Cultura de tecidos e produção de β-ecdisona em Pfaffia glomerata e Pfaffia tuberosa (Amaranthaceae)

Abstract

Many biotechnological techniques have been formed by new tools to the study of medicinal plants and for the production of homogenous and productive biomass. This work aimed to examine aspects of morphogenesis and callogenesis in Pfaffia glomerata and Pfaffia tuberosa as well as to evaluate the production of β-ecdysone in micropropagated plants, clones and calli in vitro. Nodal segments of two accessions (BRA and JB-UFSM) of P. glomerata were cultivated on Murashige and Skoog (MS) medium. In relation to P. tuberosa the process of disinfection, multiplication and acclimatization of the plants was studied. Studies referring to the induction of callus, organogenesis and embryogenesis were conducted using medium supplemented with auxins and cytokinins. Roots and aerial parts of the micropropagated plants, clones regenerated by indirect organogenesis and calli in vitro were analysed in relation to production of β-ecdysone by high efficiency liquid chromatography. Micropropagation proved to be a viable method for the production of P. glomerata plants on a commercial scale. The BRA accessions presented higher multiplication rate and β-ecdysone content when compared to JB-UFSM. Nodal segments of P. tuberosa showed an absence of microorganisms and a high survival rate after being washed with various disinfecting solutions. Better results in relation to micropropagation in this species were registered in medium with 1μM of thidiazuron, followed by subcultivation of shoots in medium without thidiazuron, where the plants showed excellent development and good adaptation to ex vitro conditions. After cultivation in the field, the β-ecdysone content found in these plants was similar to that found in wild plants in vivo. It was found that, in both studied species, the aerial parts of the plants accumulated a greater β-ecdysone content when compared to roots. Calli from nodal segments of P. glomerata showed differences in consistency, morphogenic potential and β-ecdysone content, depending on plant growth regulators concentrations added to the nutritive medium. In general, the production of this metabolite in the calli appear to be associated with the friable consistency and regeneration of shoots. In P. tuberosa the β-ecdysone content varied among the friable calli depending on the concentration of auxin and appear to be dependent on the regeneration of shoots. The P. glomerata calli presented a low plant regeneration frequency; the plants (clones) regenerated from calli presented normal morphology, but differed in relation to β-ecdysone content. In P. tuberosa several clones were regenerated from friable calli in medium MS with auxin or auxin and cytokinin. On the other hand, root explants formed embryogenic calli in medium MS with auxin and cytokinin. These biotechnological strategies involving cultivation techniques in vitro together with the dosage of β-ecdysone are pioneer studies for the genus and could be useful for the propagation and genetic breeding of these species of Brazilian ginseng.