Neo-formation of flower buds and other morphogenetic responses in tissue cultures of Melia azedarach

Melia azedarach has great interest because of its insecticidal properties. Recently, the occurrence of precocious flowering in tissue cultures of this species was reported. This paper describes some in vitro morphogenetic responses using hypocotyl segments as explants and MS basal medium. Amongst the results we report are: (a) in basal medium, 5% of the explants neo-formed floral buds and flowers, and 80% formed vegetative shoots; (b) flower neo-formation could not be controlled or increased by addition of benzyladenine, or lowering the nitrogen level; (c) benzyladenine increased the regeneration of vegetative shoots; (d) compact green calluses were eventually formed in basal medium, and vigorous friable calluses can be easily induced with 0.5 mM 2,4-D; (e) green calluses could be subcultured and regenerated into plants, and, from friable calluses, cell suspensions were started; (f) histological studies showed that neo-formations originate in the wound tissue or from the inner tissue of the hypocotyl.