Abstract
Two efficient somatic embryogenesis systems were developed in Chinese fir, the most important conifer for industrial wood production in China. Three development stages (cleavage polyembryony, dominant embryo, and precotyledon) of immature embryos derived from 25 genotypes of open-pollinated mother trees were used as initial explants. Cleavage polyembryony-stage embryos with a 12.44% induction rate was the most embryogenic response stage. The highest frequency of embryogenic callus (13.86%) induction was obtained from DCR medium supplemented with 1.5 mg L−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.3 mg L−1 kinetin (KN). An average of 53.33 early somatic embryos were produced from approximately 0.2 g (fresh weight) embryogenic callus after 2 weeks of incubation on medium supplemented with 50 μmol L−1 abscisic acid (ABA) and 100 g L−1 polyethylene glycol (PEG) 6000. About 53% dominant embryos have an embryogenic response after a 6-week cultivation on medium supplemented with 1.0–2.0 mg L−1 benzyladenine (BA), 0.2 mg L−1 naphthylacetic acid (NAA) or 2,4-D, and 0.004 mg L−1 thidiazuron (TDZ). After three successive transfer cultures on medium supplemented with 1.5 mg L−1 BA, 0.2 mg L−1 NAA, and 0.004 mg L−1 TDZ, 4.49–16.51% of the embryos developed into somatic embryos.
Highlights
Since the 1960s, systematic genetic improvements have been carried out in Chinese fir
SE has been induced in Chinese fir with the initial cotyledon and hypocotyl explants and mature zygotic embryos by direct SE pathway, i.e., all of the somatic embryos were produced by direct SE without mediation of the embryogenic callus[17, 18]
Since the first report that morphologically and physiologically mature somatic embryos could produce vigorous plantlets from embryogenic callus induced from immature Picea abies embryos[8], the greatest success in inducing SE in coniferous species has occurred with immature zygotic embryos
Summary
Since the 1960s, systematic genetic improvements have been carried out in Chinese fir. SE has been induced in Chinese fir with the initial cotyledon and hypocotyl explants and mature zygotic embryos by direct SE pathway, i.e., all of the somatic embryos were produced by direct SE without mediation of the embryogenic callus[17, 18]. The embryogenic callus ensures mass propagation for trees of elite and high-value genotype[20], and the indirect SE pathway via embryogenic callus intermediation may be another method to enhance Chinese fir SE yield. Embryogenic callus can be generated from a variety of tissues in coniferous species, including immature and mature zygotic embryos[21] and vegetative shoot apices[22]. The main objective of this study was to develop a reliable method for inducing SE in tissues from mature Chinese fir trees with an elite genotype. The ability of plant growth regulators and genotypes to induce an embryogenic response and the effects of ABA and PEG on somatic embryos maturation were studied
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
