Study On Isolation And Identification Of Orchid Mycorrhizal Fungi And The Symbiotic Relationship Between Mycorrhizal Fungi And Cymbidium

Orchidaceae is one of the largest families of angiosperms, and it is very famous for its ornamental and medicinal values. Orchids have to rely on the formation of a stable symbiotic relationship with mycorrhizal fungi to complete the normal life cycle. The symbiotic relationship between Orchid and mycorrhizal fungi are specific or diverse have been always controversial. The cultured methods of mycorrhizal fungi can be targeted to collect orchid mycorrhizal fungi. The uncultured methods in the mycorrhizal fungi study can help to solve the difficulties of mycorrhizal fungi separation and identification. The mycorrhizal fungi study of different types and different regions Orchid plants, for determining symbiotic relationship between orchid and mycorrhizal fungi provide new evidence. The major findings are as follows:1,With the cultured methods, a kind of mycorrhizal fungi was isolated from Sichuan Jiangjin Cymbidium lancifolium. Preliminary identification of the fungi as the Ceratobas-idium; another kind of mycorrhizal fungi was also isolated from the Sichuan Jiangjin C. kanran, and it was preliminary identificated as the Tulasnella.2,Primers ITS1-OF/ITS4-OF, T2/ITS4, ITS1/ITS4-Tul, CeTh1/CeTh4 and S1/ITS4 all can be used for the uncultured study of mycorrhizal fungi. Using the uncultured meth-ods with universal primers T2/ITS4 to study the infection rate of Zhejiang Orchid Mycorrhizal, products of PCR with primers T2/ITS4 were sequenced and analyed. The results indicated that all these ITS sequences had highly homology with the Tulasnella's rDNA, and the infection rate was 50.79%.3,Cultured methods were carried out to analysis the mycorrhizal fungi of the rhizomorph from Henan Xinyang Orchid,and fifteen different endophytic fungus strains were isolated from three C. faberi, and seventeen endophytic fungus strains were isolated from four C. goeringii. All of the experiments did not obtain common mycorrhizal fungi.4,Using universal Basidiomycetes primers ITS1-OF/ITS4-OF, RFLP and sequen-cing methods to study the diversity of endophytic basidiomycetes fungi in orchid roots and rhizomes from Henan Xinyang, from the rhizome of C. faberi we only got Sebacina mycorrhizal fungi, but from the roots of C. faberi we got four different species of endophytic fungus; from the rhizome of C. goeringii we only isolated Sebacina mycorrhizal fungi, and from the roots of C. goeringii we isolated eight different species of endophytic fungus, including Sebacina mycorrhizal fungi.5,Uncultured methods were carried out in orchid plants to study mycorrhizal fungi. These plants came from Hubei, Zhejiang Tianmu Mountain, Chongqing Jinfo Mountain, Fujian Wuyi Mountain, Henan Xinyang. It found that C. faberi and C. goeringii from Tianmu Mountain in Zhejiang and Jinfo Mountain in Fujian, and C. goeringii from Hubei had the same symbiotic fungi, Tulasnella; only C. goeringii and C. faberi from Henan Xinyang symbioted with Sebacina. It indicated that most of C. goeringii and C. faberi from different districts symbioted with Tulasnella, and only a few areas of that symbioted with Sebacina. It displayed that symbiotic relationship had a significant specificity at the level of genera.