Interactive effects of elevated CO2, ozone and drought stress on the activities of antioxidative enzymes in needles of Norway spruce trees (Picea abies, [L.] Karsten) grown with luxurious N-supply

abonos nitrogenados azote carbon dioxide catalasa catalase crecimiento croissance dioxyde de carbone enzimas enzyme enzymes enzymic activity estres feuille fichte growth hojas leaves nitrogen nitrogen fertilizers ozone ozono peroxidases picea abies stress superoxide dismutase superoxyde dismutase trockenstress