IN VITRO OF Melanoxylon brauna SCHOTT. MORPHOGENESIS: RESPONSIVENESS OF EXPLANTS TO PERMANENT AND TEMPORARY IMMERSION GROWTH REGULATORS

Abstract

Melanoxylon brauna is propagated by seeds, however, low yield, pest attack and short viability are problems in seedling production. Plant tissue culture is an alternative for large-scale seedling production, but studies with this species are scarce. The objective of this study was to study in vitro morphogenesis of M. brauna after induction of growth regulators. Three experiments were performed: I. In vitro bud proliferation of juvenile M. brauna explants at different BAP concentrations. The number and length of shoots (mm) was analyzed; bud explants^-1 (%); calogenesis (%) and direct and indirect organogenesis budding^-1 (%). II. In vitro rhizogenesis of M. brauna shoots with different types and auxin concentrations; III. In vitro rhizogenesis of M. brauna under temporary immersion of shoots at different IBA concentrations. Calogenesis (%) was analyzed; rhizogenesis (%); number, length (mm) and root dry mass (mg). The nodal segment with two axillary buds was the most responsive explant in the formation of shoots with BAP (1 mg L^-1). The auxin concentrations of IBA, ANA and 2,4-D were not favorable to rhizogenesis in MS culture medium. However, IBA concentrations of 2544.81 and 2607.52 mg L^-1 promoted superior results in rhizogenesis and shoot emission, respectively, when submitted to explant bases in temporary immersion in this auxin and planted in vermiculite substrate.