S. TALARI, S.C. RUDROJU AND R.S. NANNA
Abstract
Our present investigation reports on the rapid and high frequency regeneration through direct in vitro organogenesis and plantlet development from hypocotyl explants of an endangered medicinally important forest tree Oroxylum indicum. The hypocotyl explants were inoculated on MS (Murashige and Skoogâs) medium fortified with different concentrations of BAP/Kn used also in combination with 0.5mg/L 2, 4 D. The multiple shoots were developed in all the concentrations of BAP/ Kn used and also in combination with 0.5 mg/L 2.4 D. The maximum number of shoots/explant was found at 2.0mg/L 2.4 D+5.0 mg/L BAP. The in vitro raised micro-shoots were subcultured on MS medium augmented with 1.0mg/L BAP+0.5 mg/L GA3 for further shoot proliferation and elongation. These microshoots were cultured on ½ strength MS medium supplemented with various concentrations of IAA/IBA/NAA for in vitro rooting. Profuse rhizogenesis was recorded at 1.0mg/L IBA. These in vitro rooted plantlets were acclimatized in culture room, later transferred to research field and maintained under shady conditions. These in vitro developed plantlets were identical to their mother plant with 85% of survival. The present protocol reports the direct organogenesis in O. indicum from hypocotyls explants followed by successful establishment of regenerated plants under green house conditions and can be used for conservation and rapid multiplication of the potential medicinal forest tree species. Abbreviations: BAP-Benzyl amino purine; GA3-Gibberellic acid, NAA-α-Naphthelene acetic acid, 2, 4 D- 2,4-Dichloro phenoxy acetic acid, MS-Murashige and Skoogâs, PGR-Plant growth regulators.