Study On Cinnamomum Migao Population Characteristics In Guizhou

Cinnamomum migao H.W.Li is a endemic species in China,one of the top ten Miao ethnomedicine and traditional chinese medicinal materials of Guizhou Province.Its application and development prospects are very broad,but existing literatures shows: Cinnamomum migao existing stand is mature forest basically,the number of population is in the severe recession.Its protection and exploration of population degradation mechanism are imminent.But the current research on its ecological characteristics and biological characteristics is almost blank.Therefore,this study explored the causes of the decline of the population and the potential of population regeneration by combining means of macroscopic and microcosmic according to the analysis of its population characteristics,phenotypic diversity,genetic structure.Expect to provide a scientific and reliable theoretical basis for the rational development and utilization of the resources.The main results are as follows:(1)The results of percentage of Cinnamomum migao population in the different size classes showed that percent of seedlings and saplings is greater than the sum of percent of small trees,middle trees and big trees,and percent of big trees is greater than the sum of percent of small trees and middle trees.it indicated that small trees and middle trees are seriously missing in Cinnamomum migao natural populations.The results of diameter distribution of Cinnamomum migao population showed that Cinnamomum migao population was gradually decreased with the increasing diameter,and the distribution was presented "J" type curve structure.The results of height distribution of Cinnamomum migao population showed that the height distribution presented a Bimodal type as a whole.The phenotypic of 0 m-12 m stage demonstrated decreased with the increase of tree height,and the stage of 12 m-32 m demonstrated climb up and then decline with tree height’s increase.The power function is better than the exponential function by comparing the power function and the exponential function on the fit effect of the populationstructure.(2)The results of the static state life table of Cinnamomum migao population is showed that the peak mortality rate appeared in the early stage and adult stage.The survival curve analysis showed that Cinnamomum migao population was closer to the type of Deevey III by statistical tested.The loss rate and the mortality rate curve showed that the maximum peak appeared in the stage of seedlings and saplings,the missing diameter was in the mid-stage trees,the number of survival trees indicated "bottleneck" type structure that is presented the number of seedlings and saplings more mid-maturation forest less and mature trees more with age’s increasing.The four survival functions showed that the population was the early reduction slightly,medium-term stability,the late recession,the volatility of the population is great.(3)The spatial pattern of Cinnamomum migao at the different age stages showed as clump distribution in a whole,but the negative binomial parameter decreasing with age’s increasing,the negative binomial parameter of big trees are small and close to random distribution almostly,Cinnamomum migao population from gather to spread gradually with the age’s increasing.The spatial pattern of the population at different altitudes showed that middle altitude is between random and uniform,and low altitude is between clump and random,while high altitude was presented clump distribution which shows a strong negative binomial parameter.Its indicated that Cinnamomum migao like hot and humid low altitude environment,individuals choose clump survival in order to resist the bad growth environment in the high altitude and low temperature environment.(4)The characteristics of phenotypic variation showed that 16 phenotypic traits among populations were significant differences,and the variation among populations was much higher than within population.The percentage variance portions of among populations are higher,the mean value of differentiation coefficients of phenotypic traits(Vst)is up to 95.96%.The phenotypic variation within population showed that the mean value of variation coefficient of 16 leaf traits is 12.06%-23.17%.Leaf width,leaf length and leaf thickness were lower so that its stability higher.Libo1(LB1)population within stability was the lowest and Ceheng(CH)population within stability was the highest because Libo1(LB1)population’s variation coefficient was the highest,while Ceheng(CH)population’s variation coefficient was the lowest.Thecorrelation analysis showed that the correlation of anatomical structures significant and the correlation of apparent measurement traits significant.The principal component analysis showed that the first three principal components could represented most of the information represented by the original factors,vein thickness,palisade tissue thickness,spongy tissue thickness,palisade /sponge,xylem development degree(transection),leaf length,leaf width and leaf area contributed greatly to the main component.The dendrogram of apparent morphology 9 populations showed that Wangmo1(WM1),Wangmo2(WM2),Luodian1(LD1),Luodian2(LD2),Zhenning(ZN)were classified as one class,while Libo1(LB1),Libo2(LB2),Ceheng(CH)and Zhenfeng(ZF)are each class.Its Indicated that the growth conditions are similar when were classified as one class.Cinnamomum migao morphological differentiation is greatly influenced by the growth conditions,different growth conditions promote Cinnamomum migao morphological differentiation.(5)The establishment and optimization of ISSR-PCR reaction system on Cinnamomum migao showed that its bands were most clear and brightest,highest polymorphism and best effect when the concentration of template DNA was 100 ng /20 ul,the cycle index was 35 t,and extending time was 60 s.Although the concentration of template DNA,the cycle index,and extending time have some influences on PCR reaction system,it still have little impact.While annealing temperature’s effect on amplification bands and polymorphism was significant,the differences between the academic annealing temperature and the suitable annealing temperature of the primer is different significantly.The genetic diversity of Cinnamomum migao natural populations showed that 8 populations were amplified 167 polymorphic site by 19 primers,and the percentage of polymorphic site was 89.78%.The value of Na,Ne,H,I,PPB was 1.5726,1.3909,0.3032,0.3282,57.26% respectively.Gst was 0.2636,and the genetic diversity indexes of different natural populations were showed that the indexes of genetic diversity were presented species level > population level on Cinnamomum migao different natural populations,the genetic distance of the 8 populations were not high enough,and the genetic variation among populations were low;the gene flow(Nm)1.3968> 1,indicated that there is a gene flow between among populations,and the genetic differentiation among the populations is small.Principal coordinates analysis(PCo A)showed that 62 samples of Cinnamomum migao were divided into two ancestry obviously,Ancestry 1 was two populations of Luodian,Ancestry 2 contained Zhenning(ZN),Zhenfeng(ZF),Ceheng(CH),the two populations of Wangmo with genetic information of two ancestry.UPGMA dendrogram showed that Zhenning(ZN)was one class;Luodian 1(LD1),Luodian 2(LD2),Wangmo 1(WM1),Wangmo 2(WM2)were a class;Ceheng(CH),Libo(LB),Zhenfeng(ZF)were a class in 8 natural populations of Cinnamomum migao,its indicated that geographic distance close to cluster together.(6)The results of Cinnamomum migao phenotypic diversity analysis showed that the mean value of differentiation coefficients of phenotypic traits(Vst)is up to 0.9596,which indicated that the variation among populations was much larger than within population,The variation among Cinnamomum migao populations was the variation of the phenotype variation’s main source.The results of Cinnamomum migao genetic diversity analysis showed that the genetic differentiation coefficient Gst was 0.2636,which indicated that the variation within Cinnamomum migao population was the main source of genetic variation.In summary,The reason why Cinnamomum migao population is declining is that the process of young individuals is growing into middle-aged trees encounter strong environmental sieve,which makes a large number of individual’s survival so difficult that the population to difficult to enter the replacement layer,forming a bottleneck in the population regeneration and development ultimately.Cinnamomum migao population has a certain reserve of seedlings and saplings.If improving the ecological environment to guarantee the survival development of seedlings and saplings,population can be restored and updated.According to the rich genetic diversity of Cinnamomum migao,the prospect of its genetic improvement is very broad.This is of great significance to the further research of Cinnamomum migao genetic diversity and germplasm resource’s protection and evaluation,the rational development and utilization of natural forests and the cultivation of plantations.