Fig. 3. a) Norm of reaction plots illustrating the effects of ploidy level and defoliation on net photosynthesis (mean ± SE) in well-watered trees. The left panel represents values averaged across genotypes from the same ploidy level when defoliated or not defoliated. Model results above the left panel do not account for genotypic variation. The right panel represents mean response of eight different diploid and triploid genotypes when defoliated or not defoliated. Identical genotypes of both defoliation treatments are shown next to each other with identical color shades. Model results above the right panel account for genotypic variation. Only values of model variables with P ≤ 0.100 are shown. Data points are horizontally jittered to reduce overlapping. b) Photosynthesis vulnerability curves of defoliated and undefoliated diploid and triploid genotypes. Red trends were generated based on back-transformed means of ln-transformed genotype values for each of the curve-fitting parameters (A max, b and c ). Transformation of genotype parameters lessened the undue influence of outlier values. Thin curves represent untransformed, individual genotypes. The impact of ploidy, defoliation and their interaction on the curve parametersA max, b and c was tested in models accounting for genotypic differences. Only values of model variables with P ≤ 0.100 are shown.