In vitro regeneration of the tropical multipurpose leguminous tree Sesbania grandiflora from cotyledon explants.
Cotyledon explants derived from germinated seeds incubated in the dark for 24 or 36 h, resulted in the highest percentage (96%) of explants producing more than 30 buds each when cultured on MS medium supplemented with 1 mg NAA and 1 mg BA/litre for 3 weeks. Bud development occurred through a direct organogenesis pathway, from the proximal and adaxial cut surface of the explants as determined by histological evaluation. Additional regeneration sites were obtained after wounding the epidermal surface of the explants, suggesting a large distribution of regenerative cells all along the explants. The highest bud elongation was obtained when buds were isolated from cotyledon explants and subcultured in liquid MS medium supplemented with 0.5 mg benzyladenine + 0.1 mg NAA + 0.1 mg gibberellic acid/litre for one week. Rooting of 86% shoots was obtained on MS medium supplemented with 1 mg NAA. After 3 weeks plantlets were transferred to soil in a greenhouse and after 4 months the survival rate was 92%.