TY  - JOUR
A1  - Streb, Peter
A1  - Schaub, Hermann
A1  - Feierabend, Jürgen
T1  - Latent oxidative stress responses of ozone-fumigated cucumber plants are enhanced by simultaneous cold exposures
T2  - Zeitschrift für Naturforschung, C
N2  - Cucumber plants (Cucumis sativus L.) were grown under controlled conditions and fumigated with either O3, diluted automobile exhaust or a combination of both. The ratio of variable to maximum chlorophyll fluorescence (Fv/Fm) was estimated as a measure of PSII activity Activities of the enzymes catalase, glutathione reductase and guaiacol-dependent peroxidase and contents of the antioxidants ascorbate and glutathione were assayed as potential 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 additional 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 of the Fv/Fm 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 O3-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.
KW  - Cucumis sativus (Cucumber)
KW  - Automobile Exhaust
KW  - Latent Injury
KW  - Oxidative Stress
KW  - Ozone
Y1  - 2014
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/79940
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-799400
SN  - 0939-5075
SN  - 1865-7125
VL  - 51.1996
IS  - 5-6
SP  - 355
EP  - 362
PB  - Verlag der Zeitschrift für Naturforschung
CY  - Tübingen
ER  -