| The paper presented a comprehensive survey of ecological genetic characteristics of Reawnuria soongorica, Anabasis aphylla and Ceratocarpus arenarius distributed in oasis- desert transitional zone in Fukang, Xinjiang. The relationships between the morphological, genetic, physiological and ecological variations and differentiations and the environmental factors were discussed to explain the mechanism of the ecological genetics during the process of evolution and formation of species and provide the theoretical basis and genetic background for planning the scientific strategies of biodiversity conservation.Firstly, we studied the genetic structure and genetic differentiation of Reaumwia soongorica distributed in Fukang, Xinjiang, by the means of random amplified polymorphic DNA (RAPD) markers. The results showed that the higher genetic diversity and the genetic differentiation existed in the population of Reaumuria soongorica, which was composed of 7 subpopulations and 136 individuals, generated by 15 primers. 71 loci had been detected and 69 were polymorphic. The mean proportion of polymorphic loci (PPB) of Reawnuria soongorica was 97.18%. Furthermore, the study discussed the Shannon information index (0.3075), Nei's gene diversity index (0.3127) and Gst (0.3120), which indicated that there were more genetic variations within the subpopulations than those among the subpopulations. The gene flow among the subpopulations of Reawnuria soongorica (Mn=1.1028, Nm>1) was much less than that of the common anemophytes (ATm=5.24), so the species was in the critical state of genetic differentiation to some extent The results of AMOVA showed that there were 61.58% of the total genetic variations existing among the subpopulations, and 38.02% within them. Additionally, through the use of clustering analysis, principal factor analysis and the correlation analysis, we found that the genetic structure of natural population Reawnuria soongorica was related to the ecological factors (soil factors mainly) of the oasis-desert transitional zone. The genetic diversity level ofReaumuria soongorica had the negative correlation with the content of soil total P and Cl" significantly (P<0.05), on the contrary, it had the positive correlation with CO32- significantly (PO.05) but there was no significant correlation between the genetic diversity and the other salt factors in soil, which showed that the distribution of the individuals of Reawnuria soongorica correlated with some certain soluble salt. Furthermore, the study indicated that the genetic diversity of the natural population of Reawnuria soongorica increased with the decreasing of the content of organic matter, water, total N and total P in soil, which had some relation with more potentiality of the genetic and variation of Reawnuria soongorica in its long-term evolution to adapt worse environment. Besides, the paper demonstrated that there was no significant correlation between the genetic distance, genetic diversity and the geographical difference on latitude and longitude respectively within the small range.Secondly, the genetic diversity and genetic differentiation of the two important desert plants of Chenpodiaceae, Anabasis aphylla and Ceratocarpus arenarius, distributed in Fukang Desert, Xinjiang, were studied using RAPD markers. The results showed that the mean proportion of polymorphic loci (PPB) of Anabasis aphylla, which comprised 3 subpopulations (58 individuals sampled), generated by 16 primers was 94.56%, the value of PPB of Ceratocarpus arenarius, which had 4 subpopulations (80 individuals sampled), using 16 primers was 98.00%. The paper had proved that the higher genetic diversity and the genetic differentiation existed in the populations of boih Anabasis aphylla and Ceratocarpus arenarius, while the latter had much moregenetic diversity than the former. Moreover, the study discussed the Shannon information index and Nei's gene diversity index of the two species natural populations, which indicated that there were more genetic variations within the subpopu...
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