Research On Optimization Of Tissue Culture And Rapid Propagation Technology Of Dendrobium Candidum

Dendrobium offinale Kimura et Migo is not only a valuable medicinal plant,but also a kind of very rare ornamental plant.For thousands of years,it has been listed as top grade traditional Chinese medicine(TCM)with ginseng,ganodorma lucidum,cordyceps sinensis and other medicinal plants,and it’s ranked first place in the nine of the most famous medicinal plants.D.officinale suffered excessive excavation of human in recent years because of its very high medicinal value and economic value,and its resource is on the verge of extinction.In order to protect the rare traditional Chinese medicine and also for the development of artificial cultivation to satisfy the market demand,D.officinale has become the focus in the study of plant tissue culture and rapid propagation.This research focuses on three aspects as follows:The optimization of culture medium in PLBs proliferation;The optimization of culture medium in rooting stage;Set up D.ofcinale’s hormone-free cultivation system.The above research can provides theoretic and technical support for large-scale and factory period in the future.With the PLBs induced from the seeds of D.officinale as the experimental materials,the effects of different basic mediums and ABA concentration on the PLBs proliferation were studied.Then the optimal concentration formula of NAA,6-BA and ABA was screened by orthogonal test.And the optimal medium ingredients for PLBs proliferation of D.officinale was:1/2MS medium+0.2 mg/L NAA+1.0 mg/L 6-BA+0.2 mg/L ABA,meanwhile supplemented with sugar 30.0 g/L,potato extract 100.0 g/L and agar 6.0 g/L.With the D.officinale seedlings which in the strong seedling growth phase as the experimental materials.Designed of different modified 1/2MS basic medium which have different amount of nitrogen and different ratio of NH4+ to NO3-to explore the optimal basic medium for D.officinale seedlings growth.Then the best strong seedling and rooting medium was selected according to orthogonal test.Results showed that the suitable nitrogen concentration for growth was 40 mmol/L,the best ratio of NH4+ to NO3-was 1:3.And the optimal medium ingredients was:modified 1/2MS medium +80.0 g/L potato extract+80.0 g/L banana extract+1.5 g/L activated carbon,meanwhile supplemented with NAA 0.4 mg/L,IBA 0.4 mg/L,sugar 30.0g/L and agar 7.0 g/L.With the PLBs induced from the seeds of D.officinale as the experimental materials,we studied the effects of hormone-free medium on the PLBs proliferation and differentiation and the growth of D.officinale seedlings.In the PLBs proliferation and differentiation stage,selected different kind and concentration of additives was the first step according to orthogonal test and then different basic medium was used to filter the best medium for proliferation and differentiation.But in the strong seedling and rooting stage,the basic medium was carried out first and then we selected different kind and concentration of additives by using orthogonal test.The hormone-free cultivation system that we found was:modified 1/2MS medium+100.0 g/L coconut extract+60.0 g/L potato extract+1.0 g/L peptone,meanwhile supplemented with sugar 30.0 g/L and agar 6.5 g/L(PLBs proliferation and differentiation stage);1/2MS medium+ 1.0g Hyponex no.1+80.0 g/L potato extract+80.0 g/L banana extract+1.0 g/L peptone+1.5 g/L activated carbon,meanwhile supplemented with sugar 30.0 g/L and agar 7.0 g/L(strong seedling and rooting stage).