Desinfestação e estabelecimento in vitro de segmentos caulinares de camu-camuzeiro

Abstract

The camu-camu tree (Myrciaria dubia (H.B.K.) McVaugh) is a fruit-bearing species belonging to the family Myrtaceae of spontaneous occurrence on the banks of rivers and lakes of Amazonia. It presents economic potential, since its fruits are thought the greatest natural source of vitamin C, bordering 6,112g of ascorbic acid per 100 g of pulp, arising commercial interest on the part of the farmers and consumers. In spite of the economic importance, little is known about the aspects of the in vitro multiplication of this species, which could raise significantly its yield. In this sense, it was aimed through this work to test different concentrations of products for disinfestation and establishment of an aseptic culture by utilizing explants of stem segments of camu-camu coming from mother plants kept in ex vitro environment. The work was divided into four experiments: 1) evaluation of the effect of sodium hypochlorite upon the asepsis of the explants of stem segments of camu-camu in vitro; 2) to evaluate different concentrations of mercury chlorite in the in vitro disinfestation of camu-camu stem segments; 3) to determine the best concentration and immersion time of chlorine dioxide in the in vitro disinfestations of camum-camu stem segments; 4) Use of antibiotics for the control of bacterial contamination in in vitro cultures of camu-camu stem segments. After 30 days‟ time, the percent of contamination and the percentage of established explants were evaluated. The use of sodium hypochlorite at 1.5%of active chlorine for 12 minutes provided highest percentages of decontamination (98%), which resulted into the obtaining of good establishment indices (87.9%). Mercury chlorite proved toxic to the explants even at the lowest concentrations. Through the use of chlorine dioxide at the concentration of 50% under exposition in the 30 minutes‟ time, 60% of the disinfected explants and 50% of the established ones were obtained. As to the antibiotics, decreased contamination indices and increased establishment indices (0% and 50%, respectively) were reached when ampicillin at the concentration of 100 mg/ L was utilized. Therefore, for in vitro disinfection of camu-camu tree via stem segments, one should utilize 1.5% sodium hypochlorite for 12 minutes, with addition in the culture medium of 100 mg/ L of antibiotic ampicillin.