title: Differential requirement for NO during ABA-induced stomatal closure in turgid and wilted leaves.
abstract: Abscisic acid (ABA)-induced stomatal closure is mediated by a complex, guard cell signalling network involving nitric oxide (NO) as a key intermediate. However, there is a lack of information concerning the role of NO in the ABA-enhanced stomatal closure seen in dehydrated plants. The data herein demonstrate that, while nitrate reductase (NR)1-mediated NO generation is required for the ABA-induced closure of stomata in turgid leaves, it is not required for ABA-enhanced stomatal closure under conditions leading to rapid dehydration. The results also show that NO signalling in the guard cells of turgid leaves requires the ABA-signalling pathway to be both capable of function and active. The alignment of this NO signalling with guard cell Ca(2+)-dependent/independent ABA signalling is discussed. The data also highlight a physiological role for NO signalling in turgid leaves and show that stomatal closure during the light-to-dark transition requires NR1-mediated NO generation and signalling.
authors.affiliation: Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Minas Gerais, Brazil.
authors.forename: Dimas M
authors.initials: DM
authors.lastname: Ribeiro
authors.forename: Radhika
authors.initials: R
authors.lastname: Desikan
authors.forename: Jo
authors.initials: J
authors.lastname: Bright
authors.forename: Ana
authors.initials: A
authors.lastname: Confraria
authors.forename: Judith
authors.initials: J
authors.lastname: Harrison
authors.forename: John T
authors.initials: JT
authors.lastname: Hancock
authors.forename: Raimundo S
authors.initials: RS
authors.lastname: Barros
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Neill
authors.forename: Ian D
authors.initials: ID
authors.lastname: Wilson
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D029681:Arabidopsis Proteins / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D008027:Light; D009154:Mutation; D050901:Nitrate Reductase / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism*; D054046:Plant Stomata / Q000378:metabolism* / Q000502:physiology; D014867:Water / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins; D010937:Plant Growth Regulators; D014867:Water; D009569:Nitric Oxide; D000040:Abscisic Acid; D050901:Nitrate Reductase; D002118:Calcium