SYNERGISTIC EFFECT OF DFMO AND 2,4-D ON REGENERATION OF TABERNAEMONTANA-PERSICARIAEFOLIA JACQ IN-VITRO

Callus cultures of Tabernaemontana persicariaefolia, (Apocynaceae), an endangered species endemic to the Mascarene Islands, were established from leaf explants on MS medium containing either 5 mg.l(-1) 2,4-D an d 0.5 mg.l(-1) BA or 5 mg.l(-1) 2,4-D, 0.5 mg.l(-1) BA and 200 mg.l(-1 ) DFMO. Histological studies showed regenerating nodules resembling gl obular embryos in calli after 4 weeks on the DFMO medium. Green shoot formation was achieved by sequential subculture of the induced calli o n media with gradually decreasing 2,4-D concentrations (5-->1-->0 mg.l (-1)). Regeneration was greatly stimulated in the presence of DFMO. Th e first emergence of shoots occured 3 weeks earlier than in untreated callus cultures.