P, N and K concentrations in stems of wildtype and transgenic poplar (P. × canescens).

CCR, COMT and CAD refer to transgenic poplar lines with suppressed activities of cinnamoyl coenzyme A reductase, caffeic acid O-methyl transferase, and cinnamyl alcohol dehydrogenase, respectively. F statistics and p-values are given for one-way ANOVA (p≤0.05). Significant differences between poplar lines are indicated by different letters. Data indicate means ± SE (L22: n = 4, all other n = 7–9). NA = not available.