정금나무(Vaccinium oldhamii Miq.)의 다신초 유도 및 기외발근을 통한 식물체 재분화

Plant regeneration through multiple-shoot induction and ex vitro rooting in Vaccinium oldhamii Miq.

In vitro techniques were developed for propagating Vaccinium oldhamii using shoots with apical buds. Explants having an apical bud were cultured on Murashige and Skoog (MS) medium supplemented with 1.0, 2.0, and 5.0 mg/L of each zeatin, thidiazuron, 6-benzylaminopurine (BA), and 6-(γ,γ-dimethylallylamino)purine (2-iP) in order to induce multiple shoots. Among the tested treatments, the 2.0 mg/L of 2-iP proved to be most suited for the multiplication and growth of shoots; the multiple shoot induction rate was 100.0%, the average number of shoots was 7.4 per explant, and the average shoot length was 51.7 mm. The in vitro elongated shoots were rooted on half-strength MS medium containing various concentrations of indole-3-butyric acid (IBA) and 1-naphthaleneacetic acid (NAA). However, overall callus overgrowth was observed in all treatments and resulted in necrosis and abnormal shoot growth in root formation. A low concentration (0.5 mg/L) of IBA was appropriate for normal root development and the in vitro rooting rate was 30%. Ex vitro treatments on root formation using various concentrations of IBA with Talc powder and two types of rooting substrates (Flexi-Plugs or Horticultural soil) were examined. The ex vitro rooting rate (80%) and length of roots (32.9 mm) were obtained when the cut ends of the shoots were treated with 1.0 mg/L IBA and cultivated in Horticultural soil for 2 months. These findings suggest that ex vitro rooting is the more effective method for improving root formation in Vaccinium oldhamii than in vitro rooting.