title: Effect of light conditions on anatomical and biochemical aspects of somatic and zygotic embryos of hybrid larch (Larix × marschlinsii).
abstract: OBJECTIVE
  In conifers, mature somatic embryos and zygotic embryos appear to resemble one another physiologically and morphologically. However, phenotypes of cloned conifer embryos can be strongly influenced by a number of in vitro factors and in some instances clonal variation can exceed that found in nature. This study examines whether zygotic embryos that develop within light-opaque cones differ from somatic embryos developing in dark/light conditions in vitro. Embryogenesis in larch is well understood both in situ and in vitro and thus provides a suitable system for addressing this question.
  
  
  METHODS
  Features of somatic and zygotic embryos of hybrid larch, Larix × marschlinsii, were quantified, including cotyledon numbers, protein concentration and phenol chemistry. Somatic embryos were placed either in light or darkness for the entire maturation period. Embryos at different developmental stages were embedded and sectioned for histological analysis.
  
  
  RESULTS
  Light, and to a lesser degree abscisic acid (ABA), influenced accumulation of protein and phenolic compounds in somatic and zygotic embryos. Dark-grown mature somatic embryos had more protein (91·77 ± 11·26 µg protein mg(-1) f.wt) than either dark-grown zygotic embryos (62·40 ± 5·58) or light-grown somatic embryos (58·15 ± 10·02). Zygotic embryos never accumulated phenolic compounds at any stage, whereas somatic embryos stored phenolic compounds in the embryonal root caps and suspensors. Light induced the production of quercetrin (261·13 ± 9·2 µg g(-1) d.wt) in somatic embryos. Mature zygotic embryos that were removed from seeds and placed on medium in light rapidly accumulated phenolics in the embryonal root cap and hypocotyl. Delaying germination with ABA delayed phenolic compound accumulation, restricting it to the embryonal root cap.
  
