Plant Regeneration by in vitro Tissue Culture in Platycodon grandifrolum
Background : Platycodon grandiflorum has been used as food material and a traditional medicine in Korea. In order to develop an efficient in vitro micropropagation technique for a rare plant species and conservation for inbred line of plant breeding. Methods and Results : Plant regeneration via organogenesis and somatic embryogenesis was investigated in Platycodon grandiflorum. Leaf, stem, root tissues of 7-day-old seedlings were cultured on 1/2MS medium containing various concentration (0, 0.5, 1 and 2 ㎎/L) of IBA, BA and NAA. The results showed that 1/2MS medium supplemented with BA+NAA 2.0 ㎎/L yielded the highest callus formation ratio of 73.5%. When various tissues (leaf, stem, root) were tested on 1/2MS medium containing BA 2.0 ㎎/L+ NAA 2.0 ㎎/L for somatic embryogenesis, the optimum tissue for embryogenic shoot induction was stem tissue. Callus were cultured on MS medium containing various concentration (0, 0.5 and 1 ㎎/L) of BA and NAA. The best rooting rate was achieved by three different medium (B5, 1/2MS and MS) and 1/2MS medium cultured the highest rooting ratio (82%). Conclusion : This study suggested that above micropropagation techniques can be used for rapid multiplication as well as in vitro or in vivo conservation of the Platycodon species.