Estabelecimento in vitro de segmentos apicais e formação de plântulas de libidibia ferrea (UL.) L. P. Queiroz

Abstract

Libidibia ferrea known as jucá, belongs to the Fabaceae a native family of Brazil, it is distributed in the North and Northeast. It is a medicinal species with therapeutic and antimicrobial properties with compounds of pharmaceutical importance. However, it has cutaneous numbness with difficulties in seed production, which impairs its propagation. So, the objetive of this paper was to verify the efficacy of disinfestation methods for nodal segments, and the influence of indolbutyric acid for the ex vitro establishment of L. ferrea apical segments. The study was conducted in two experiments at the LASTED Forestry and Digital Technologies laboratory. For experiment I, nodal segments were obtained from matrix plants of Campus III, INPA. The explants were submitted to different sodium hypochlorite solutions (0.10, 0.50 and 1%); 70% alcohol, systemic fungicide (25, 50, 75 and 100%), as well as the combination of these disinfectant agents. The results indicate that 100% of explants presented microbial contamination and oxidation and no treatment was efficient for in vitro establishment of nodal segments. Experiment II was developed in the LASTED nursery. Plant material was obtained from juvenile L. ferrea seedlings grown at INPA. The design used was completely randomized in a 3 x 3 factorial scheme, with a stake type: apical; three substrates: organic soil, vermiculite and organic soil + vermiculite; and three indolbutyric acid concentrations 0, 1000 and 3000 (mg L-1). The cuttings were conducted on three types of substrates in plastic trays. After 90 days the following variables were evaluated: survival (%), rooting (%), number of shoots, cut length (cm), root length (cm) and number of leaves. The results were submitted to variance analysis and the means were compared by Tukey test at 5% probability. The results showed that the jucá cuttings showed easy survival, rooting and uniform growth in all tested treatments. The combination of apical cuttings with organic soil + vermiculite substrate at IBA concentration 1000 (mg L-1) promoted a higher cuttings development. Keywords: juca, explant decontamination, cutting.