Fig. 3. Ratio of mitochondrial rates of pyruvate oxidation to maximal activities of cytochrome c oxidase (CCO) and citrate synthase (CS) during warm and cold acclimation. Values are expressed per mU CCO and per mU CS. Data are means ± S.E.M. When values at a given assay temperature during each acclimation experiment differ, they are followed by different letters (P0.05; ANOVA and Tukey's a posteriori test). The number of individuals in each experiment is shown in Table 1.