In vitro propagation of Brazilian ginseng [Pfaffia glomerata (Spreng.) Pedersen] as affected by carbon sources

Abstract

This study aimed to establish a protocol for in vitro propagation of two accessions (Ac) of Pfaffia glomerata (Ac 4 and Ac 13) and to evaluate the effect of different carbon sources on the production of 20-hydroxyecdysone (20E) in leaves and roots. For the assessment of axillary shoot proliferation in vitro, nodal segments were inoculated onto Murashige and Skoog (MS) medium supplemented with 2.22 μM 6-benzyladenine and 2.68 μM α-naphthaleneacetic acid and carbon sources (glucose or sucrose) at varying concentrations (0.1, 0.2, or 0.3 M). To assess the in vitro production of 20E, nodal segments were inoculated into Magenta® containers containing MS medium with different carbon sources (glucose, sucrose, or glucose + sucrose at 0.1 or 0.2 M) and placed in plastic bags with bacterial filters. Both experiments were composed of five repetitions for each treatment and analyzed after 30 d of culture. Multiple shoot formations were genotype-dependent when segments were cultivated on a medium supplemented with glucose or sucrose at 0.1 M, yielding 35 and 43 shoots per explant for Ac 4 and 4.4 and 2.8 shoots per explant for Ac 13, respectively. For the 20E content, significant effects were also observed among accessions and carbon sources. Ac 13 had the highest average 20E levels for both roots and leaves. Under the experimental conditions, Ac 4 had more favorable characteristics for large-scale multiplication than Ac 13, and glucose at 0.2 M was the best carbon source for the cultivation of Pfaffia, both for producing multiple shoots and for in vitro 20E production. This is the first report using a combination of auxin and cytokinin to enable effective Pfaffia in vitro axillary shoot proliferation from nodal explants.