Cultivo in vitro de Tocoyena brasiliensis MART. (RUBIACEAE)

Abstract

Tocoyena brasiliensis Mart. is popularly known as jenipapo bravo or genipapinho. It is a native species, endemic to Brazil, widely distributed, being found in the phytogeographical domains of the Amazon, Caatinga, Cerrado and Atlantic Forest. Because of the rusticity and adaptation to poor soils, the species can be used to recover degraded areas, as well as, due to its prolonged flowering, green canopy throughout the year and small size, has great potential for ornamental use in urbanization. To date, no studies on the propagation of the species have been found in the literature. In this sense, considering the characteristics of the species and its potential in the recovery of degraded environments, this work was developed with the objective of evaluating the in vitro propagation of the species. The vegetative material was obtained from seedlings obtained from seeds previously germinated in vitro. In order to reach the proposed objective, the in vitro growth of explants grown in medium formulated with microalgae of the species Chlorella sorokiniana (Chlorophyceae) as an alternative medium and / or supplement to the commercial medium WPM (Wood Plant Medium) in the presence and absence of indole-3-acetic acid (3-IAA) gibberellic acid (GA3), 2-isopentenyl adenine (2iP), and zeatin. Subsequently, the tolerance of the species to different heavy metals, zinc acetate (ZnC4H6O4), cadmium chloride (CdCl2) and lead acetate (Pb (C2H3O2)2) were evaluated in different concentrations, which were added to the WPM medium. Although the results of in vitro multiplication show that the cultivation of T. brasiliensis in medium formulated with microalgae reduced the number of shoots, the same medium can be used in the rooting stage, since the explants did not develop calluses. In order to obtain more shoots during the in vitro multiplication of the species, the WPM medium free of growth regulators is more effective. As for the species' tolerance to metals, concentrations above 200 mg L-1 of zinc cause toxicity and may lead to the death of the explants. However, it is possible to indicate Tocoyena brasiliensis as lead and cadmium tolerant, since the survival rate of explants in medium supplemented with these metals was higher than 90% at the highest concentrations.