| Cibotium barometz is a second class state protection wild specie and the only Chinese member of the family Dicksoniaceae, which grow in the humid and valley places. It is also used in Chinese traditional medicine in China. It often grows in shady wet ravine and has been fund in Chongqing, Sichuan, Guizhou and Yunnan provinces and cities in the South distribution. In recent years, because of the changes in the environment and the illicit collect by person on the plants, the population dimensions narrows gradually, natural regeneration is difficulty. These factors threaten the population retriever to survive and thrive, its wild resources already endangered. In this study, ISSR and SRAP molecular markers were used to study the genetic diversity on population and individual levels of79Cibotium barometz which were from7populations, to reveal the population and individual levels of genetic diversity, to research the endangered mechanism, so as to provide certain theoretical and practical basis for the species’protection and reasonable use. The results are as follows:1) Cibotium barometz has high genetic diversity:according to the analysis of ISSR and SRAP, diversity coefficient yielded similar results, the PPB are84.78%and85.05%respectively, The Nei’s gene diversity index were0.2505,0.2296respectively, Shannon’s polymorphism information index were0.3904,0.3586respectively. The percentage of polymorphic bands in36.45%～63.33%. Nei’s gene diversity index and Shannon’s polymorphism index size and population percentage of polymorphic loci is consistent, but not identical.The coefficient of populations in CS,BY and PM is higher than that of others.2) Cibotium barometz appeared larger genetic differentiation between populations. Nei’s index and Shannon’s index changes were bigger among different populations, which shows that genetic diversity were diffident on indiviual level. The total gene diversity were0.2496,0.2296respectively, genetic diversity within populations were0.1394,0.1354respectively, population genetic differentiation between index were0.4418,0.4106respectively. The results by2kinds of molecular markers has been basically consistent.3) Populations with similar conditions were clustered firstly, the geographical distribution was not distinctive. Nei’s genetic identity were0.7772-0.9120and0.8307-0.9595respectively, the genetic distance were0.0934～0.2521and0.0414～0.1855respectively. The results by2kinds of molecular markers were similar but not identical. While Geographical distance betteen CS and CN populations, SL and CN are much far, the populations genetic similarity is relatively high,0.9120,0.9595respectively, showed that the relationship of them were closer. While genetic similarity is low, geographical location were near like SL and YH, YH and BW population,0.7772,0.8307respectively, showed that the two kinds of relationship is far away.4) The reason for endangered of Cibotium barometr. The genetic diversity of Cibotium barometz are high at the population level and individual level, suggesting that genetic factors are not the main cause for its being at endangered status. There are three main points as follows:first, Cibotium barometz demand highly on habitat, its population generally grow in environmental of acidic soil, rich content, high density canopy, and the northwest and northeast slope to the edge of the gutter. However, in recent years, because of human factors (such as roads, construction etc.) and the natural environment (such as global warming, drought and other effects), the habitat changes dramatically, they can not adapt and are in endangered. Secondly, Wang Xin confirmed that the spore germination and gametophyte development is hindered and can not retriever new individual because of the companion living with them. Thirdly, the medicinal value has been gradually recognized, people gather illicitly because of its economic value, leading to its natural population decreases, self-renewal difficulties,.5) The protection strategy for Cibotium barometz:First, the environment that Cibotium barometz demand highly, So the in-situ conservation is the best strategy, a high degree of genetic diversity of the populations are the best choose to protected. For protecting the genetic diversity, the environment should be protected, so as to ensure its normal growth and reproduction. Second, with its genetic diversity research and the development of spore germination and gametophyte, establish its gene library and its spore bank, to make sure that its genetic diversity development. Third, along with the development of tissue culture technology. The application of tissue culture technology to ensure the advantage on quantity and then make use of its medicinal value, So that the wild population are not destruction. Fourth, the relevant departments should popularize the protection knowledge, strengthen propaganda and education, so as to avoid the damage of the wild population. |
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