Micropropagation of Spilanthes acmella L., a bio-insecticide plant, through proliferation of multiple shoots.

S. acmella [Blainvillea acmella] was successfully micropropagated using axillary buds as explants. The aseptic axillary buds formed multiple shoots within 5 weeks when cultured on MS medium supplemented with 2.0, 4.0, 6.0 and 8.0 mg benzyladenine (BA)/l. The addition of IBA as low as 2 mg/l into the MS medium containing BA had no significant effect on the multiple shoot formation. MS medium supplemented with 0.5 mg BA/l was sufficient for the proliferation of rooted multiple shoots. First subculturing of the in vitro individual shoots in the same proliferation medium could double the formation of multiple shoots.