Study On Proliferation Of Protocorm-Like Bodies In Bioreactor Culture And Analysis On Effective Components Contents Of Dendrobium Candidum

Dendrobium candidum is one of the rare medicinal plant which has great value for drug. Because of the low rate of seed germinatio and slow speed of division propagation,influenced the process of scale production. In addition,the low transplanting survival rate caused the shortage of supple and demand. In this study,we studied factors affecting the rapid propagation of protocorm-like bodies (PLBs) of Dendrobium candidum.Several physical and chemical parameters of air lift bioreactor culture were also examined to explore optimization for PLBs proliferation and active components accumulation,which provide the theoretical basis for exploitation of Dendrobium candidum.The results demonstrated that the highest proliferation rate of PLBs was found in 1/2 MS; the 1/2 MS supplied with 0.5 mg·L-1 NAA and 2 mg·L-1 BA promoted PLBs proliferation growth; and the optimum PLBs proliferation and growth was determined in the medium of 1/2 MS+0.5 mg·L-1 NAA+2 mg·L-1 BA supplied with 100 ml·L-1 coconut juice.Air-lift bioreactors were used for large scale propagation of PLBs of Dendrobium candidum. In 3 L bioreactor, optimal inoculation density was 20 g, in which PLBs fresh weight reached 167.5 g and was clearly superior to 10 g and 30 g PLBs inoculated. In bioreactor,1600 Lux light intensity was considered to be the most effective light intensity for the proliferation of PLBs. In addition, air volume of 0.20 wm was good for proliferation of PLBs.Inoculation density,light intensity and air volume all affected on polysaccharide and alkaloid contents of PLBs Dendrobium candidum. Polysaccharide content was higher when inoculated 10 g PLBs,and the alkaloid content was higher when inoculated 20 g.In different light intensity,the sequence of polysaccharide contents was 2400 Lux> 1600 Lux> dark, but alkaloid accumulation was just opposite.0.2 vvm air volume was the best for polysaccharide and alkaloid accumulation.The contents of both polysaccharides and alkaloid rised during 10 days to 30 days and the polysaccharides and alkaloid yields reached peak after thirty days cultivate. Then the contents of both polysaccharides and alkaloid had decreased.The polysaccharide and alkaloid contents of PLBs were 214.18 mg·g-1 and 3.78 mg·g-1,and they were higher than cultivation shoots and tissue culture seedling,and tissue culture seedling was the lowest.