Effects Of Fungal Elicitors On Protocorm Of Dendrobium Candidum

Dedrobium candidum, a orchidaceous plant used as a herb medicine to treat sore throat and eye diseases in China, had been ranked in the Catalog of Chinese Wild Endangered Plants. So, the protocorm which is a kind of tissue cultures from D.candidum was studied and applied as the substitute of medicinal D. candidum recently. Some fungal elicitors can enhance the contents of some activity compounds in tissue cultural material. This thesis is trying to explore the effects of fungal elicitors on the protocorm of D. candidum.Twenty four species of fungi (h1~h24) isolated from wild Orchidaceae plants were used as elicitors to treat the protocorm cultured in liquid medium (67-V). Of them, h10 was useful to increase the production of the protocorm and other fungi had no the effect. h24 enhanced the ability of protocorm to promote the multiplication of T lymphocytes of chicken and to inhibit the growth of tumor cells. The fungus h24 was identified as Mycena sp. in Basidiomycetes by analyzing its morphologic character and ITS sequence in rDNA.The content of total alkaloid of protocorm of D. candidum was enhanced more 58.2% than the control after elicitor was applied. Seven new chromatogram ingredients were detected in protocorm of D.candium treated with fungal elicitor than untreated protocorm by the reversed-phase HPLC method, and three of them were the same as wild D.candidum.A protocol of solid-liquid cyclic culturing method was established to quickly propagate the protocorms of D. cadidum, in which every step was studied to find the appropriate medium. The half-strength MS-based medium containing 20% potato extracts, 3% sucrose and 9% agar was proved to be helpful to the growth of protocorms in solid medium. It is necessary to the growth of protocorm adding potato extract in medium and the seedling differentiation of protocorms by BAP. The phytohormone NAA also increased the production of protocorms. Adding Fungal extracts in medium and pH6.0 could inhibit the growth of protocorm. The protocorms cultured in liquid medium (67-V) have good quality and grew quickly. In 67-V, MS, 1/2MS, 1/2 total MS solid medium, the 1/2 total MS was the best medium for transplanting the protocorms from liquid medium to solid medium.Several protocorm lines with special characters were selected for the study on elicitor experiments. The line B and Hp6 had high content of total alkaloid and G was sensitive to the...