Figure 2.

Root architecture phenotypes of A17 and sunn-1 seedlings. Nodule density (A), first-order lateral root density (B), and lateral root length (total of all lateral roots per plant; C) of 20-d-old cv Jemalong A17 and sunn-1 seedlings grown in ambient C (370 μL L⁻¹ CO₂ [C₃₇₀]), high C (800 μL L⁻¹ CO₂ [C₈₀₀]), minus N (0 mm nitrate [N₀]), and/or plus N (2.5 mm nitrate [N_2.5]) are shown. Inoculation with S. meliloti was performed on 5-d-old seedlings. Data are results from four samples of six to eight seedlings each ± se. Treatments labeled with different letters differ significantly within one genotype (P < 0.05; two-way ANOVA).