Studies On The Critical Techniques Of Dendrobium Candidum Protocorm-like Bodies Suspension Culture In Large-Scale

Dendrobium candidum, genus of Dendrobium, family of Orchidaceae, is a perennial epiphytic herb. It has long been used as a rare traditional Chinese medicinal material in China medicine; polysaccharides were identified as its major pharmaceutical active ingredient of Dendrobium candidum herb. Because of excessive collection, destroy of habitant environment and low reproduction rate, the population of wild resources of Dendrobium Candidum declined drastically recently. To meet the growing demands for raw material of Dendrobium Candidum, it’s necessary to produce Dendrobium candidum artificially. As the physiol-biochemical metabolism and morphological development potential of Dendrobium candidum protocorm-like bodies (PLBs) is similar with the original plant, and more important, could grow quickly, the large-scale cultivation of the PLBs is a feasible pathway to solve the shortage of Dendrobium candidum resources. The Dendrobium candidum seed-derived PLBs were sampled for examining its growth difference between two culture modes of suspension cultures and shaking culture, and furthermore for preliminary experiment of scale-up culture, as well as the key factors affecting PLBs growth, including illumination, temperature, sugar concentration and CO2 concentration, were also investigated, and finally, the questions involving in the large-scale culture of PLBs were discussed in the end of this text. The main results are as follows:1.The growth rate of PLBs in suspension cultures was lower than that in shaking culture and the PLBs was in yellow color. When the PLBs weren’t covered by the liquid culture media completely, it could grow uniformly and in bright green color.2.1n scale-up culture, after twice addition of fresh medium, PLBs could gain best growth trend, with the prolonging of time, and it grew slowly, brown and dead.3.Subjected to illumination of 20001x, the accumulation of polysaccharide got to its peak of 23.4%, however, stronger or weaker than 20001x, both couldn’t gain better polysaccharides accumulation; as to the growth temperature, it’s determined to be the favorable temperature of 25 ℃; supplemented with 20g/L sugar in media, an increment index of 1.52 was achieved under 110r/min, however, addition of lOg/L sugar would be better if the shaking speed was decreased to 70r/min, and its increment index was 1.48; if the PLBs was provided with proper CO2, it would be beneficial to its growth.4. The first step was to determine the production scale in the process of large scale production of PLBs, and then the design of production shop, and finally to build other matching establishments. The major problems in scale-up culture are pollution, browning and etiolation.5. The bioreactor favoring for the large-scale culture of Dendrobium PLBs was designed on the base of the growth conditions parameters, which would provide technical support for the subsequent large-scale culture of Dendrobium PLBs.