[Fluid suspension co-culture of Dendrobium officinale protocorm and living fungus].

OBJECTIVE: To set up a system for fluid suspension co-culture of Dendrobium officinale protocorm and living fungus MF24, so as to provide certain scientific evidence for industrial production of protocorm. METHOD: Whether the protocorm culture system was suitable for the normal growth of MF24 fungus were studied, the growth of protocorm cultured alone and co-cultured with the fungus were researched under light and dark culture conditions, the biomass and proliferation times were determined, and HPLC method was used to analyze and compare the changes of 11 characteristic peak areas in D. officinale protocorm. RESULT: The MF24 fungus could grow normally in the 6,7-V liquid medium used to culture the protocorm, and when it was cultured by 8-10 hours per day under 1 500 lx, the growth rate of the fungus was slowed. Protocorm could grow normally in light and dark culture conditions, and add the MF24 fungus in the early cultivation stages of protocorm, both inhibit the growth of each other. In the protocorm for the growth stability to add 5 diameter 9 mm fungi block, the protocorm growth and chemical composition type had no significant effect. However, under illumination, co-cultured for 5 days protocorm of which 10 compounds content decreased 13.64% to 138.47%, in dark conditions, co-cultured for 5 days protocorm of which 7 compounds increased by 0.71% to 12.82%, and 4 compounds slightly reduced by 3.03% to 14. 14% compared with the control. CONCLUSION: Under the appropriate condition, living fungus MF24 could co-culture with the D. officinale protocorm, and affected the latter's secondary metabolite levels.

[Cultivation of protocorms of Dendrobium candidum in air-lift bioreactors].

OBJECTIVE: To explore the factors affecting the growth of protocorms of Dendrobium candidum and substance synthesis in a reactor, in order to provide a new method for mass production of raw materials of D. candidum. METHOD: Protocorms in vitro were used as experimental materials to study the effect of inoculum volume, light intensity and air volume on the growth of protocorms of D. candidum and the accumulation of polysaccharide and dendrobine in a 3 L-air lift balloon type bioreactor. RESULT: After 30 days of cultivation in a bioreactor, protocorms became dark green and grew well at the inoculum volume of 10 g x L(-1). The polysaccharide content in protocorms showed no difference at various inoculum volumes; whereas the dendrobine content showed differences (with the highest treatment at the inoculum volume of 10 g x L(-1)), particularly the productions of polysaccharide and alkaloid reached the maximum at the inoculum volume of 10 g x L(-1). The condition of 1 600 lx of light intensity was the most favorable for the growth of protocorms. Though light played a role of improving the accumulation of polysaccharide in protocorms of D. candidum, it could inhibit the accumulation of dendrobine. Polysaccharide content and production were better under light conditions of 1 600 and 2 400 lx than dark conditions. Despite the maximum dendrobine content in dark conditions, the dendrobine production showed the maximum in the light condition of 1 600 lx due to poor growth of protocorms. Protocorms grew well and became dark green at the air volume of 0.2 vvm (air volume culture volume per minute) , which was better than at 0.1 and 0.3, with maximum polysaccharide and dendrobine contents and productions. CONCLUSION: In a 3 L-air lift balloon type bioreactor with a working volume of 2 L, the conditions of 10 inoculum volume, 1 600 lx light intensity and 0.2 air volume were favorable for the growth of protocorms and the production of dendrobine. This demonstrates that the cultivation of D. candidum and substance synthesis in a reactor is an effectie approach for mass production of polysaccharide and dendrobine.

[Effects of light quality and germplasm on growth and effective ingredients of Dendrobium officinale germchit].

Effects of light quality and germplasm on the growth and effective ingredients of Dendrobium officinale germchit were studied. Under 8 light qualities (red, blue, yellow, green and three different red blue mix light), test-tube plantlets of different families (9 x 66, 17 x 30, 78 x 68) were used in the experiment to measure economical character and determine the content of chlorophyll, polysaccharides and total alkaloids. The results showed that light quality, germplasm and their interaction had a significant effect on the growth of D. officinale germchit. The maximal root length and height of seedling were obtained under red light, under blue light, the stem diameter was thickest and the content of total alkaloids were highest, the content of chlorophyll and polysaccharides of test-tube plantlets under red blue mix light were higher than that of other treatments. This work has laid a foundation for the high quality, low carbon and efficient production of D. officinale, and gives useful tips on production of high quality ingredients.

Enhancement of the differentiation of protocorm-like bodies of Dendrobium officinale to shoots by ultrasound treatment.

An efficient micropropagation protocol has been developed for Dendrobium officinale, through protocorm-like bodies (PLBs). A correlation between enhanced differentiation of PLBs of D. officinale by ultrasound and changes in the levels of endogenous hormones and the antioxidant enzyme activities was described. Ultrasound treatments improved the conversion of PLBs of D. officinale to shoots. The highest conversion frequency of PLBs to shoots was obtained following the ultrasound treatment at 300 W for 5 min. Compared to the control, the enhanced conversion of PLBs to shoots following the ultrasound treatment was accompanied by an increase in the ratio of total cytokinins (CTKs) to indole-3-acetic acid (IAA), which was due to a decrease in the endogenous level of IAA and an increase in the endogenous level of total CTKs. Analysis of enzyme activities indicated that the increased endogenous level of total CTKs driven by ultrasound was associated with the inhibition of CTK decomposition by CTK oxidase (EC 1.4.3.6), while the decreased endogenous level of IAA was associated with the promotion of IAA decomposition by IAA oxidase (EC 1.10.3.3). In addition, ultrasound treatment increased the activities of superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6) and peroxidase (EC 1.11.1.7) in the conversion process of PLBs to shoots.