Summary of statistical analysis (2- factor ANOVA and ANCOVA) comparing the effect of genotype and N availability on the ecophysiological variables.

Leaf area (cm2), total biomass (g), root∶total biomass ratio, radiation use efficiency (RUE) (g of biomass MJ−1 of PAR intercepted), rhizodeposition (µ C s−1 g−1 of root), nitrogen nutritional index (NNI), total amount of N (mg plant−1), specific nitrogen uptake (SNU) (g of N g−1 of root biomass) and conversion factor of nitrogen to leaf area (NLA) (cm2 of leaves g−1 of N).
Significance of ANOVA: ns, *, ** and *** indicate not significant and significant levels of 0.05, and 0.01 and 0.001 respectively.