title: Germination induction of dormant Avena fatua caryopses by KAR(1) and GA(3) involving the control of reactive oxygen species (H2O2 and O2(·-)) and enzymatic antioxidants (superoxide dismutase and catalase) both in the embryo and the aleurone layers.
abstract: Avena fatua L. caryopses did not germinate at 20 °C in darkness because they were dormant. However, they were able to germinate in the presence of karrikinolide (KAR1), a key bioactive compound present in smoke, and also in the presence of gibberellin A3 (GA3), a commonly known stimulator of seed germination. The aim of this study was to collect information on a possible relationship between the above regulators and abscisic acid (ABA), reactive oxygen species (ROS) and ROS scavenging antioxidants in the regulation of dormant caryopses germination. KAR1 and GA3 caused complete germination of dormant A. fatua caryopses. Hydrogen peroxide (H2O2), compounds generating the superoxide (O2(·-)), i.e. menadione (MN), methylviologen (MV) and an inhibitor of catalase activity, aminotriazole (AT), induced germination of dormant caryopses. KAR1, GA3, H2O2 and AT decreased ABA content in embryos. Furthermore, KAR1, GA3, H2O2, MN, MV and AT increased α-amylase activity in caryopses. The effect of KAR1 and GA3 on ROS (H2O2, O2(·-)) and activities of the superoxide dismutase (SOD) and catalase (CAT) were determined in caryopses, embryos and aleurone layers. SOD was represented by four isoforms and catalase by one. In situ localization of ROS showed that the effect of KAR1 and GA3 was associated with the localization of hydrogen peroxide mainly on the coleorhiza. However, the superoxide was mainly localized on the surface of the scutellum. Superoxide was also detected in the protruding radicle. Germination induction of dormant caryopses by KAR1 and GA3 was related to an increasing content of H2O2, O2(·-)and activities of SOD and CAT in embryos, thus ROS homeostasis was probably required for the germination of dormant caryopses. The above regulators increased the content of ROS in aleurone layers and decreased the activities of SOD and CAT, probably leading to the programmed cell death. The presented data provide new insights into the germination induction of A. fatua dormant caryopses by KAR1 and also by GA3. In A. fatua, KAR1 or GA3 is included in the induction germination of dormant caryopses through regulation level of ABA in embryos and ROS-antioxidant status both in embryos and aleurone layers.
authors.affiliation: Department of Plant Physiology and Genetic Engineering, Faculty of Biology, University of Szczecin, Wąska 13, 71-415 Szczecin, Poland.
authors.forename: Danuta
authors.initials: D
authors.lastname: Cembrowska-Lech
authors.affiliation: Department of Heteroorganic Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Łódź, Poland.
authors.forename: Marek
authors.initials: M
authors.lastname: Koprowski
authors.affiliation: Department of Plant Physiology and Genetic Engineering, Faculty of Biology, University of Szczecin, Wąska 13, 71-415 Szczecin, Poland. Electronic address: jankepcz@wp.pl.
authors.forename: Jan
authors.initials: J
authors.lastname: Kępczyński
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000640:Amitrole / Q000494:pharmacology; D000975:Antioxidants / Q000378:metabolism*; D018554:Avena / Q000187:drug effects / Q000196:embryology* / Q000201:enzymology; D002374:Catalase / Q000037:antagonists & inhibitors / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005663:Furans / Q000494:pharmacology*; D018525:Germination / Q000187:drug effects*; D005875:Gibberellins / Q000494:pharmacology*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009861:Onium Compounds / Q000494:pharmacology; D010269:Paraquat / Q000494:pharmacology; D057445:Plant Dormancy / Q000187:drug effects*; D011714:Pyrans / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012639:Seeds / Q000187:drug effects / Q000196:embryology* / Q000201:enzymology; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D024483:Vitamin K 3 / Q000494:pharmacology; D000516:alpha-Amylases / Q000378:metabolism
chemical_list: D000975:Antioxidants; D004791:Enzyme Inhibitors; D005663:Furans; D005875:Gibberellins; D009861:Onium Compounds; D011714:Pyrans; D017382:Reactive Oxygen Species; C557869:karrikinolide; D013481:Superoxides; C007517:diphenyleneiodonium; D024483:Vitamin K 3; D000040:Abscisic Acid; D006861:Hydrogen Peroxide; C007842:gibberellic acid; D002374:Catalase; D013482:Superoxide Dismutase; D019255:NADPH Oxidases; D000516:alpha-Amylases; D010269:Paraquat; D000640:Amitrole
keywords: Abscisic acid; Avena fatua; Caryopses germination; Karrikinolide; Reactive oxygen species