| Cymbidium, the most important orchids in commerce, consists of 48 species in China as many as 70 species in the word. Orchids are ubiquitous, they are divided into 3 types by their habitats:(1) Terrestrial Orchid:they live in the environment of fertile and loose soil. (2) Epiphytic Orchid:they epiphytic on rocks or precipice. (3) Epiphytic or Terrestrial Orchid:they grow under the plants or bushes the place with rich humus.All Cymbidium plants have an obligate relationship with mycorrhizal symbionts in the condition of usual growing. Due to the mycorrhizal fungi is very important for orchids, the study on diversity of endophytic fungi from orchids received more attention. Know well the diversity of endophytic fungi of orchids is very significative for orchid conservation and industrialization development.In total,10 mycorrhizas of Cymbidium plants were sampled, which from the provinces of Guangxi, Hunan, Guizhou and Yunnan, include C. goeringii, C. kanran, C. cyperifolium, C. lancifolium, C. floribundum, C. bicolor, C. tracyanum, C. ensifolium, C. qiubeiense and C. lanpan. We used both traditional tissue segments culture method and molecular method to investigate the compositions and seasonal changes of endophytic fungal within Cymbidium roots. In order to evaluate the effect of endophytic fungal isolates on seed germination, Cymbidium orchid seeds were inoculated with fungal strains isolated from adult orchids. The primary results are as follows:1. Fungal endophytes were abundant and diverse in healthy plant roots of Cymbidium. A total of 134 culturable endophytes were isolated from 15 fresh root samples. The isolated strains were identified into 32 genera. They belong to Fusarium, Ceratorhiza, Chaetomium, Papulospora, Aspergillus, Penicillium, Alternaria, Xylaria, Cylindrocarpon, Phomopsis, Trichoderma, Epulorhiza, Leptosphaeria, Tulasnella, Monilia, Acremonium, Didymopsis, Podospora, Paecilomyces, Fusoma, Nigrospora, Bionectria, Chromosporium, Sclerotium, Dactylella, Colletotrichum, Diaporthe, Sebacima, Cochliobolus, Arthrinium, Nodulisporium, Glomerella. Among them,15.7% were classified into 7 genera, and 84.3% were mycelia sterile. The regnant group consisted of members of the anamorph genus Fusarium (25.74%), Xylaria (7.35%), Cylindrocarpon (6.62%), Phomopsis (4.14%), Epulothiza (2.947%) and Tulasnella (2.94%). All of these cultured endophytes belong to Ascomycota and Basidiomycote, and the Ascomycota was dominant, containing 28 species.2. The elicitor made from 16 species of endophytic fungi will be a culture medium to induce the tissue cultures of Cymbidium goeringii. Compared to CK, the inducing effects of CF1, CF10, CF11, CF12, CF15 and CF16 did the best in biomass increasing, and the weight getting heavy extremely. The inducing effects of CF10, CF11, CF12, CF15 and CF16 did the best in differentiation of adventitious bud. Additionally, the weight of tissue culture that wereâ… =10g/L,â…¡=15g/L,â…¢=20g/L (â… <â…¡<â…¢) increased with adding fungal elicitor of CF1, CF10, CF11, CF12, CF15 and CF16. The weight had significant difference compared with those in control when it added to concertration of III. Meanwhile, based on two forms fungal elicitors with liquid and powder were added to the tissue cultures of Cymbidium goeringii, the result was that liquid elicitor was better than the elicitor made of powder.3.612 tissue culture seedlings of the Cymbidium goeringii were inoculated with 16 different fungal strains. About three months later, the seedings inoculated with strains CF1, CF2, CF11, CF15 and CF16 had significantly increased the fresh weight, the new roots became more, stronger and larger compared to the control, the same as the stem of seedings. In addition, the five strains were obtained by re-isolating. Pelotons, regarded as typical structures of orchid mycorrhizae, were also found in the inoculating roots under a microscope. It seems that the strains of CF1, CF2, CF11, CF15 and CF16 were associated with the Cymbidium goeringii and supplied the orchid with nutrition.4. It belonged to the typical mycorrhiza of orchids though the observation of the mycorrhizal microstructure of Cymbidium goeringii. The fungi entered the cortical tissue by breaking the velamen after the invasion of the fungi into the velamen. The pelotons were irregularly distributed in the cortex, mainly in outer cortical cells. Pelotons often occurred near the nucleus and twisted together in the infected cortical cells. The hyphae penetrated through the wall of cortical cells and then continuously spread inwards. Fresh pelotons and deformed pelotons in the cortical cells occurred simultaneously, and when they are digested and absorbed the hyphae provide nutrients to plants.5. As the results of the research on seed germination show that a part of seeds from Cymbidium lancifolium and Cymbidium cyperifolium with the 16 isoated fungi in dark can germinate after 3 months. Seeds of Cymbidium cyperifolium got high viability according to TTC staining examination. Most of the embryo seeds germinated swelled, or few of them developed radical hairs. The results showed that seed germination rate related to orchid mycorrhizal specificity more than seed viability. And the results of seed germination in situ was not ideal, the condition needed to be further exploration and researching.
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