STUDIES ON IN VITRO PROPAGATION OF BAUHINIA VARIEGATE

Bauhinia variegate L. (orchid tree) is very difficult to propagate by cuttings and commercially it is propagated by seed. So, in the present work the micropropagation of the species was studied in order to develop an efficient method for clonal propagation. Shoot tip explants, as well, as single node explants from the apical four nodes of young shoots (25 or 80 cm long), that developed after pruning one-year old seedlings were used. They were cultured in solid (8 g/L agar) MS medium, with 30 g/L sucrose, supplemented with NAA/BA at 0/0, 0/0.5, 0/1, 0.5/0.5, or 0.5/1 mg/L. Shoot tip or single node explants from 3-leaf (two-week old) seedlings were also used. Media supplemented with only BA favoured the development of shoots on explants. Explants of the 3rd, 4th and 5th node gave more (70-100% response) and longer (1.5-2.0 cm) shoots, with 3-5 leaves each, compared to shoot tip and 2nd node explants. Explants excised from 25 cm long shoots or from young seedlings (3-leaf) yielded a higher shoot number compared to those from 80 cm long shoots. Microshoots of various lengths were placed for rooting on MS or half strength MS with 30 g/L sucrose, supplemented with 0.2, 0.5, 2.0, 5.0 or 10 mg/L IBA. Rooting occurred only in half strength MS media. Maximum rooting noted on microshoots that were 2-4 cm long cultured on a medium supplemented with 2 mg/L IBA. Leaf lamina explants produced callus when cultured on MS with various concentration of 2,4D and BA. Subculture of this callus on media with various NAA/BA or 2,4-D/BA concentrations failed to give organogenesis.