The Research On The Conservation Genetics Of The Endangered Species Diplopanax Stachyanthus Hand.-Mazz

Diplopanax stachyanthus Hand.-Mazz. is a relict species and belongs to genus Diplopanax Hand.-Mazz. within the family Araliaceae. D. stachyanthus has long been listed among the Grade II Rare and Endangered Plants in China. Its study will be helpful to the analysis of the the ancient geography and climate, as well as the phylogenetics and morphological evolvement of the Araliaceae and Cornaceae. In this study, we employed a novel set of microsatellites (SSRs) to carry out conservation genetics for D. stachyanthus for the first time.The main results were listed as follows:(1) A total of51pairs of simple sequence were developed followed a slight modification of the Fast Isolation by AFLP of Sequences Containing repeats (FIASCO) protocol. Of the51obtained sequences,34were selected for primer design using Primer Premier version5.0.(2)27individuals from9populations of D. stachyanthus were used to evaluate the utilities of34pairs of primer. Following the discarding of loci due to poor amplification,14microsatellite loci that yielded clear and steady bands were isolated and characterized, with10of them being polymorphic and4are monomorphic loci.(3)10polymorphic microsatellite markers were employed to estimate the genetic diversity of169individuals from9natural populations, and genetic diversity was high at both population (NE =3.06, HE=0.617,I=1.198) and species level (NE=5.03,HE=0.776, I=1.730).(4) Analysis of molecular variance (AMOVA) showed that genetic differentiation among populations was low, in line with the relatively low genetic differentiation between populations (FST=0.178); and the gene flow between the populations (Nm) was1.431.(5) Both Neighbour-joining (NJ) cluster analysis and Principal coordinates analysis (PCA) supported the9populations could be divided into two distinct groups. Furthermore, Mantel test revealed a significant correlation between genetic and geographic distance among populations (r=0.478, P<0.05).These results would offer useful information and evidence for better conservation of the D. stachyanthus from China. Therefore, D. stachyanthus should be protected with maintenance of effective population size and reduction of human destruction. In this thesis, a total of10figures,8tables and105references were included.