| Aquilaria sinensis(Lour.)Spreng,a kind of tambac in China,is a valuable medicinal plant with high medicinal and economic value.With the increase of market demand,the price of tambac keeps raising.Afterward,people begin unrestrained development and predatory logging to the wild resources of A.sinensis,which directly results in the serious living and blocked renewal problems of A.sinensis as well as the accelerated depletion of wild resources.Therefore,our country has listed A.sinensis as the rare and endangered three-level protected plant and the national two-level key protected wild plant.Hence,it is urging to take effective ways to protect A.sinensis resource and strenghten mangement scientifically.(1)Genetic diversity analysis on germplasm resources of A.sinensis: this study used the ISSR to establish firstly the ISSR reaction system of A.sinensis and selected the best experiment project through the investigation of the condition of primer,premix,annealing temperature,nucleic acid dye staining methods and so on.Furthermore,the molecular marker data about 232 A.sinensis in 14 natural populations was got after improving the ISSR reaction system.Using these data,this study researched different natural population of A.sinensis,including their genetic structure,genetic differentiation,genetic distance,genetic diversity and some other things.The main results go as follows,(a)the species diversity of A.sinensis was more than populations diversity;(b)the population genetic identity was between 0.7067 ~ 0.9025,and the genetic distance was between 0.1026 ~0.3471;(c)the genetic differentiation between populations was higher than the genetic differentiation among population.The genetic variation among populations(56.75%)is slightly larger than the genetic variation between populations(43.25%).There was only a weak gene flow between groups(Nm=0.3810)and gene exchange was hindered;(d)the similarity coefficient of UPGMA cluster about the 232 samples in 14 natural populations ranged between 0.66-0.97.When the similarity coefficient is about 0.72,all the populations can be divided into six categories.The samples coming from the same population gathered together to form a relatively independent branch,which states the genetic relationship of germplasm is closely related to the geographical factors.(2)Studies on the phenotypic diversity of different populations: using methods of variance and multiple statistical analysis,principal component analysis and correlation analysis,this paper analyzed and multiply compared 11 phenotypic traits of A.sinensis including leaf length,leaf shape,leaf width and so on to find out the rules of 11 phenotype diversity and population phenotypic variation.The main results are as follows:(a)there were extremely significant differences among 4 quantitative traits among populations of A.sinensis;the order of average variation and relative range were: petiole length > leaf width > leaf length > leaf length-to-width ratio,indicating that the four quantitative traits was stable;the leaf length-to-width ratio was the most stable traits,and the petiole length was the most variable traits;(b)the phenotypic diversity between the population is richer than among groups,which is the main reason for the total phenotypic variation of A.sinensis;in addition,the phenotypic variation between the population mainly comes from the leaf width and leaf length of the four quantitative traits,and the phenotypic variation among the populations mainly comes from the petiole length of the four quantitative traits;(c)from the perspective of population,the average coefficient of variation for quantitative traits of different populations was: Yangchun,Yangjiang,Guangdong > Gangqiling,Huiyang,Huizhou,Guangdong > Mt.Manjin,Jinghong,Yunnan > Maoming,Guangdong >Mt.Dinghu,Zhaoqing,Guangdong > Mt.Bawang,Changjiang,Hainan > Che village,Boluo County,Huizhou,Guangdong > Hainan Pharmaceuticals Plantation,Wanning,Haikou,Hainan > Sanjiang town,Meilan,Haikou,Hainan > Mt.Yinhu,Shenzhen,Guangdong >South-china medicinal park,Jinghong,Yunnan > Mt.Daling,Dongguan,Guangdong >Xunliaowan,Huidong,Huizhou,Guangdong > Mt.Wugui,Zhongshan,Guangdong.Therefore,Yangchun,Yangjiang,Guangdong has the most abundant phenotypic diversity,and Mt.Wugui,Zhongshan,Guangdong has the least phenotypic diversity;(d)the principal component analysis shows that the phenotypic variation of A.sinensis can be described by five principal components representing the original 11 phenotypic traits.The first and second principal components mainly represent 4 quantitative traits and leaf shape;the third principal component mainly represents the change of bifurcation angle;the fourth and fifth principal components mainly represent the symmetry of leaf and the bifurcation of secondary veins.(3)Preliminary Construction of Core Collection of Aquilaria sinensis(Lour.)Spreng:The paper also used UPGMA clustering method to classify the 232 A.sinensis individuals,and investigated the 3 sampling methods of Stepwise clusters with random sampling strategy(SCR),Least distance stepwise sampling(LDSS)and Random sampling cluster strategy(RS),and the 8 sampling proportion from 5% to 40%.As a result,LDSS was selected as the best sampling method,and 35% sampling rate was chosen as the best sampling proportion.82 germplasm was selected as the core germplasm from the 232 original germplasm,initially constructed the core germplasm of Aquilaria sinensis.T test showed that there was no significant difference in genetic diversity between the core germplasm and the original germplasm for their several genetic diversities level is equal to0.05,and the genetic diversity of the original germplasm could be preserved about 97.65%~99.34%This study to the genetic diversity and phenotypic diversity of A.sinensis will provide abundant basic data for the research of A.sinensis.The preliminary research on the corecollection of A.sinensis will also built a foundation for the preservation,management,evaluation and utilization of A.sinensis germplasm resources. |
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