Photosynthetic functions in Arabidopsis thaliana in different growth regimes. Plants were grown in climate chambers under Low, Normal or High Light (LL, NL and HL; 30, 300 and 600 μmol quanta m-2 s-1, respectively) and under field conditions. Photosynthetic function was assessed in dark-adapted leaves. Light response curves are shown for (A) Fv/Fm (B) non-photochemical quenching (NPQ) and (C) qP. Data represent means ± SE for leaves from at least six plants grown in two batches. Different lower case letters above bars indicate significant differences (p < 0.001), according to separate Duncan's new multiple range tests followed by contrast analysis (indoor vs. field plants) applied to data presented in each column.