Specificity Relation Between Orchidaceae And Symbiotic Fungi Of Orchid Mycorrhizal

Ocrhidaceae is one of the largest families in higher plants. There are so many scientists who are interesting in Orchid mycorrhizal for its vital function of the natural growth of Ocrhidaceae. The specificity relation between orchids and their symbiotic fungi has always been a research hot spot in orchid mycorrhizal study fields while domestic research work in this area is unsystematic. This study has isolated mycorrhizal fungi from typical Orchidaceae of China, identified them both by traditional classification method of morphology and rDNA ITS sequence analysis of molecular biology techniques and studied the specificity relation between orchids and their symbiotic fungi preliminarily. Results are as follows:1.513 mycorrhizal fungi has isolated from 47 orchids of different distributions and different species. All stains have identified as generalized Rhizoctonia fungi according to traditional classification method of morphology.2. Mycorrhizal fungi which has isolated from Changnienia amoena and Tangtsinia nanchuanica is identified as Tulasnella by both traditional classification method of morphology and rDNA ITS sequence analysis of molecular biology techniques.3. rDNA internal transcribed spacer (rDNA ITS) analysis has used to find the diversity among 159 mycorrhizal fungi which has isolated from Cymbidium goeringii, Cymbidium fabei, Changnienia amoena and Tangtsinia nanchuanica in Zhejiang, Hubei and Anhui Province and preparatory research about the specificity relationship between mycorrhizae and orchids has made based on rDNA ITS analysis.(1) Tulasnella might be the most general species which can develop symbiosis relationship with terrestrial orchids.(2) Mycorrhizal fungi which has isolated from Cymbidium goeringii, Cymbidium fabei in Zhejiang Province have an obviously corresponding symbiotic species specificity relationship.(3) Cymbidium goeringii and their mycorrhizal fungi have an obviously correspondingly symbiotic specificity relationship influenced by the site where orchids distribut.(4) There is a rich diversity among mycorrhizal fungi which were isolated from the same root of Cymbidium faberi.