中国科学院昆明植物研究所知识管理系统(KIB OpenIR): Search Results

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Funding Project：Begonia L. belongs to the family Begoniaceae. Begonia species in China are mostly distributed S of Yangtze River, particularly concentrated in SE Yunnan and SW Guangxi, with only a few extended into N China. The thesis includes investigation and introduction of the genus Begonia from SE Yunnan and SW Guangxi. Preliminary studies on seed germination, seed storage characteristics, DNA content analysis of in vitro conservation Begonia species, seed morphology and pollen morphology were conducted. The main results were summarized as follows:1. Morphology,⑴ Seed morphological study, Seeds of three species of the Chinese Begonia Sect. Coelocentrum and ten species of Sect. Platycentrum were studied. The result showed that there was higher consistency in Sect. Coelocentrum and the seeds morphology had certain value at sectional level. In addition, the Chinese Begonia Sect. Platycentrum had high diversities in seed micromorphology especially in the aspect of the shape of operculum and the size of seed. The seed morphology of the same species showed steady characters.⑵ Pollen morphological study, Pollen of 21 Chinese Begonia species was examined. The results showed that striate was the most commonplace exine sculpture pattern among Begonia as well as punctuate, rarely rugose. Although the pollen morphology did not show its importance to the taxonomy at sectional level of the genus Begonia, it showed some value to some specific treatment. Our study also suggested that the species with middle pollens in Begonia could be more primitive, while the species with smaller or larger ones might be much advanced.2. Conservation of germplasm resources,⑴ Conservation status, There are only three populations of B. purpureofolia and two populations of B. pseudodryadis according to investigation. The total mature individuals ofthe two species are less than 2500 and no subpopulation estimated to contain more than 250 mature individuals. Based on the IUCN Red List Categories and Criteria (Version 3.1), the conservation status of B. purpureofolia and B. pseudodryadis is ranged as Endangered. ⑵ Introduction and cultivation, The species were collected mainly from SE Yunnan and SW Guangxi. Living environment, growing conditions, physical and chemical characters of soil samples of B. purpureofolia and B. pseudodryadis were studied. Then the suitable condition was obtained to cultivate the two species.⑶ Seed germination and storage characteristics, The effect of temperature on seed germination of thirteen Begonia species were studied. The results of the test were as follows: temperature had no significant effect on seed germination percentage on most of the studied Begonia species but had a significant effect on mean germination time (MGT). Storage characteristics of three species of Begonia were studied by setting different storage temperatures (ambient temperature, 4℃ and -20℃) and storage periods (30d, 60d, 90d and 180d). The results showed that the seeds storage in ambient temperature and 4℃ had higher germination percentage than -20℃. ⑷ Assessment of genetic stability, Flow Cytometry (FCM) analysis was used to assess the genetic stability in three Begonia species which were maintained in vitro for a period of over 10 years. The results showed that no significant variation in the nuclear DNA contents of B. cathayana and B. pseudodryadis. However, long-term in vitro maintenance induced aneuploid change in nuclear DNA contents in B. hemsleyana

中国科学院昆明植物研究所知识管理系统

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