Study On Cultivating Seedling Of Cymbidium Insigne Rolfe With Mycorrhizal Fungi

As an important plant resource, the Orchidaceae has huge economical and medical value with huge market. However, wild orchid resources were decreasing and suffering serious destruction because of the official and ornamemental demand. In order to explore the function of Orchidaceae mycorrhizal fungi, improve the survival and growth rate of orchid plants, fungal strains were isolated from natural roots of Cymbidium goeringii and Doritis pulcherrima and inoculated into Cymbidium insigne. Under tissue culture condition, some good strains can promote the growth of orchids significantly. By using indicators such as mycorrhizae coloration, fungi re-isolation, growth of biomass, etc., it is confimed that a symbioses culture systerm was established between fungi and orchids. The main results are summarized as following:(1)Screened the optimum medium for strengthening seedling and rooting of C. insigne. C. insigne tissue culture seedlings were cultured in different media before transplanting. The result showed that the seedlings in vitro with 1/2MS + NAA 2.5 mg·L^-1 + IBA 0.5 mg·L^-1 + agar 8 g·L^-1 + sucrose 20 g·L^-1 + active carbon 1 g·L^-1 +banana10 g·L^-1 grew better and had more roots; the average increasing ratio of root to shoot is 55%, the leaf to shoot is 133.3%, the ratio root and bud to shoot is 47%.(2)Selected the unconfronted combination of fungi. The fungi isolated from Cymbidium goeringii and Doritis pulcherrima Lindl are symbiotic cultured. It was found that combination of DMF80+CF1,DMF80+CF2,DMF80+CF3,DMF80+DHL19 are the fusion ones.(3) Screened the strains combination which can promote the growth of C. insigne. Estalised co-culture relationship between mycorrhizal fungi and C. insigne, By measuring the rate of fresh weight and chlorophyll of C. insigne after 60 days, the results showed that combination of CF2+DMF80 can promote the growth of orchid seedlings significantly. (4) Through transplanted the C. insigne seedlings into the different mixed substrates and then compared the survival rate and growth vigor, the optimum medium was obtained. It resulted that the survival rate of seedlings transplanted with Turfy soil and perlite (2:1) is 92%, which indicated this combination is ideal for transplanting.(5) After compared the effects of pH, temperature and Vitamins to the strain DMF80, it indicated that the strain DMF80 can grow better in pH 8.0 with a little nicotinic acid in 30℃.