Medicinally important and endangered plant species R. serpentina belongs to family Apocynaceae, is a woody perennial shrub which has been used for treatment of different mental disorders. In this study, In-vitro propagation (Callus and shoot formation) of  R. serpentina was studied by using different explants (Shoot tips, Nodal parts, internode parts and leaves) under the influence of different concentrations of BAP in combination with different concentrations 2-4 D and NAA. In both combinations of PGRs (BAP+2,4-D and BAP+NAA), highest percent shoot induction and highest percent callus formation was achieved from nodal part and leave explant respectively. PGRs concentration (1.0mg/l BAP + 0.5 mg/L 2-4 D) result higher number of shoot  and highest callus formation (70%) from nodal and leaf explant respectively while no callus was observed all explant part used except leave explant. Direct shoot formation was not observed in internode explant in all concentrations and combinations of PGRs used. PGRs concentrations (1.0mg/l BAP + 0.5 mg/L 2-4 D) and (0.8mg/l BAP + 0.2 mg/L NAA) gave explant gave highest percent callus formation from leave explant. The combination of BAP with 2-4 D gave less number of multiple shoots. The combined effect of BAP, 2-4 D and NAA at different concentrations was thus found significant and gave moderate formation of callus and multiple shoots from the explants. The combined effect of BAP, 2-4 D and NAA at different concentrations was thus found significant and gave moderate formation of callus and multiple shoots from the explants. The optimized protocol developed in our work could be useful in micro-propagation, large-scale multiplication and conservation of this endangered plant R.serpentina.

Index Terms- Tissue culture techniques, Medicinal plant, BAP, multiple shoot formation, callogenesis