Explant age and genotype drive the somatic embryogenesis from leaf explants of Acrocomia aculeata (Jacq.) Lodd. ex Mart. (Arecaceae), an alternative palm crop for oil production

Key message

A complete system of regeneration, via somatic embryogenesis, from the in vitro culture of leaflets explants of young A. aculeata donor-plants has been reported.

Abstract

In the present study, a complete regeneration protocol of Acrocomia aculeata (Jacq.) Lodd. ex Mart., via somatic embryogenesis is reported, and the influence of the genotype and its age on the induction of the embryogenic process determined. Leaflets explants of 4 genotypes, aged 2 and 5 years, were inoculated in the induction medium consisting of salts and vitamins Y3 supplemented with different concentrations of picloram (9.0, 18.0 and 36.0 µM). In the control, no plant growth regulators were added. Picloram concentrations of 18.0 and 36.0 µM induced greater formation of embryogenic calluses in all genotypes studied. However, 2-year-old genotypes had higher percentages of embryogenic calluses. In addition, at the highest concentration of picloram (36.0 µM), 5-year-old genotypes had the highest oxidation rates. Differentiation of somatic embryos was observed in medium supplemented with 9.0 and 18.0 µM picloram and 1 mM putrescine. However, at a concentration of 9.0 µM, the somatic embryos showed a high degree of fusion. Embryogenic lines were only obtained in medium supplemented with 18.0 µM picloram and 1 mM putrescine. Histochemical analysis showed the presence of pectins in embryogenic cultures and starch grains in peripheral regions of embryogenic calluses, which were not directly involved in regeneration. Somatic embryos were converted into plantlets after 90 days in germination medium containing 0.54 µM NAA, 1 mM putrescine and 3.0 g L⁻¹ activated charcoal, highlighting the potential of the propagation system proposed here for clonal propagation of A. aculeata.