In vitro plantlet regeneration in Panax sikkimensis.

A three-step procedure for complete plantlet regeneration via somatic embryogenesis has been developed in Panax sikkimensis. Somatic embryos (SE) were induced in root callus upon lowering the level of 2,4-D from 1.0 mg/l to 0.25 mg/l in the callusing medium. Maturation of SE occurred on a half-strength MS medium with 0.5 mg/l each of BAP and GA3. An exposure for 15 days of cotyledonary and heart-shaped SE to 1.0 mg/l IBA in liquid shake 1/2 MS medium significantly improved the rate of embryo-to-plantlet conversion and plantlet quality. The procedure has now allowed the retention of high regeneration potential of the root callus for over three years.