  
  CONCLUSIONS
  In larch embryos, light has a negative effect on protein accumulation, but a positive effect on phenol accumulation. Light did not affect morphogenesis, e.g. cotyledon number. Somatic embryos produced different amounts of phenolics, such as quercetrin, depending on light conditions. The greatest difference was seen in the embryonal root cap in all embryo types and conditions.
authors.affiliation: Centre for Forest Biology, Department of Biology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 3N5, Canada, INRA, UR 0588 Research Unit on Breeding, Genetic and Physiology of Forest Trees, 2163 Avenue de la Pomme de pin CS 4001, Ardon, F- 45075 Orléans Cedex 2, France, Fachgebiet Obstbau, Technische Universität München, Dürnast 2, D-85354 Freising, Germany and INRA-Université Blaise Pascal, UMR_A 547 PIAF, Les Cézeaux, 24 Avenue des Landais, 63177 Aubière cedex, France pvonader@uvic.ca.
authors.forename: Patrick
authors.initials: P
authors.lastname: von Aderkas
authors.affiliation: Centre for Forest Biology, Department of Biology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 3N5, Canada, INRA, UR 0588 Research Unit on Breeding, Genetic and Physiology of Forest Trees, 2163 Avenue de la Pomme de pin CS 4001, Ardon, F- 45075 Orléans Cedex 2, France, Fachgebiet Obstbau, Technische Universität München, Dürnast 2, D-85354 Freising, Germany and INRA-Université Blaise Pascal, UMR_A 547 PIAF, Les Cézeaux, 24 Avenue des Landais, 63177 Aubière cedex, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Teyssier
authors.affiliation: Centre for Forest Biology, Department of Biology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 3N5, Canada, INRA, UR 0588 Research Unit on Breeding, Genetic and Physiology of Forest Trees, 2163 Avenue de la Pomme de pin CS 4001, Ardon, F- 45075 Orléans Cedex 2, France, Fachgebiet Obstbau, Technische Universität München, Dürnast 2, D-85354 Freising, Germany and INRA-Université Blaise Pascal, UMR_A 547 PIAF, Les Cézeaux, 24 Avenue des Landais, 63177 Aubière cedex, France.
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Charpentier
authors.affiliation: Centre for Forest Biology, Department of Biology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 3N5, Canada, INRA, UR 0588 Research Unit on Breeding, Genetic and Physiology of Forest Trees, 2163 Avenue de la Pomme de pin CS 4001, Ardon, F- 45075 Orléans Cedex 2, France, Fachgebiet Obstbau, Technische Universität München, Dürnast 2, D-85354 Freising, Germany and INRA-Université Blaise Pascal, UMR_A 547 PIAF, Les Cézeaux, 24 Avenue des Landais, 63177 Aubière cedex, France.
authors.forename: Markus
authors.initials: M
authors.lastname: Gutmann
authors.affiliation: Centre for Forest Biology, Department of Biology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 3N5, Canada, INRA, UR 0588 Research Unit on Breeding, Genetic and Physiology of Forest Trees, 2163 Avenue de la Pomme de pin CS 4001, Ardon, F- 45075 Orléans Cedex 2, France, Fachgebiet Obstbau, Technische Universität München, Dürnast 2, D-85354 Freising, Germany and INRA-Université Blaise Pascal, UMR_A 547 PIAF, Les Cézeaux, 24 Avenue des Landais, 63177 Aubière cedex, France.
authors.forename: Luc
authors.initials: L
authors.lastname: Pâques
authors.affiliation: Centre for Forest Biology, Department of Biology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 3N5, Canada, INRA, UR 0588 Research Unit on Breeding, Genetic and Physiology of Forest Trees, 2163 Avenue de la Pomme de pin CS 4001, Ardon, F- 45075 Orléans Cedex 2, France, Fachgebiet Obstbau, Technische Universität München, Dürnast 2, D-85354 Freising, Germany and INRA-Université Blaise Pascal, UMR_A 547 PIAF, Les Cézeaux, 24 Avenue des Landais, 63177 Aubière cedex, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Le Metté
authors.affiliation: Centre for Forest Biology, Department of Biology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 3N5, Canada, INRA, UR 0588 Research Unit on Breeding, Genetic and Physiology of Forest Trees, 2163 Avenue de la Pomme de pin CS 4001, Ardon, F- 45075 Orléans Cedex 2, France, Fachgebiet Obstbau, Technische Universität München, Dürnast 2, D-85354 Freising, Germany and INRA-Université Blaise Pascal, UMR_A 547 PIAF, Les Cézeaux, 24 Avenue des Landais, 63177 Aubière cedex, France.
authors.forename: Kevin
authors.initials: K
authors.lastname: Ader
authors.affiliation: Centre for Forest Biology, Department of Biology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 3N5, Canada, INRA, UR 0588 Research Unit on Breeding, Genetic and Physiology of Forest Trees, 2163 Avenue de la Pomme de pin CS 4001, Ardon, F- 45075 Orléans Cedex 2, France, Fachgebiet Obstbau, Technische Universität München, Dürnast 2, D-85354 Freising, Germany and INRA-Université Blaise Pascal, UMR_A 547 PIAF, Les Cézeaux, 24 Avenue des Landais, 63177 Aubière cedex, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Label
authors.affiliation: Centre for Forest Biology, Department of Biology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 3N5, Canada, INRA, UR 0588 Research Unit on Breeding, Genetic and Physiology of Forest Trees, 2163 Avenue de la Pomme de pin CS 4001, Ardon, F- 45075 Orléans Cedex 2, France, Fachgebiet Obstbau, Technische Universität München, Dürnast 2, D-85354 Freising, Germany and INRA-Université Blaise Pascal, UMR_A 547 PIAF, Les Cézeaux, 24 Avenue des Landais, 63177 Aubière cedex, France.
authors.forename: Lisheng
authors.initials: L
authors.lastname: Kong
authors.affiliation: Centre for Forest Biology, Department of Biology, University of Victoria, 3800 Finnerty Rd, Victoria, BC V8W 3N5, Canada, INRA, UR 0588 Research Unit on Breeding, Genetic and Physiology of Forest Trees, 2163 Avenue de la Pomme de pin CS 4001, Ardon, F- 45075 Orléans Cedex 2, France, Fachgebiet Obstbau, Technische Universität München, Dürnast 2, D-85354 Freising, Germany and INRA-Université Blaise Pascal, UMR_A 547 PIAF, Les Cézeaux, 24 Avenue des Landais, 63177 Aubière cedex, France.
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Lelu-Walter
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D018525:Germination / Q000187:drug effects / Q000528:radiation effects; D006824:Hybridization, Genetic; D028221:Larix / Q000187:drug effects / Q000196:embryology / Q000254:growth & development / Q000528:radiation effects*; D008027:Light; D010858:Pigmentation / Q000187:drug effects / Q000528:radiation effects*; D010937:Plant Growth Regulators / Q000494:pharmacology; D012639:Seeds / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects*
chemical_list: D010937:Plant Growth Regulators; D000040:Abscisic Acid
keywords: Larix × marschlinsii; cotyledon; embryonal root cap; larch; light response; phenolics; proteins; quercetrin; somatic embryogenesis; starch; zygotic embryogenesis