title: Abscisic acid regulates seed germination of Vellozia species in response to temperature.
abstract: The relationship between the phytohormones, gibberellin (GA) and abscisic acid (ABA) and light and temperature on seed germination is still not well understood. We aimed to investigate the role of the ABA and GA on seed germination of Vellozia caruncularis, V. intermedia and V. alutacea in response to light/dark conditions on different temperature. Seeds were incubated in GA (GA3or GA4) or ABA and their respective biosynthesis inhibitors (paclobutrazol - PAC, and fluridone - FLU) solutions at two contrasting temperatures (25 and 40 °C). Furthermore, endogenous concentrations of active GAs and those of ABA were measured in seeds of V. intermedia and V. alutacea during imbibition/germination. Exogenous ABA inhibited the germination of Vellozia species under all conditions tested. GA, FLU and FLU + GA3stimulated germination in the dark at 25 °C (GA4being more effective than GA3). PAC reduced seed germination in V. caruncularis and V. alutacea, but did not affect germination of V. intermedia at 40 °C either under light or dark conditions. During imbibition in the dark, levels of active GAs decreased in the seeds of V. intermedia, but were not altered in those of V. alutacea. Incubation at 40 °C decreased ABA levels during imbibition in both V. caruncularis and V. alutacea. We conclude that the seeds of Vellozia species studied here require light or high temperature to germinate and ABA has a major role in the regulation of Vellozia seed germination in response to light and temperature.
authors.affiliation: Departamento de Botânica, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: B C
authors.initials: BC
authors.lastname: Vieira
authors.affiliation: Departamento de Botânica, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: E M
authors.initials: EM
authors.lastname: Bicalho
authors.affiliation: Departamento de Biologia Vegetal, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Munné-Bosch
authors.affiliation: Departamento de Botânica, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Q S
authors.initials: QS
authors.lastname: Garcia
mesh_terms: D000040:Abscisic Acid / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D003624:Darkness; D018506:Gene Expression Regulation, Plant; D018525:Germination / Q000187:drug effects*; D005875:Gibberellins / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D006358:Hot Temperature; D008027:Light; D019684:Magnoliopsida / Q000187:drug effects* / Q000502:physiology / Q000528:radiation effects; D010937:Plant Growth Regulators / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011728:Pyridones / Q000494:pharmacology; D012639:Seeds / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D014230:Triazoles / Q000494:pharmacology
chemical_list: D005875:Gibberellins; D010937:Plant Growth Regulators; D011728:Pyridones; D014230:Triazoles; C013351:fluridone; C053370:paclobutrazol; D000040:Abscisic Acid
keywords: Abscisic acid; Velloziaceae; dark; fluridone; gibberellins; paclobutrazol