| In this dissertation, following the basic principles of ecology and conservation biology, and with the help of the statistical analysis, cluster analysis and principal components analysis, the author studied the morphological differentiation and genetic diversity of S. tsinyunensis which is endemic to Jingyun Mountain of Chongqing from morphological and allozymic levels in order to reveal the mechahism of its population adaptation and genecological differentiation. The results show as follows: 1. Morphological differentiation. With the help of the method of numerical statistic, the author studied on 36 morphological characters of 70 individuals from 7 populations from different habitats. Statistical analysis revealed that there exits somewhat variations in morpholgy of S. tsinyunensis within a certain population or among different populations. Among the 36 morphological characters we analyzed, the variation of the base-leaf organs of S.tsinyunensis is more obvious than that of the stem and the top-leaf organs. The variations of the leaf shape and angle are comparatively the least remarkable. Variance analysis shows that the difference of many studied morphological characters (77.8%) is significant among populations, of which 6 1.1% characters even show extremely significant among populations. Among the 36 morphological characters, the difference of the top-leaf organs of S. tsinyunensis is more significant than those of the proportion of the leaf shape and the stem organs. The differences of the angle and the base-leaf are the least significant. Both the cluster analysis and principal components analysis indicate that the overall morphological differentiation of S. tsinyunensis is somewhat unordered. That is to say, the individuals of different populations often fall into the same cluster, but most individuals within the same population often fall into the same cluster. It can be inferred that there are certain amounts of morphological differentiation among populations, but the differentiation is not significant enough to distinguish the population clearly. 2. Genetic differentiation. The genetic structure and variation of 7 populations of S. tsinyunensis were investigated based on allozyme analysis using the techniques of polyacrylamide gel electrophoresis. The results show: S. tsinyunensis maintains relatively high genetic diversity. The proportion of polymorphic loci(P) is 45.7%, average number of alleles per locus(A) is 1.46, mean expected heterozygosity(H~) is 0.205, and mean observed heterozygosity(H0) is 0.352. The allozyme bands show that there are some bands (ca. 22.2%) which are permanent to all populations of S. tsinyunensis. It proves that 7 populations of S. tsinyunensis have certain genetic identity interpreted from the allozyme band analysis. There is high proportion of unique allozyme bands among populations. There are 8 allozyme bands which are unique to one of the populations respectively, meanwhile, population No. VI is salient which has 4 unique allozyme bands. The fixation indexes (F) of population No. I and population No.111 are close trend to 0 among 7 populations, while all the others deviate from 0 Quite a lot. The fixation indexes show heterozygote deficiency in population no.Vll, but excess in population No. II , No.IV, No. V and No.VI. S. tsinyunensis maintains relatively high level of genetic variation among populations. GsT is 0.401, and the means of genetic identity and genetic distance are 0.741 and 0.300 respectively. The genetic distance between population no.111 and no.IV is t... |
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