Nobile Dendrobium In Vitro Micropropagation System Optimization And In Vitro Flowering Exploration

As one of the four ornamental Orchids, Dendrobium has the important ornamental value and broad market prospects. In recent years,with the demand growing, The Tissue Culture technology is necessary for factory production.Nobile type Dendrobium was used as test material in this experiment to optimize the important part of Rapid Propagation System and study vitro flowering.In this process, the protocorm were observed.This study aims to provide a theoretical basis for Nobile type Dendrobium’s industrialized breeding and in vitro flowering.The main results are as follows:(1)Use Young pseudobulb as explants could induced axillary bud, horizontal induction better than upright, MS+NAA0.2mg/L of+6-BA3mg/L has the best effect.(2)multiple shoots induced by Axillary buds is proliferating. auxin NAA has the better effect than2,4-D.TDZ better than6-BA.The most suitable medium is MS+TDZ0.01mg/L+NAA0.1mg/L.(3)Apical, shoot tips and young leaves of tissue culture was used as explants for PLB induction,found that young leaves can not induced the Protocorm, shoot tip and root tip both can induced the Protocorm.Shoot tip has the best result,it’s Induction rate reached80%.(4)The plant hormone KT plays a very significant role in promoting the original bulbs’induction. Use shoot tips as the explants, medium of MS of+TDZ0.02mg/L+NAA0.2mg/L+KT1mg/L has the highest induction rate.(5)Medium of MS+TDZ0.005mg/L+2.4-D0.5mg/L+KT0.5mg/L has the best effect for the Proliferation and differentiation of Protocorm.The Protocorm and adventitious buds in this medium is green and growth well.(6)Observed the Protocorm and the process of proliferation and differentiation, found the shoot tip can induced mixed clumps which contain Callus, Protocorm and Adventitious buds. It’s cells have strong proliferative capacity.(7)Axillary buds can produced flower buds with high concentrations of6-BA and suitable NAA. Medium of MS+6-BA7.0mg/L+NAA0.2mg/L has the best effect,induced rate reached33.3%, but abortion was very serious, most of flower buds can not last flowering.(8)Axillary buds can also produced flower buds with high concentrations of TDZ and suitable NAA, and the effects are significantly better than the combination of6-BA and NAA.MS+TDZ0.15mg/L+NAA0.2mg/L has the best result,induced rate reached52.25%.although the flower buds can flowering,the flower is deformed,light colored and lack of floral organs.(9)Pretreatment with PP333can improve induction rate of flower buds,axillary buds on MS+PP3332mg/L to pretreat25d, then turned to MS+TDZ0.15mg/L+NAA0.2mg/L,can reached the highest rate of70%.(10)Pretreatment with ABA has little effect for induction rate of flower buds,axillary buds on MS+ABA3mg/L to pretreat25d and sub-access the medium of MS+TDZ0.15mg/L+NAA0.2mg/L to culture,the induction rate can reached56.7%.(11)To reduce the N/P can significantly improved flower bud’s induction rate, reduce the concentration of N to the original solution’s1/10and increase the P as5times as the original solution’s concentration would have the best effect,inducing rate reached65.57%.(12)The concentration of sucrose influenced in vitro flowering of Dendrobium nobile.When the concentration reached40g/L,the flowering time extended and induction rate of flower buds is highest.