ABSTRACT
The present work describes a procedure that allows for the easy and rapid induction of somatic embryos, calli, shoots and adventitious roots of Vietnamese ginseng (Panax vietnamensis Ha et Grushv.) from longitudinal thin cell layers (lTCLs). In order to investigate the morphogenesis of this medicinal plant, the effect of separately–supplemented plant growth regulators and combinatorial effect of co–supplemented auxins and cytokinins in dark or under 16-hour photoperiod was examined. After eight weeks of culture, the lTCL explants excised from petiole of three-month-old in vitro plants and cultured on a semi solid basal Murashige and Skoog (MS) media supplemented with 1.0 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.1 mg/l thidiazuron (TDZ) in dark, 2.0 mg/l α-napththaleneacetic acid (NAA) in dark and 1.0 mg/l 2,4-D under light gave the highest rate of callogenesis (100%), embryogenesis (53.3%) and adventitious root formation (100% with a mean of 16.7 roots), and shoot formation (26.7%), respectively. The metabolite of petiole lTCL-derived calli qualitative and quantitative analyses were performed by using high-performance liquid chromatography and thin layer chromatography. The simple procedure, together with similar saponin profiles between the resulted in vitro tissues and plants grown in nature, suggest its potential use in generating Vietnamese ginseng in large amount for medicinal purpose.