Screening And Functional Characterization Of Endophytic Mycorrhizal Fungus In Dendrobium Officinale

Dendrobium officinale belongs to a perennial herbaceous plant,it is also a traditional rare Chinese medicine.Many researches showed that mycorrhiza fungus have obvious function of promoting plant growth and resistance to adverse environment;however,there is no special biological fertilizer of D.officinale in China yet.In this study,We mainly showed the screening of mycorrhiza fungus,artificial culture,agent preparation as well as functional effectiveness and mechanism.We have screened some good mycorrhiza fungus and prepared special agent of them,and laying a foundation for the organic cultivation of D.officinale.The main results were summarized as follows:1.Eight species mycorrhiza fungus from D.officinale root were screened by artificial cultivation test,among of which Fusarium oxysporum and Umbelopsis dimorpha are excellent mycorrhiza fungus.A suitable solid agent formula is composed of beef extract,fish peptone and ammonium nitrate as exogenous nitrogen source;Condition of culture is 25? 12 h light + 12 h dark,pH6.5.2.Confirming the method of inducing D.officinale planting seedlings formatting mycorrhiza.The agent was inoculated on the cultivation substrate surface of D.officinale seedlings,inoculated approximately five gram one cluster.Effectiveness of inoculating sold agent is the better than liquid agent.3.A preliminary study of promoting growth and resistance diseases mechanism for D.officinale mycorrhiza was carried out on.the physiological and biochemical level.The results showed that mycorrhizal fungus can improve plant absorption function for phosphorus,potassium,calcium and other mineral elements,also it can increase the chlorophyll content of the plants,contributing to the growth of plants.Mycorrhizal fungus can also improve the activity of the superoxide dismutase,peroxidase,polyphenol oxidase,phenylalanin ammo-nialyase,as well as to enhance the resistance ability.