Main and interactive effects of nitrogen, genotype, and tannin group.

ANOVA summary testing growth and tissue chemistry traits of Populus tremula plants in response to nitrogen addition (N), tannin group (Tgr), genotype nested within tannin group (GT(Tgr)), and interactions thereof. F-values are followed by significance levels:***P**P*PDegrees of freedom (df) for the numerator are indicated in subscript. Denominator df were always 150, unless the block effectb was significant, and included into the analysis, which reduced the denominator df to 148.Main and interactive effects of nitrogen, genotype, and tannin group.