Direct shoot organogenesis from leaf explants of Embelia ribes Burm. f.:: a vulnerable medicinal plant

An efficient system was developed for direct plant regeneration from in vitro-derived leaf explants of Embelia ribes Burm. f., a vulnerable medicinal woody climber of the Western Ghats of India. The in vitro procedure involved three steps that included induction of shoot initials from leaf tissue, regeneration and elongation of shoots from the shoot initials, and rooting of shoots. The induction of shoot initials was achieved on Murashige and Skoog (MS) solid medium supplemented with different concentrations of thidiazuron (TDZ). The best medium for shoot induction was MS with 0.272 mu M TDZ. Numerous shoot primordia developed within 2-3 weeks on the leaf margin as well as on the midrib region, without any callus phase. In the second step, the shoot clumps separated from the leaf explant on transfer to MS basal medium, resulting in the differentiation of 90% of the shoot initials into well-developed shoots. The 2- to 3-cm-long shoots rooted on half-strength MS basal medium supplemented with 4.90 mu M indole-3-butyric acid (IBA) and 3% (w/v) sucrose in the third stage. The rooted plants could be established in soil with 70% success. This protocol could be utilized for in vitro propagation and conservation of this important threatened medicinal plant.