Study On Rapid Propagation And Total Alkaloids Accumulation Of Dendrobium Nobile

Tissue culture, rapid propagation and cultivation of Dendrobium nobile Lindlliving in Guizhou province were studied. In addition, Dendrobine, an activecompoments, was used as a standard to determine the quality of D. nobile in thewhole procedure of cultivation from protocorms to mature plants. The main resultsare as follows. 1. The rapid propagation of D. nobile has been accomplished by means of bothseed culture and embryo culture. Higher germinating rate and survival rate wereobtained when the hormone-free MS(1/2 ME, major element)medium was used as basicmedium in the condition of 5.6⁵.8 of pH value, 1000²000lx of lumination,12h/dof light duration, and 25±2℃ of temperature. The protocorms kept a very longperiod before they grew into seedlings. Because plants were easily obtained withinhalf of one year, it proved that this method is suitable for propagating Chinesemedical herbal Shihu (D. nobile). 2. There were three kinds of asexual propagations for D. nobile. They werecallus pathway, PLB (protocorm-like bodies) pathway and polyshoot (multipleshoots) pathway. Callus was induced from protocorm and could multiply itself bysolid or liquid culture. Every callus might differentiate into about thirty sprouts.PLBs came from sprout, polyshoots or protocorms. 3. The optimal solid medium for inducing buds was MS_{(1/2 ME)} with 2.0mg/L6-BA and 0.2mg/L NAA, and that for multiplying seedlings was MS_{(1/2 ME)} with1.0mg/L 6-BA and 0.1mg/L NAA. In addition, that for growing seedlings was MS_(1/2ME) with 0.5mg/L 6-BA and 0.1mg/L NAA, and that for inducing roots was MS_{(1/2 ME)}with 0.5mg/L NAA. 4. Both the type and concentration of plant hormones are able to regulate thedifferentiation of organs of D. nobile. 6-BA improved differiation of buds andformation of longer and more leaves, but it inhibited rooting, even led roots to dead.NAA and IBA prompted growth of roots, increased numbers and length and diameterof roots. 2,4-D could increase length and diameter of stems and width of leaves. Italso induced formation of flower buds in polyshoots. 5. Light, temperature and water are important factors for growth of PLBs andseedlings. When seeds were germinated in dark, protocorms and seedlings wereyellow. Lighting was benefit for formation of leaves, however, more lighting wasunfit for growth of D.nobile. The temperature between 25±2℃ was good forgrowth of seedlings. Dry medium led protocorms and seedlings to shrink and die. 6. The survival rate of tube plants of D. nobile from seeds relates to soil andmanagement in field. Seedbed was sawdust where was above rubble of limestoneand covered by 0.5¹cm moss. Keeping shadow and wet,seedlings generated newbuds and roots in a month.They lived and grew well and all of the length, diameter,thickness, hight, biomass of stems and leaves and roots were better than thosecultivated only in tubes or greenhouse. The survival rate was beyond 95%. Soilingsof N, P and K improved the output of stem of D. nobile. 7. The contents of alkaloids changed little between seedlings planted in tubesand those transplanted in the simular environment of wildings. Alkaloidsaccumulated in the process of growth, so it is pratical and achievable that tubeseedlings are used in cultivation instead of the nature plants. The content of alkaloidsin the polyshoots without rooting was 0.15%, and it was 0.01% in the protocorms.The content of alkaloids in leaves was higher than that both in stems and in roots. 8. D. nobile were transplanted by means of tube seedlings from Chishui that istheir provenance to Xingyi, both in Guizhou province, China. Results showed thatinsects were harmful to seeldings, but the effective compoments of alkaloids wereequel.