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Study On Genetic Diversity Of Endemic Endangered Plant Dysosma Versipellis

Posted on:2003-12-26Degree:MasterType:Thesis
Country:ChinaCandidate:Z C LiFull Text:PDF
GTID:2120360062985990Subject:Botany
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A total of five populations of Dysosma versipellis were sampled from Mt.Emei in Sichuan Province(SC), Mt.Shengnongjia Hubei in Province (HB), Mt.Tianping in Hunan Province (HN), Pengze in Jiangxi Province (JX), Mt.Tiantangzhai in Anhui Pprovince (AH), and a population of Dysosma pleiantha from Mt.Tianmu in the Rangzi River drainage area of Zhejiang Province (ZJ). Together, these are considered a good representation. Of the species , .characters of ecology, reproductive biology, genetic diversity, population genetic structure, endangering mechanisms, and sampling strategy have been studied in view of conservation biology. The results may be summarized as follows:By field investigation , we found that the localities recorded for four specimens of D. versipellis and D.pleiantha had disappeared, and most of the present populations are located in protected subforests. The distributional range of D. versipellis has also been reduced greatly , Evidently, the number of present populations has decreased, the resources are reduced sharply , and the species are clearly endangered.Studies on population ecology showed that D. versipellis is able to grow on the hillsides of subtropical broadleaf or acicularleaf secondary forest where soil is fertile and the content of N, P, K is high and the pH is 5.49-6.59. In its spatial pattern, the species is distributed in clump, and individuals of sexual maturity are few as a result of poor water, light, seed dispersal, and human activities. Also the populations tend to grow slowly. There were some differences in morphology between popolations of D. versipellis, owing to spatial isolation. Some individuals even appear to take on characteristics of other species in the genus Dysosma. Since the species exhibits many disadvantageous biological characteristics, sexual reproduction of D. versipellis was low. However, D. versipellis also processes vegetative reproduction by rhizome and root.Based on optimization of reaction conditions and systems, RAPD-PCR was performed to detect the genetic diversity and popolation-genetic structure of the five D. versipellis populations and are D. pleiantha population. The results of analysis usingPOPGENE software are as follows:1. The percentage of specific polymorphic loci (SPB) was 70%, and the percentage of population polymorphic loci (PPB) varied from 14% to 20%. And HN population amount was the highest (20%), whereas the JX population was the lowest (14%), which indicated low genetic diversity within population and little variability among populations.2. The total genetic variation (Ht) was 0.2402, and genetic variation within population was 0.0668. Genetic differentiation (Gsf) was 0.7221, and gene flow (Nm) was low (0.1924).3. Cluster analysis based on Nei's genetic distance showed that the SC population clustered with the AH population first, suggesting that despite differentiation among populations, genetic distance was not related to geographic distance in D. versipellis.4. The ZJ population of D. pleiantha was easily distinguished from D. versipellis.5. The results of analysis among the six populations (D. versipellis and D. pleiantha) and the five populations (D. versipellis ) agreed with each other. Namely, the show low genetic diversity within populations and little variability of genetic level among populations.The analysis using AMOVA155 software are as follows:1. The ZJ population hit the highest peak of sums of squares(127.8358), and AH population hit the lowest peak of sums of squares(100.2228). The others were close to the AH population. Variance within populations was 29.11%, whereas variance among populations was 70.89%.2. The six populations were separated into two groups (the D. versipellis group and the D. pleiantha group, or the south of Rangzi River group and the north of Rangzi River group), and the five populations were separated into two groups (the south of Rangzi River group and the north...
Keywords/Search Tags:Dysosma versipellis, conservation biology, RAPD-PCR, genetic diversity, endangered mechanism, conservation and sampling strategy
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