Screening And Biological Characteristics Of Symbiotic Fungi From An Endemic Orchid In Hainan Island: Dendrobium Sinense

Orchidaceae is one of the largest families of Angiospermae, Many species have very high value in ornamental and medicinal. But, because a lot of reasons. Many wild orchids are confronted with exhausted, regarded as a flagship group in plant conservation, as well as Dendrobium sinense was included. Therefore, it is essential to research and conservation Orchidaceae from symbiotic fungi.In order to explore application of symbiotic fungi on propagation, cultivation and conservation of Dendrobium sinense, Endophytic fungi were isolated from protocorm of wild Dendrobium sinense. Screening beneficial symbiotic fungi of Dendrobium sinense by reinoculate fungi. And to discussed biological characteristics of symbiotic fungi from Dendrobium sinense. The main results and conclusions are summarized as the following:(1)Take Bio-indicators of plant growth and chlorophyll as screening indicators,five beneficial symbiotic fungi of Dendrobium sinense were screened, these fungi showed marked stimulating effects on growth, also increased chlorophyll. But, different strains have different effects, and the same strain have different growth stages of Dendrobium sinense.(2)The symbiosis culture system of mycorrhizal fungi and Dendrobium sinense were initial establishmented.The best symbiotic culture medium of mycorrhizal and Dendrobium sinense in vitro was:1/2MS+sugar7.5g/L+agar 12g/L, pH5.8.The MS and 1/2MS culture medium were added fungal elicitor are development on growth of the Dendrobium sinense protocorms. The 200ml/L fungal elicitor was more conducive to growth of Dendrobium sinense protocorms. Can stimulate growth of Dendrobium sinense by fertilize liquid fungal inoculum. This method is simple, low cost, can be applied to artificial cultivation of Dendrobium sinense.(3)The optimum temperature is 25℃of Dendrobium sinense symbiotic fungi, Suitable growth temperature between 5～40℃, the lowest growth temperature of 5～15℃, the highest growth temperature of 30～40℃, when the temperature is≤5℃or≥40℃, the fungus were stop grow.The symbiotic fungi grow better on rich organic nutrient of PDA and OMA culture medium.Symbiotic fungi of Dendrobium sinense have wider range of carbon sources, can make use of monosacharides, disaccharides, polysaccharides and other carbon sources; Using maltose, soluble starch, carboxymethyl cellulose, sucrose were better, but use of sorbitol was poor; The lack of carbon sources was not significantly inhibited growth of symbiotic fungi. Symbiotic fungi of Dendrobium sinense used of yeast extract, peptone, glycine, sodium nitrate were better, but the poor use of sorbitol; The strains have their own advantages nitrogen sources, individual strains has specific requirements for nitrogen; In addition to S12 strain, other strain growth was inhibited when nitrogen-free.Symbiotic fungi of Dendrobium sinense were shown a relatively strong phosphate-solubilizing ability. And the phosphate-dissolving capacity and decrease culture medium pH is closely related, within a certain range, phosphate-solubilizing ability decreased with the culture medium pH, while the enhanced medium phosphorus content. Phospho r-rus content of medium, phosphorus content of mycelium and pH was significantly ne-gative correlation.