Objectif The project aims at evaluating the environmental impact of large emissions of nitrogen oxides into the environment concerning effects on growth, senescence processes and cellular injury in trees (poplar, pine and spruce).In many forests throughout Europe, trees are exposed to increasing concentrations of ozone and hydroperoxides together with elevated inputs of nitrogen. Free radical production and/or formation of hydroperoxides, from reactions between ozone and unsaturated hydrocarbons produced in plants, are suspected to be responsible for the phytotoxicity of ozone. In both long-term and short-term experiments with poplar and pine, this will be examined for reaction products of these reactions, formation of free radicals, aldehydes and monocarbonic acids, and the expression of the antioxidant enzymes, ascorbate peroxidase, glutathione reductase, superoxide dismutase, catalase and their regulation by the phytohormone ethylene. In these experiments, plants will also be subjected to different levels of nitrogen to investigate imbalancing of other nutrients and how the toxicity of ozone and/or hydrogen peroxide may be modified. In these experiments, iron, manganese and/or zinc will be of special interest, as these trace nutrients are essential constituents of these antioxidant enzymes and necessary for their functioning. How they also protect plants against exposure to ambient concentrations of ozone and/or hydroperoxides will be assessed in plants deficient in these elements. Finally, these results will be compared with those exposed to organic hydroperoxides as these have also been reported to be inhibitory to these enzymes. Furthermore, these effects of ozone will also be assessed in the presence or absence of low concentrations of NO (2-5 ppb) as the presence of such low concentrations of NO have been suggested to be required for ozone toxicity. Champ scientifique sciences naturellessciences chimiqueschimie organiquealdéhydesciences naturellessciences chimiqueschimie inorganiquemétal de transitionsciences naturellessciences chimiqueschimie organiquehydrocarburessciences naturellessciences chimiqueschimie organiquecomposés aliphatiquessciences naturellessciences biologiquesbiochimiebiomoléculeprotéinesenzyme Programme(s) FP3-ENV 1C - Specific research and technological development programme (EEC) in the field of the environment, 1990-1994 Thème(s) 0106 - Biogeochemical cycles and ecosystem dynamics Appel à propositions Data not available Régime de financement CSC - Cost-sharing contracts Coordinateur Universität Gesamthochschule Essen Adresse Henry-dunant-straße 65 45131 Essen Allemagne Voir sur la carte Contribution de l’UE Aucune donnée Participants (3) Trier par ordre alphabétique Trier par contribution de l’UE Tout développer Tout réduire Eidgenössische Forschungsanstalt für Agrikulturchemie und Umwelthygiene Suisse Contribution de l’UE € 0,00 Adresse 155,schwarzenburgstrasse 3097 Liebefeld-bern Voir sur la carte Autres sources de financement Aucune donnée THE PROVOST, FELLOWS AND SCHOLARS OF THE COLLEGE OF THE HOLY AND UNDIVIDED TRINITY OF QUEEN ELIZABETH NEAR DUBLIN HEREINAFTER TRINITY COLLEGE DUBLIN Irlande Contribution de l’UE € 0,00 Adresse College green 2 Dublin Voir sur la carte Autres sources de financement Aucune donnée UNIVERSITY OF LANCASTER Royaume-Uni Contribution de l’UE € 0,00 Adresse Bailrigg LA1 4YQ Lancaster /high bantham Voir sur la carte Autres sources de financement Aucune donnée
