Abstract :
Keywords: Arecaceae; Açaí palm; Amazonian biome; Morphogenesis; Palm heart; Somatic embryos Abstract An efficient, reproducible, and unprecedented protocol of somatic embryogenesis (SE) was developed from leaf tissues of adult plants of Euterpe precatoria Mart., palm tree of the Amazon biome of great economic potential. For callus induction, immature leaf segments from the proximal (closest to the meristem), median and distal regions of the palm heart were cultivated in MS and Y3 basal media containing Picloram or 2,4-D auxins in different concentrations. The effect of combining cytokinin 2iP (45 µM) with Picloram or 2,4-D (450 µM) was also evaluated, in addition to the palm heart region and basal media. The multiplication of embryogenic structures was carried out in basal media with a reduced concentration of growth regulators. For somatic embryos maturation, the following were tested: MS medium with reduced concentration of salts (half-strength MS) basal MS + 5 µM abscisic acid (ABA) basal MS + 25 g L.sup.-1 polyethylene glycol (PEG) 6000 basal MS + 60 g L.sup.-1 sucrose and basal MS + 2.5 µM ABA + 12.5 g L.sup.-1 PEG 6000. Mature somatic embryos were then inoculated at half-strength MS for germination. Anatomical and histochemical analyses of materials from the different phases of the process were performed. Higher efficiency of the MS medium with 450 µM Picloram and 45 µM 2iP was observed in the induction of callogenesis, with the formation of somatic embryos still in this phase. The apical and median regions were the most responsive for callus formation. The rate of proliferation of embryogenic structures was high and remained up to 180 d in the multiplication medium. The maturation treatments are efficient. Specifically, the treatment basal MS + 2.5 µM ABA + 12.5 g L.sup.-1 PEG 6000 provided greater individualization of somatic embryos. After 30 d in the germination medium, complete germination was verified. Anatomical analyses revealed evidence of unicellular origin. This study provides a first protocol capable of promoting the vegetative propagation from leaf tissues of Euterpe precatoria by SE. Author Affiliation: (1) Department of Forest Engineering, University of Brasília, Brasília, DF, Brazil (2) CNPq/Embrapa Postoctoral Fellowship Program, Embrapa Genetic Resources and Biotechnology, Brasília, DF, Brazil (3) Department of Botany, University of Brasília, Brasília, DF, Brazil (4) Center for Biological and Natural Sciences, Federal University of Acre, Rio Branco, AC, Brazil (5) Embrapa Genetic Resources and Biotechnology, Parque Estação Biológica, PqEB, 70770-917, Brasília, DF, Brazil (e) jonny.pereira@embrapa.br Article History: Registration Date: 10/03/2022 Received Date: 05/01/2022 Accepted Date: 09/30/2022 Online Date: 10/28/2022 Byline: