Symbiotic Germination Of Dendrobium Sinense (Orchidaceae), Endemic In Hainan Island

Orchidaceae is the third largest Family in higher plants, some orchidaceaes have not only ornamental value and scientific value, but also great economic value and officinal value. Dendrobium is the second largest Genus of Orchidaceae, which has ornamental and officinal value. Market demand results in over-digging, as a consequence, wild Dendrobium are badly damaged, even dying out in some areas. In China, there’re 77 kinds of original Dendrobium,15 of which are in Hainan province, and Dendrobium sinense is unique in Hainan that is critically endangered.Orchidaceae are typical mycorrhizal plants. Mycorrhiza fungi could be commensal with seeds, protocorm, and nutritiveroot of Orchidaceae, and it supplies nutrition for their growing. Mycorrhiza fungi are irreplaceable for the life history of normal Orchidaceae. Therefore, studying nursing mechanism of D. sinense from mycorrhiza fungi’s point has great significance for endangered wild Orchidaceae.Firstly, this research was to isolate Neotyphodium from self-germinating wild D.sinense protocorm, and screened out beneficial endophytic fungi which could promote the growing of D. sinense. Then did experiment on symbiotically germinating. Secondly, the paper would talk about the techniques of symbiotically germinating of D. sinense’s seed both in-situ and ex-situ,To explain the relationship between Dendrobium’s seed germination and planting time, epiphytic species and habitat conditions, in order to find the key factor in seed germination of Dendrobium sinense. And I hope I can find some efficient technical support for protecting and making use of D. sinense.Main conclusions:1. Used symbiotically germinating technique, through in-situ seeding, we could get lots of protocorm, which reveals the germinating rules of D. sinense:the number of self-germinating wild D.sinense protocorm were pretty few, in-situ artificial seeding could increase the number obviously and the creation rate.; different epiphytic hosts had differences; the number of germinated protocorm in epiphytic host were very much relevant to the distance and seeding time of the D. sinense.2. Simulated the germinating in the lab, we find the time was much shorter than in wild, and protocorm germination were relevant to the part of bark and nutrition of bark.3. Simulated the germinating in the lab, in the improvement of OMA medium which was No.7 suitable for the symbiotic germination.4. Isolate Neotyphodium from self-germinating wild D.sinense protocorm, at the beginning we could find few protocorm got infected by Neotyphhodium, only 13 of them, after being screened out, we got 5 with beneficial endophytic fungi.5. Seeds germinated after 2 mouth; protocorm enlarged more than 500μm long with production of rhizoids; seedling with a tuber developing at the growing apex after 3 mouth.