Clerodendrum phlomidis L. f. is an important medicinal plant of the Lamiaceae family, particularly its roots, which are used for various therapeutic purposes in a pulverized form. The objective of this study was to develop a standard protocol for axillary shoot proliferation and rooting of C. phlomidis for its propagation and conservation. Nodal explants were inoculated on Murashige and Skoog (MS) medium that was supplemented with one of six cytokinins: 6-benzyladenine, kinetin, thidiazuron, N6-(2-isopentenyl) adenine (2iP), trans-zeatin (Zea) and meta-topolin. Callus induction, which was prolific at all concentrations, formed at the base of nodal explants and hindered shoot multiplication and elongation. To avoid or reduce callus formation with the objective of increasing shoot formation, the same six cytokinins were combined with 4 μM 2,3,5-tri-iodobenzoic acid (TIBA) alone or in combination with 270 μM adenine sulphate (AdS). Nodal explants that were cultured on the medium supplemented with 9.12 μM Zea, 4 μM TIBA and 270 μM AdS produced significantly more and longer shoots than on medium without TIBA and AdS. Half-strength MS medium supplemented with 8.05 μM α-naphthaleneacetic acid was the best medium for root formation. Most (75%) in vitro rooted plantlets were successfully acclimatized under natural conditions.
