title: Pre-exposure to nitric oxide modulates the effect of ozone on oxidative defenses and volatile emissions in lima bean.
abstract: The roles that ozone and nitric oxide (NO), the chief O₃ precursor, play in the antioxidative balance and inducible volatile emissions of lima bean were assessed. Exposure to O₃ inhibited APX, CAT, and GR, decreased GSH content and induced emissions of (E)-β-ocimene, limonene, 1,8-cineole, linalool, (E)-4,8-dimethyl-1,3,7-nonatriene (E)-DMNT, 2-butanone and nonanal. O₃ did not induce emissions of (E)-β-caryophyllene and appeared to reduce the antioxidative capacity of plants to a greater extent than NO and NO followed by O₃ (NO/O₃) treatments. There were significant differences in emissions of (E)-β-ocimene and linalool between NO/O₃ treated plants and controls, but no differences in antioxidant concentrations. A model to explain the relationships between the ascorbate-glutathione cycle and O₃ and NO inducible volatiles was proposed. Our findings suggest that prior exposure to NO modulates the oxidative effect of ozone by the process of cross-tolerance, which might regulate the antioxidative system and induction of volatile organic compounds.
authors.affiliation: Department of Environmental Science, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland. souzasrd@gmail.com
authors.forename: Silvia R
authors.initials: SR
authors.lastname: Souza
authors.forename: James D
authors.initials: JD
authors.lastname: Blande
authors.forename: Jarmo K
authors.initials: JK
authors.lastname: Holopainen
mesh_terms: D000393:Air Pollutants / Q000378:metabolism / Q000633:toxicity*; D060387:Ascorbate Peroxidases / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D010126:Ozone / Q000378:metabolism / Q000633:toxicity*; D027805:Phaseolus / Q000187:drug effects / Q000502:physiology*; D013729:Terpenes / Q000032:analysis* / Q000378:metabolism; D055549:Volatile Organic Compounds / Q000032:analysis* / Q000378:metabolism
chemical_list: D000393:Air Pollutants; D013729:Terpenes; D055549:Volatile Organic Compounds; D009569:Nitric Oxide; D010126:Ozone; D060387:Ascorbate Peroxidases; D002374:Catalase; D005980:Glutathione Reductase; D005978:Glutathione