ABSTRACT
Peltophorum dubium (Spreng.) Taub. is a heliopylous, a native forest species with wide geografic dispersion, occuping a pioneer role in open areas, hencoops and degradated woods. Showing a fast growth, it adapts easily and it is highly recommended for homogeneous reforest. The timber is used in industrial furniture, civilian, naval and military constructions. The micropropagation is a technique used succesfully, allowing a fast increase of the number of plants genetically identical considering the superior types. The work’s objectives are: to evaluate the effect of the light on phenolic oxydation and to determinate the most appropriate nutritive medium and type of explant for in vitro establishment of Peltophorum dubium. Two experiments were accomplished. In the first one, apical segments were cultivated in MS base medium at 25±3°C, during seven days in the dark; after that, they remained in the presence of light (photoperiod of 16h) for 14 days. In the other treatment, the explants stayed under light during the whole experiment (21 days). Completely random design with five replicates and four experimental units (EU) were used. Phenolic oxydation did not occur in any of the analyzed treatments. In the second assay, apical segments and nodal segments were cultivated in MS base medium and WPM medium. The explants stayed in the growth room during 16h of photoperiod and luminous intensity of 20 µmol.m2.s-1, supplied with cool white fluorescent lamps, at 25±3°C. The EU was composed by one 150mL flask with 30mL of nutritive medium and one explant. Completely random design with factorial outline 2 x 2 (nutritive medium and type of explant) and five replicates by treatment, each replicate with four EU, were used. After 49 days, the following elements were evaluated: survival, establishment, root presence, calli presence, numbers of nodes, number of leaves and shoot height (mm). The data of survival, establishment, root presence and calli presence were analyzed for qui-quadrado test. The other variables were submitted to variance analysis. In this experiment, MS base medium is more efficient than WPM medium in the in vitro establishment of Peltophorum dubium. There are no statistical differences among apical segment and nodal segment.
Keywords:
MS medium; WPM medium; apical segment; nodal segment