Quantitative comparison of freezing damage to detached Arabidopsis leaves determined by chlorophyll fluorescence imaging (FV/FM; compare Fig. 1) and electrolyte leakage measurements. The corresponding false color chlorophyll fluorescence images are shown in Fig. 4. Leaves were either imaged directly after thawing (IPAM no incubation), or after 24 h of incubation in distilled water at 4°C (IPAM 24 h incubation and EL 24 h incubation). Error bars denote the SEM from three replicate measurements. The FV/FM axis has been inverted to allow comparison with the electrolyte leakage data.