positive effect of arabinogalactan on induction of somatic embryogenesis in Quercus bicolor followed by embryo maturation and plant regeneration

• Published in: Trees (Berlin, West) Vol. 27; no. 5; pp. 1285 - 1296
• Main Authors: Mallón, Rubén, Martínez, Teresa, Corredoira, Elena, Vieitez, Ana M
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.10.2013; Springer Berlin Heidelberg; Springer Nature B.V
• Subjects: Agriculture; arabinogalactans; benzyladenine; Biomedical and Life Sciences; casein hydrolysates; cold storage; Culture media; Embryonic growth stage; Embryos; explants; Forestry; genotype; Genotypes; germination; Growth regulators; leaves; Life Sciences; naphthaleneacetic acid; Original Paper; Plant Anatomy/Development; Plant growth; Plant Pathology; Plant Physiology; Plant Sciences; plantlets; Quercus bicolor; root growth; salts; shoots; somatic embryogenesis; sorbitol; trees; Vitamins; wood; Shoot apex explant; Somatic embryo germination; Adult vegetative trees; Proliferating shoot cultures; Swamp white oak; Cold storage; Leaf explant
• ISSN: 0931-1890; 1432-2285
• DOI: 10.1007/s00468-013-0877-x

This is the first report on the successful induction of somatic embryogenesis in swamp white oak from leaf and shoot apex explants excised from in vitro shoot cultures derived from 6- to 7-year-old trees. We demonstrated that arabinogalactan from larch wood (2–4 mg/L) promoted embryogenesis in the three genotypes evaluated by increasing the frequency of somatic embryogenesis, the embryogenic sites per explant, and by speeding the onset of embryo initiation. The explants were cultured sequentially on three culture media consisting of Murashige and Skoog (MS) salts and vitamins supplemented with 500 mg/L casein hydrolysate and different concentrations of α-naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BA). Somatic embryogenesis induction frequencies of up to 12.4, 4.5, and 0.7 % were obtained for the three genotypes. Clonal embryogenic lines were maintained by repetitive embryogenesis following culture on MS medium containing 0.44 μM BA with or without 0.27 μM NAA. Before germination, cotyledonary-stage embryos were cultured for 4 weeks in maturation medium (MS medium with half-strength macronutrients) containing 6 % sorbitol. Germination response was significantly improved by applying a 2-month cold storage as a post-maturation treatment. The mineral formulation and plant growth regulator content of the germination medium influenced the frequency of plantlet conversion with the best results achieved on Gresshoff and Doy medium with BA (0.25–0.44 μM). This procedure resulted in over 50–60 % of germinating embryos exhibiting continuous root growth and either epicotyl elongation or shoot development.