In vitro culture of zygotic embryos of Butia eriospatha

Resumo

The economic use of Butia eriospatha is justified by its potential but is limited by its slow germination. The in vitro culture of zygotic embryos can solve this problem as well as contribute to the conservation and to insert this species in the productive context. The objectives of this study were to evaluate the procedures for surface disinfestation, the effect of gibberellic acid (GA3) on in vitro germination, and the effect of 3 culture media on the increase in fresh mass of zygotic embryos of Butia eriospatha. In the first assay, disinfestation was tested by immersing only the seeds, by immersing the seeds followed by isolation of the embryos, and by immersing only the embryos in sodium hypochlorite (NaOCl). After 30 days of in vitro culture, microorganism contamination was evaluated. In the second assay, in vitro germination was tested using different concentrations (0, 2, 4, 6, and 8 mg·L-1) of GA3. In the third assay, 3 culture media (Murashige and Skoog [MS], woody plant medium [WPM], and Y3) were evaluated. Soaking embryos in NaOCl, with or without seed immersion, produced satisfactory control of microorganisms, unlike the disinfestations tests conducted only on the seed, which were not efficient. In vitro germination of embryos increased with the GA3 concentration. Embryos cultured in Y3 and MS culture media showed a higher increase in fresh mass than those cultured in WPM. To control microorganisms, disinfestation consisted of immersing the seed in 2% NaOCl for 15 min followed by immersing the embryo directly in 1% NaOCl for 10 min. A GA3 concentration of 8 mg·L-1 was required to optimize the germination. After 4 weeks of the in vitro culture, 80% of the embryos germinated. Thus, the use of MS or Y3 culture media is recommended to promote the in vitro growth of Butia eriospatha zygotic embryos.