Effect of polyploidy induction on biomass and ginsenoside accumulations in adventitious roots of ginseng

Abstract

Adventitious roots of Panax ginseng C.A. Meyer (a natural tetraploid) were treated with 50 or 100 mg L-1 colchicine for 12, 24, 36, 48, or 60 h to induce polyploid (octoploid) roots. The largest number of octoploid roots was obtained with a 100 mg L-1 colchicine treatment over 60 h. To verify that ginsenoside was being accumulated in the developing tissues, the tetraploid (control) and octoploid roots were cultured for 40 d in Murashige and Skoog media that lacked NH4NO3 but was supplemented with 2 mg L-1 naphthaleneacetic acid and 50 g L-1 sucrose. Levels of fresh and dry biomass were greater in the octoploid roots. Although total ginsenoside and Rb-group ginsenoside contents were less in the octoploid roots than in the tetraploids, the former had a higher amount of Rg-group ginsenosides (especially Rg1). These results demonstrate the benefit that polyploid adventitious roots provide in enhancing the production of secondary metabolites in ginseng.