The maturity level of explant plays a key role in somatic embryogenesis of the palm tree Syagrus oleracea [Mart.] Becc

• Published in: Acta physiologiae plantarum 2022-08, Vol.44 (8), Article 87
• Main Authors: Silva-Cardoso, Inaê Mariê de Araújo, Meira, Filipe Sathler, Scherwinski-Pereira, Jonny Everson
• Format: Article
• Language: English
• Subjects: 2,4-D; Abnormalities; Activated carbon; Activated charcoal; Agriculture; Auxins; Biomedical and Life Sciences; Callus; Charcoal; Dichlorophenoxyacetic acid; Embryonic growth stage; Embryos; Germination; Growth regulators; Life Sciences; Optimization; Original Article; Picloram; Plant Anatomy/Development; Plant Biochemistry; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Somatic embryogenesis; Syagrus oleracea
• ISSN: 0137-5881; 1861-1664
• DOI: 10.1007/s11738-022-03420-8

This study aimed to develop a somatic embryogenesis protocol and consequent regeneration of Syagrus oleracea (Mart.) Becc. plants, an important palm tree that produces bitter palm hearts. The influence of auxins 4-amino-3,5,6-trichloropicolinic acid (Picloram) and 2,4-dichlorophenoxyacetic acid (2,4-D) at four different concentrations (0, 225, 450, and 675 μM) in MS medium with 2.5 g L −1 activated charcoal were evaluated, as well as the influence of different maturity levels of inflorescences, classified based on spathe length (stage I—6–17 cm; stage II—21.5–35 cm; and stage III—41.5 cm). For differentiation of somatic embryos, auxins concentrations utilized were gradually reduced. For germination, somatic embryo-like structures were inoculated in MS medium without growth regulator with 1.5 g L −1 activated charcoal. Picloram was more efficient than 2,4-D for callus induction and somatic embryo-like structures formation. More immature tissues (stage I) from inflorescences are not necessarily more responsive to callus formation than less immature tissues (stage II and III), although they are more embryogenic than these. The embryogenic somatic process was relatively slow, asynchronous, and marked by abnormalities, such as fusion of somatic embryos. It was hypothesized that germination was limited due to the occurrence of fusion and precocious germination, which highlights the need for future optimization of the maturation and germination phase. The anatomical analyses confirm the bipolar organization of somatic embryos and suggest a multicellular origin for the somatic embryos.