Fig. 3.

Photoinhibition at 22 °C (a) or at 4 °C (b, c) in the presence of lincomycin, quantified by the light-saturated oxygen evolution of PSII in the presence of an artificial electron acceptor. PSII activity was measured from thylakoid membranes isolated from leaves of four non-cold-treated (NT; a, b) or cold-treated (CT; c) A. thaliana accessions, at different time points during the 45-min illumination (PPFD 2000 µmol m⁻² s⁻¹). The error bars show SD from at least four biological replicates. The lines show a fit to the first order reaction equation. The control values in µmol O₂ (mg chlorophyll)⁻¹ h⁻¹ (± SD) were 160 (37.5), 162 (26.4), 180 (20.2) and 132 (31.2) for Rschew, Tenela, Columbia-0 and Coimbra, respectively, in a, 169 (67.6), 148 (67.1), 162 (37.4) and 135 (24.7) in b and 210 (21.7), 186 (22.9), 164 (28.7) and 162 (37) in c