Is stimulation of leaf photosynthesis by elevated carbon dioxide concentration maintained in the long term? A test with Lolium perenne grown for 10 years at two nitrogen fertilization levels under Free Air CO2 Enrichment (FACE). - Ainsworth,E..A..; Davey,P..A..; Hymus,G..J..; Osborne,C..P..; Rogers,A..; Blum,H..; Nosberger,J..; Long,S..P.. (Plant, Cell and Environment, 2003)