A callus induction and plant regeneration protocol was developed from leaf explants of the endemic Spilanthes acmella. Explants were cultured on Murashige and Skoog medium (MS) supplemented with different plant growth regulators (PGRs) [α-naphthaleneacetic acid (NAA), BAP and IBA, 2 4-dichlorophenoxyacetic acid (2, 4-D), Zeatin]. The combinations and concentrations of PGRs were shown significant variations for the frequency of callus formation, appearance of callus and the potential of callus differentiation. 2, 4-D (5mg/lit) alone while BAP 0.5mg/l with NAA 5.0mg/l have been found highly effective in callusing with quite good in texture and friable in nature 90% to 80% respectively along with single shoots. After the callus formation the formed callus were cultured on different combinations of BAP and NAA and BAP and Zeatin for multiple shoots and shoot elongation. MS medium containing 2.0 mg/l BAP and 1mg/l Zeatin was found to be the best medium for maximum in vitro response i.e., 93% shooting and multiple shoots (7.5)with maximum 8cm in length. Best rooting was achieved on half strength MS medium fortified with 1mg/l NAA respectively.
