In vitro flowering of shoots regenerated from cultured nodal explants of Spilanthes acmella Murr. - an ornamental cum medicinal herb

An efficient protocol for in vitro flowering of Spilanthes acmella Murr., a medicinally valuable plant, has been developed. Multiple shoot formation of up to 4 shoots was obtained on Murashige and Skoog (MS) medium supplemented with BAP (1.0 mg/l). Regenerated shoots were subcultured cultured on MS medium containing various concentrations of BAP alone or in combination with IAA. Presence of BAP in the culture medium was observed to be absolutely essential for induction of flower. Maximum percentage (50 %) of flower induction occurred when regenerated shoots were cultured on MS medium supplemented with BAP (2.0 mg/l) + IAA (0.5 mg/l) under photoperiod of 16/8 h (light/dark cycle).The 3-week intervals for three consecutive subcultures on this medium were efficient for flower induction. The regenerated shoots rooted best on 1/2 MS medium containing IBA (1.0 mg/l). Rooted plantlets were hardened and established in pots with 70% survival rate.