ABSTRACT
ABSTRACT This work describes the establishment of procedures to induce in vitro callogenesis from Poincianella pyramidalis (Tul.) L. P. Queiroz, Fabaceae, explants. Nodal, internodal and leaf segments were isolated from in vitro germinated seedlings and cultured in MS medium with 0, 2.5, 5 and 10 mg l-1 of 2,4-dichlorophenoxyacetic acid. After 30 days, the explants with induced callus showed a quadratic response for the segments nodal, internodal and leaf, with increasing the callus formation in 2,4-dichlorophenoxyacetic acid concentrations of 6.28, 6.49 and 4.91 mg l-1, respectively. In 30 days there was a linear oxidation rise with the increase to the 2,4-dichlorophenoxyacetic acid. After 60 days, oxidation values were minimum, at 2,4-dichlorophenoxyacetic acid concentrations of 5.13 mg l-1 (internodal) and 3.98 mg l-1 (leaf). The highest callus production was observed after 30 days in the presence of 6.09 mg l-1, 5.82 mg l-1 and 4.91 mg l-1 of 2,4-dichlorophenoxyacetic acid in nodal, internodal and leaf segments, respectively. After 60 days these segments showed peaks of production at 7.0 mg l-1 (nodal), 6.15 mg l-1 (internodal) and 5.08 mg l-1 (leaf) of 2,4-dichlorophenoxyacetic acid. For callus induction the intake of 2,4-dichlorophenoxyacetic acid was essential. The greater intensity in callus formation was observed in 4.91 mg l-1 in leaf segments after 30 days.