| In this study Prunus divaricata Ldb.endemic wild fruit tree of Xinjiang were studied at four leves such as community species diversity, henotypic diversity, genetic diversity and endangered species conservation. The main research results were as follows.1. The Prunus divaricata distribution area in Da xiao xi gou is abundant in plant resource, the total plant 98 species belongs to 36 families 84 generaand. There were 22 species of tree and shrub plants belonging to 15 generaand 6 families and 76 species of herb plants belonging to 69 generaand 30 families. Study on different life forms such as tree layer, shrub layer and herb layer in Da xiao xi gou plant community we found the Margalef index is 0.95,1.28 and 5.61, the Simpson index is 0.7,0.83 and 0.94, Shannon-Winner index is 1.34,1.93 and 3.2,three different index show that the species richness order was that the herb layer> shrub layer>tree layer. The vertical variation of species diversity in Prunus divaricata distribution area is concentrate on the range of 1000-1500 meter. The species diversity, evenness and diversity index variation trends are similar. They all shows a trend of rise first then fall and the peak value occurred in 1000-1300 meter. The dominant species of Daxiaoxigou plant community is mainly includes Prunus divaricata, wild hawthorn, wild apple and wild apricot. The plant community was divided into 4 main community types based on the dominant species and the importance value. The result embodied community types character of this area.2. Based on 8 natural populations and 20 phenotypic traits we found that difference was significant between different natural populations. The mean of coefficient variation between different natural populations is 7.82-19.76, the mean of coefficient variation in different natural populations is 6.96-40.9%, phenotypic difference in different natural populations is higher than the value between different natural.Comparison with percentage of relative range and phenotypic coefficient variation we found that the variation range is not change much. The principal component analysis shows that the phenotypic index such as fruit length, fruit width, nutlet weight, leaf length, corolla diameter, fruit stalk, shoot length, shoot diameter, fruit hardness are main factors which provoked character variation between different natural populations. Cluster analysis research shows that Prunus divaricata 8 natural populations divided into 3 main group. The cluster result agreed with the actual situation of geographical distribution, it is also match with the environmental features and the habitat of distribution area. 3. SSR-PCR reaction system of Prunus divaricata is established. That optimistic RCR system of 20μL which contained 0.2mmol/L dNTP, 1.0mmol/L Prime, 1.0mmol/L Mg2+,1.0 U Taq DNA polymerase, 1μl template DNA and 35 times cycle. SSR was adopted to study 50 germplasm materials of Prunus divaricata,771 bands were detected with 5 pairs of primers and 330 of them were polymorphic, the mean proportion of polymorphism was 154.2, which amounted to 42.8%. Among 7 natural populations polymorphic loci detection, the rich degree order sorting is Menggumiaogou>Xiaoxigou>Yidaogou>Hemantan>Majintanggou> Miaoergou>Apeiyinggou. The genetic variation being 86.05% within the Prunus divaricata natural populations and 13.95% among the natural populations. The genetic similarity and genetic distance showed that Yidaogou and Hemantan natural populations had the nearest relationship and the Nei genetic distance was the largest in the Xiaoxigou and Majintanggou natural populations.They had higher genetic differentiation degree.7 natural populations was divided into 4 main group based on the average genetic distance(0.78) clustering. The results are consistent with the SSR clustering and the phenotypic clustering.4. Endangered mechanism of Prunus divaricata germplasm resources analysis revealed that the results caused by interaction of various factors, and its related with the breeding system restriction and the environmental deterioration. The incoordination was caused by superimposed effect which from biological characteristics and between the biological characteristics and the external environment We should strengthened kynamics on site protection, relocation protection, legal system construction and scientific research, at the same time in vitro conservation gene bank should be established. We should also pay attention to development and utilization reasonable and make it closely combined with protection and utilization on wild Prunus divaricata germplasm resources. |
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