).4The genetic diversity index value corresponding to any accessions was calculated bypopgene32software. At the species level, number of alleles (Na) was1.9351; effectivenumber of alleles (Ne) was1.4527; Nei’s gene diversity index (H) was0.4274. The aboveparameters indicated that the level of genetic diversity of Magnolia biondii was comparativelyfairly high. The coefficient of gene differentiation (Gst) among3regions was0.1291, it’sshowed that12.9%of the total genetic variation existed between different populations,87.09%occurred within population. A significant genetic differentiation both within andamong different areas, besides, the variation between different populations was relativelylarge proportion of the total differentiation.5Based on the Ntsys-pc2.1software, the clustering dendrogram was constructed byUPGMA method. The UPGMA dendrogram demonstrated that35germplasms were classifiedinto4major groups, based on Nei’s similarity coefficient, which showed that there were somerules in geographical distribution, however, no absolute correlation with tepal color. Theresult of principal coordinate analysis basically accord with the UPGMA dendrogram analysis.Mantel test revealed that genetic relationship among studied accessions was not strictlycorrelated with the geographical provenance.6As the results of all conclusions, we believed that Magnolia biondii species have highergenetic diversity than that within populations, and has a different degree of geneticdifferentiation, besides, destroyed reason is different too. we should take appropriateapproaches to prevent genetic diversity of Magnolia biondii from further losing. |
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