An efficient micropropagation system for Tylophora indica:: an endangered, medicinally important plant

An efficient protocol is described for the rapid in vitro multiplication of an endangered medicinal plant, Tylophora indica (Burm. f.) Merrill, via enhanced axillary bud proliferation from nodal explants collected from young shoots of a two-year-old plant. The physiological effects of growth regulators [6-benzyladenine (BA), kinetin (Kin) thidiazuron (TDZ), indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) or a-naphthalene acetic acid (NAA)], ascorbic acid (AA), different strengths of Murashige and Skoog ( MS) medium and various pH levels on in vitro morphogenesis were investigated. The highest number (8.6 +/- 0.71) of shoots and the maximum average shoot length (5.2 +/- 0.31 cm) were recorded on MS medium supplemented with 2.5 mu M BA, 0.5 mu M NAA and 100 mg/l AA at pH 5.8. Rooting was best achieved on half-strength MS medium augmented with 0.5 mu M IBA. The plantlets regenerated in vitro with well-developed shoot and roots were successfully established in pots containing garden soil and grown in a greenhouse with a 90% survival rate. The regenerated plants did not show any immediate detectable phenotypic variation. The described method can be successfully employed for large-scale multiplication and long-term in vitro conservation of T. indica.