Free-air CO2 enrichment of wheat: leaf flavonoid concentration throughout the growth cycle. - Estiarte,M..; Peñuelas,J..; Kimball,B..A..; Hendrix,D..L..; Pinter,P..J..; Wall,G..W..; LaMorte,R..L..; Hunsaker,D.. (Physiologia Plantarum, 1999)