ABSTRACT
Objective:To determine the effects of different cytokinins at various concentrations on in vitro shoot multiplication of an important medicinal plant. Methods: Nodal explants (1.5-2.0 cm) of Sophora tonkinensis were used. Multiple shoots were induced from nodal explants cultured on the Murashige and Skoog (MS) medium supplemented with 0.0, 0.5, 1.0, 2.0, 4.0, 8.0, or 16.0 μmol 2-isopentyladenine (2iP), N6 benzyladenine, kinetin or thiadiazuron. Results: Among the four investigated cytokinins, 2iP showed the best response for shoot multiplication. Maximum shoot induction (75%) was achieved on the MS medium supplemented with 2.0 μmol 2iP, with a mean number of 5.0 shoots per explant. In comparison to other cytokinins tried, 2iP showed the highest shoot elongation with a mean shoot length of 4.8 cm. Root initiation was observed within 15 d within the transfer of shoots onto the MS basal medium, and the rooting percentage was 100%with a mean number of 5.4 roots per shoot and root length of 6.2 cm over a period of 4 weeks. The healthy plants, hardened and transferred to a greenhouse for proper acclimatization, exhibited 100%survival. Conclusions:It can be summarized that 2iP is the optimal plant growth regulator for Sophora multiplication.