Population Distribution Pattern And Genetic Diversity Of The Desert Relict Plant Gymnocarpos Przewalskii

In order to study the population characteristics and dynamics of Gymnocarpos przewalskii,and understand the population distribution types of G.przewalskii and their degree of agglomeration,the spatial distribution patterns of 4 G.przewalskii populations of Xinjiang were analyzed by the plant height,crown width,variance/average ratio,negative binomial distribution parameters,clumping index,patchiness index and Cassie index.At the same time,conducted correlation and principal component analysis of environmental factors and population spatial distribution.To understand the genetic diversity and genetic structure of G.przewalskii.201 individuals sampled from 7 populations of G.przewalskii in Xinjiang were analyzed by using start codon targeted(SCo T)markers.The above research provide basic data for further protection of G.przewalskii.The main results are as follows:The age structure of Hami,Luntai and Kuqa populations belongs to the stable population,but Hami population was in the declining state due to less young plants.The age structure of Wuqia population was the expanding population,and the number of more young plants give it the strong growth potential.The distribution patterns of the four G.przewalskii populations were clumped distribution,but the degree of aggregation of different G.przewalskii populations was different.The degree of aggregation of Hami,Luntai,Kuqa and Wuqia population was in descending order.The negative binomial index of Wuqia population was significantly lower than Hami population.The distribution pattern of G.przewalskii at different stages of growth and development also showed clumped distribution,but the degree of aggregation at different stages of growth and development was different,and the overall performance in order to increase the degree of aggregation as the age increases.The distribution pattern of G.przewalskii population were affected by the distribution pattern of G.przewalskii population are annual precipitation,soil salinity and p H,followed by annual sunshine hours,human disturbance and soil organic matter.Annual mean temperature and annual relative humidity had little effect on it.The results showed that 12 random primers were amplified to 145 loci.The percentage of polymorphic bands at the species and population level was 97.24 % and 76.45%,Nei's genetic diversity indices at the species level and population level was 0.2638 and 0.2137,Shannon's information diversityindex at the species and population level was 0.4081 and 0.3316.These results indicated that the genetic diversity of G.przewalskii was higher,and species level genetic diversity is lower than population level.The genetic differentiation coefficient was 0.1839,which indicated that the genetic variation of G.przewalskii mainly existed in populations,differentiation among populations exists partly.Mantel test revealed that the correlation between geographic and genetic distances of G.przewalskii population is not significant.The results of principal coordinate analysis(PCo A)and genetic structure analysis were some differences,but basically consistent with each other.In summary,G.przewalskii population were clumped distribution,the differences in the degree of aggregation of G.przewalskii population at different habitats and development stages were due to the combined effects of biological characteristics of G.przewalskii and environmental factor.The present status of genetic diversity and genetic structure of G.przewalskii might be related to its evolutionary history,breeding system,geographical isolation and human disturbance.