title: Antioxidant enzymes and DPPH-radical scavenging activity in chilled and heat-shocked rice (Oryza sativa L.) seedlings radicles.
abstract: Chilling whole rice seedlings at 5 degrees C significantly increased the time needed to recover linear growth and reduced the subsequent linear rate of radicle growth. Subjecting nonchilled seedlings to a 45 degrees C heat shock for up to 20 min did not alter subsequent growth, whereas a 3 min heat shock was optimal in reducing growth inhibition caused by 2 days of chilling. The activity of five antioxidant enzymes [superoxide dismutase (EC 1.15.1.1), catalase (CAT; EC 1.11.1.6), ascorbate peroxidase (APX; EC 1.11.1.11), glutathione reductase (GR; EC 1.6.4.2), and guaiacol peroxidase (GPX; EC 1.11.1.7)] and DPPH (1,1-diphenyl-2-picrylhydrazyl)-radical scavenging activity were measured in heat-shocked and/or chilled radicles. Heat shock slightly increased the activity of CAT, APX, and GR and suppressed the increase of GR and GPX activity during recovery from chilling. Increased CAT, APX, GR, and DPPH-radical scavenging activity and protection of CAT activity during chilling appear to be correlated with heat shock-induced chilling tolerance.
authors.affiliation: Mann Laboratory, Department of Vegetable Crops, University of California, One Shields Avenue, Davis, CA 95616-8631, USA.
authors.forename: Ho-Min
authors.initials: HM
authors.lastname: Kang
authors.forename: Mikal E
authors.initials: ME
authors.lastname: Saltveit
mesh_terms: D060387:Ascorbate Peroxidases; D015764:Bepridil / Q000031:analogs & derivatives* / Q000378:metabolism*; D001713:Biphenyl Compounds; D002374:Catalase / Q000378:metabolism; D016166:Free Radical Scavengers / Q000378:metabolism*; D005609:Free Radicals / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D006358:Hot Temperature; D012275:Oryza / Q000201:enzymology* / Q000254:growth & development; D009195:Peroxidase / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D010851:Picrates; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D005609:Free Radicals; D010851:Picrates; D015764:Bepridil; C004931:1,1-diphenyl-2-picrylhydrazyl; D010544:Peroxidases; C121048:guaiacol peroxidase; D060387:Ascorbate Peroxidases; D002374:Catalase; D009195:Peroxidase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase