Growth, respiration and nitrogen content in needles of Scots pine exposed to elevated ozone and carbon dioxide in the field

air pollution atmosfera atmosphere azote carbon dioxide carbon dioxide enrichment chemical composition composition chimique crecimiento croissance dioxyde de carbone enrichissement en gaz carbonique feuille growth hojas leaves metabolism metabolisme metabolismo nitrogen nitrogen content nutrition des plantes nutrition physiology ozone ozono physiologie de la nutrition pinus sylvestris plant nutrition respiration teneur en azote