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1996 (1)
1Author    Peter Streb, Ann Herm, Jürgen Schaub, FeierabendRequires cookie*
 Title    Latent Oxidative Stress Responses of Ozone-Fumigated Cucumber Plants Are Enhanced by Simultaneous Cold Exposures  
 Abstract    Cucumber plants (Cucumis sativus L.) were grown under controlled conditions and fumi­ gated with either 0 3, diluted autom obile exhaust or a combination of both. The ratio of variable to maximum chlorophyll fluorescence (FJFm) was estimated as a measure of PSII activity Activities of the enzymes catalase, glutathione reductase and guaiacol-dependent peroxidase and contents o f the antioxidants ascorbate and glutathione were assayed as poten­ tial indicators of oxidative stress. The behavior of catalase and of PSII are of particular diagnostic interest because they require continuous repair in light. Exposures of up to 13 days to moderate concentrations of the pollutant gases alone did not induce striking changes in any of the activities that were assayed. A lso when the plants were subjected to an addi­ tional stress treatment by exposing them to 4 short cold treatments (2h each at 0 -4 °C in light on days 12-15 after sowing) which induced marked declines o f the FJFm ratio, the chlorophyll content and the catalase activity, these cold-induced symptoms of photodamage were not significantly enhanced by the fumigation treatments. However, increases of the activities of glutathione reductase and peroxidase observed during a period of recovery following the cold-exposures were markedly higher in 0 3-fumigated plants, as compared to plants grown in filtered air or fumigated with car exhaust alone. The results emphasize that effects of moderate pollutant exposures may be latent or delayed over long time periods and that defence responses can be enhanced when plants are exposed to additional, naturally occurring stress situations. 
  Reference    Z. Naturforsch. 51c, 355 (1996); received January 26/February 23 1996 
  Published    1996 
  Keywords    Cucumis sativus (Cucumber), Autom obile Exhaust, Latent Injury, Oxidative Stress, Ozone 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0355.pdf 
 Identifier    ZNC-1996-51c-0355 
 Volume    51