Oxidação fenólica, tipo de explante e meios de cultura noestabelecimento in vitro de canafístula (Peltophorum dubium (Spreng.) Taub.)

Peltophorum dubium (Spreng.) Taub. is a heliopylous, a native forest species with wide geograficdispersion, occuping a pioneer role in open areas, hencoops and degradated woods. Showing a fast growth, itadapts easily and it is highly recommended for homogeneous reforest. The timber is used in industrialfurniture, 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. Theworks objectives are: to evaluate the effect of the light on phenolic oxydation and to determinate the mostappropriate nutritive medium and type of explant for in vitro establishment of Peltophorum dubium. Twoexperiments were accomplished. In the first one, apical segments were cultivated in MS base medium at25±3°C, during seven days in the dark; after that, they remained in the presence of light (photoperiod of16h) for 14 days. In the other treatment, the explants stayed under light during the whole experiment (21days). Completely random design with five replicates and four experimental units (EU) were used. Phenolicoxydation did not occur in any of the analyzed treatments. In the second assay, apical segments and nodalsegments were cultivated in MS base medium and WPM medium. The explants stayed in the growth roomduring 16h of photoperiod and luminous intensity of 20 µmol.m2.s-1, supplied with cool white fluorescentlamps, at 25±3°C. The EU was composed by one 150mL flask with 30mL of nutritive medium and oneexplant. Completely random design with factorial outline 2 x 2 (nutritive medium and type of explant) andfive replicates by treatment, each replicate with four EU, were used. After 49 days, the following elementswere evaluated: survival, establishment, root presence, calli presence, numbers of nodes, number of leavesand shoot height (mm). The data of survival, establishment, root presence and calli presence were analyzedfor qui-quadrado test. The other variables were submitted to variance analysis. In this experiment, MS basemedium is more efficient than WPM medium in the in vitro establishment of Peltophorum dubium. There areno statistical differences among apical segment and nodal segment.