title: Redox changes during cold acclimation affect freezing tolerance but not the vegetative/reproductive transition of the shoot apex in wheat.
abstract: Cold acclimation is necessary for winter wheat (Triticum aestivum L.) to achieve its genetically determined maximum freezing tolerance, and cold also fulfils the vernalisation requirement. Chromosome 5A is a major regulator of these traits. The aim of the present study was to discover whether changes in the half-cell redox potential of the glutathione/glutathione disulphide (GSH/GSSG) and ascorbate/dehydroascorbate (AA/DHA) couples induced by cold acclimation are related to freezing tolerance and vernalisation requirement in a specific genetic system including chromosome 5A substitution lines. The amounts of H₂O₂ and AA, and the AA/DHA ratio showed a rapid and transient increase in the crown of all genotypes during the first week of acclimation, followed by a gradual increase during the subsequent 2 weeks. The amount of GSH and its ratio compared to GSSG quickly decreased during the first day, while later these parameters showed a continuous slow increase. The H₂O₂, AA and GSH concentrations, AA/DHA and GSH/GSSG ratios and the half-cell reduction potential of the GSH/GSSG couple were correlated with the level of freezing tolerance after 22 days at 2 °C; hence these parameters may have an important role in the acclimation process. In contrast to H₂O₂ and the non-enzymatic antioxidants, the lipid peroxide concentration and activity of the four antioxidant enzymes exhibited a transient increase during the first week, with no significant difference between genotypes. None of the parameters studied showed any relationship with the vegetative/generative transition state monitored as apex morphology and vernalisation gene expression.
authors.affiliation: Agricultural Research Institute of the Hungarian Academy of Sciences, Martonvásár, Hungary.
authors.forename: A
authors.initials: A
authors.lastname: Soltész
authors.forename: I
authors.initials: I
authors.lastname: Tímár
authors.forename: I
authors.initials: I
authors.lastname: Vashegyi
authors.forename: B
authors.initials: B
authors.lastname: Tóth
authors.forename: T
authors.initials: T
authors.lastname: Kellos
authors.forename: G
authors.initials: G
authors.lastname: Szalai
authors.forename: A
authors.initials: A
authors.lastname: Vágújfalvi
authors.forename: G
authors.initials: G
authors.lastname: Kocsy
authors.forename: G
authors.initials: G
authors.lastname: Galiba
mesh_terms: D000064:Acclimatization / Q000235:genetics / Q000502:physiology*; D000975:Antioxidants / Q000378:metabolism; D003080:Cold Temperature; D018506:Gene Expression Regulation, Plant; D010084:Oxidation-Reduction; D018520:Plant Shoots / Q000254:growth & development; D012621:Seasons; D014908:Triticum / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism
chemical_list: D000975:Antioxidants