Two-predictor polynomial curves describing how the PSII-inhibiting effect of elevated temperature changed with increasing diuron concentrations.

Inclusion of a second order polynomial term for concentration (Conc2) did not improve fit for any of the models (ANOVA test for model comparison) and was excluded from the model. Equations linking temperature and diuron concentration were fitted to the inhibition data and solved to obtain temperatures where 10 and 25% inhibition ΔF/F′m and Fv/Fm occurred (IT10 and IT25, respectively). The adjusted R2 indicates which part of the variance in the dataset is explained by the model. Empty fields signify diuron concentrations at which >10 or 25% inhibition PSII yield was observed, irrespective of temperature. T = temperature (°C), Conc = diuron concentration (µg L−1).