Primary Studies On Molecular Ecology Of Suaeda Acuminata Population In Oasis-Desert Transitional Zone In Fukang, Xinjiang--Based On RAPD Data

RAPD technique was applied in this paper to study intraspecific genetic polymorphism and differentiation of Suaeda acuminata population in oasis-desert transitional zone in Fukang, Xinjiang. As a dominant species, Suaeda acuminata plays an important role in maintaining the stability of ecological system in oasis-desert transitional zone in Fukang, Xinjiang. The thesis is intended to study the population genetic structure and intraspecific genetic polymorphism by means of the RAPD analytical technique, and study the space distribution of the genetic variation and the relationship with the ecological factors of the oasis-desert transitional zone. The main results are highlighted in the following:A total of 93 individuals representing 5 subpopulations in oasis-desert transitional zone in FuKang, Xinjiang. By analysis of RAPD data, higher genetic variability was found in the population of S. acuminata with a percentage of polymorphic loci of 98.9%, and we had detected 90 loci of which 89 were polymorphic. A higher level of genetic diversity was detected in Subpop 4 than that in Subpop2, and the genetic diversity followed the orders Subpop4> Subpop2> Subpop5> Subpop3> Subpop 1 by Shannon index. From Shannon index ( / ), genetic diversity in the whole population (//$/>) of S. acuminata was 0.5386 and 72.32% of genetic variation existed within the subpopulations (Hpop/Hsp) , while about 27.68% of which existed among subpopulations (Hsp-Hpop/Hsp} . From Nei's index (//), gene diversity in the whole population (///? was 0.3627, and the gene diversity rate in the five subpopulations (Hs/Hr) was 71.29%, and the genetic differentiation coefficient between the five subpopulations (Gsr) was 28.71%, and its analyticalresults was mainly equable to the Shannon index results. The range of genetic distance among the five subpopulations was 0.0393-0.3643 and the gene flow (Nm) among the subpopulations of Suaeda acuminata was 0.6208. The Suaeda acuminata, as an outbreeding specie, its gene flow was low.The correlation analytical result between the soil factures and the genetic diversity indicted that there was a significant positive relation between genetic diversity and concentrations of Mg"1^ Conductivity (CO) and absorbed water(W) in soil, while there was no significant relation between genetic distance among subpopulations and geographical distance.Analysis of genetic identity, genetic distance and cluster analysis between the five subpopulations showed that genetic differentiation has taken place in the population of Suaeda acuminata in oasis-desert transitional zone in Fukang, Xinjiang. No correlation existed between genetic distance among subpopulations and their locations in oasis-desert transitional zone. Adaptation to its habitats and restricted gene flow among subpopulations may be a cause of genetic differentiation of Suaeda acuminata population in oasis-desert transitional zone in Fukang, Xinjiang.