title: EPR spectroscopy as a tool for investigation of differences in radical status in wheat plants of various tolerances to osmotic stress induced by NaCl and PEG-treatment.
abstract: Two kinds of wheat genotypes with different tolerance to osmotic stress (NaCl and PEG-treatment) were investigated with biochemical analyses, including the measurements of total antioxidant capacity, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, reducing power and starch content. The results were compared with electron paramagnetic resonance (EPR) data concerning the nature and amounts of stable long lived radicals present in the control and stressed plants. In addition, the changes in manganese content upon stress conditions were monitored. Different mechanisms of protection against PEG stress in sensitive and tolerant wheat genotypes were postulated. In sensitive genotypes, electrons were created in excess in stress conditions, and were stabilized by polysaccharide molecules, whereas in tolerant genotypes, protection by antioxidants dominated. Moreover, the quinone-semiquinone balance shifted towards semiquinone, which became the place of electron trapping. NaCl-treatment yielded significant effects mainly in sensitive genotypes and was connected with the changes of water structure, leading to inactivation of reactive oxygen species by water molecules.
authors.affiliation: Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland. labanows@chemia.uj.edu.pl
authors.forename: Maria
authors.initials: M
authors.lastname: Labanowska
authors.forename: Maria
authors.initials: M
authors.lastname: Filek
authors.forename: Magdalena
authors.initials: M
authors.lastname: Kurdziel
authors.forename: Ewa
authors.initials: E
authors.lastname: Bidzińska
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Miszalski
authors.forename: Hélina
authors.initials: H
authors.lastname: Hartikainen
mesh_terms: D000222:Adaptation, Physiological; D000975:Antioxidants / Q000378:metabolism*; D055864:Droughts; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000378:metabolism*; D014644:Genetic Variation; D005838:Genotype; D009997:Osmotic Pressure; D011044:Poland; D011092:Polyethylene Glycols; D054712:Salinity; D012965:Sodium Chloride / Q000378:metabolism*; D013312:Stress, Physiological; D014908:Triticum / Q000378:metabolism*; D014867:Water / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D005609:Free Radicals; D014867:Water; D011092:Polyethylene Glycols; D012965:Sodium Chloride