Resgate de material adulto e propagação in vitro de Schizolobium parahyba var. amazonicum (Huber ex Ducke) Barneby

Abstract

This study aims to evaluate whether it is possible to establish protocols for the introduction, multiplication and in vitro rooting of shoots of Schizolobium parahyba var. amazonicum (Huber ex Ducke) Barneby derived from the rescue of vegetative material from adult individuals of the species by the semi-annulation technique. For the application of the semi-girdling technique, forty-eight progenies with approximately 4.5 years of age were used, established in a plantation in the experimental area of Embrapa Agrossilvopastoril that were submitted to the technique of basal and superior semi-girdling of the stem, with application of the growth regulator 6- benzylaminopurine (BAP), at doses of 0, 500, 1000 and 2000 mg L-1 in the ring region. The mean number of shoots (NB) and the mean length of shoots (CB) were evaluated every 7 days until 120 days. For in vitro introduction, the semi-annealing buds were introduced in MS medium, plus activated charcoal and PVP as antioxidants. The shoots were submitted to different times of disinfestation (0, 5, 10 or 15 minutes) in a 2.5% (v/v) sodium hypochlorite solution with the addition of Tween 20 detergent, followed by rinsing the material in 6 cycles with distilled and autoclaved water. The evaluations were carried out during a period of 30 days, in which, weekly, the incidence of fungal and bacterial contamination (CF), oxidation (OX) and explant survival rate (TS) were evaluated. In order to establish an in vitro multiplication protocol, cotyledonary and apical segments from in vitro germinated seeds were submitted to different concentrations (0.0; 0.5; 1.0; 2.0 mg L -1) of cytokinins (BAP) and kinetin (KIN), in WPM culture medium, at 25 days the number of buds per explant (NBE), length of the largest bud (CMB) and the percentage of bud (CP) were calculated. For in vitro rooting, segments from the multiplication stage were used, which were submitted to different concentrations (0; 0.5; 1.5; 3.0 mg L -1) of indolebutyric acid (IBA) and naphthaleneacetic acid (NAA), where at 60 days the percentage of rooting (PE), total number of roots (NTR) and average root length (CMR) were evaluated. For the basal semi-girdling technique, there was no significant interaction between the evaluated progenies and the different doses of BAP tested. The technique of superior semi-girdling of the stem did not guarantee the emission of shoots for any progeny at any of the doses tested. The in vitro establishment of shoots from vegetative rescue showed high rates of contamination and no material was used. In the in vitro multiplication, the variable NBE and PB showed significant interaction for the segment and cytokinin used. The highest average of budburst per explant (1.45) was obtained with the association of the cotyledonary segment and cytokinin BAP, the same happened for the variable PB, the highest average 85,45%. The CMB variable showed only the effect of isolated factors. It was not possible to obtain rooting of S. parahyba var. amazonicum.