Explant preparation affects culture initiation and regeneration of Panax ginseng and Panax quinquefolius

The influence of explant preparation on culture initiation and regeneration was investigated. Explant preparation was defined as the application of surface disinfection and homogenization to ginseng roots and embryos. Surface disinfection significantly affected culture initiation and subsequent embryogenesis. A high success rate (80–97%) in culture initiation was associated with explants from non-surface disinfected root tissue. The cumulative contamination rate after 8 months was below 4%; in contrast, a contamination rate of 85% was observed in disinfected root explants. For non-disinfected explants, visible callus was induced in 1 week, adventitious root and somatic embryos were formed in 2 and 6 months, respectively. Explants from disinfected roots required 1 month to induce visible callus, 5–7 months for adventitious roots and 10 months for somatic embryogenesis. For germinating embryos, disinfected embryos required double the time for embryogenesis than non-disinfected ones. It was considered that surface disinfection imposed a stress and subsequently a carry-over effect on explants.