Nodulated root phenotypic traits of soybean plants grown for 15 d either under well-watered conditions (C), or subjected to a water deficit with (WS+NF) or without (WS) NF supply in the nutrient solution. Phenotypic traits comprised: root length (A), number of root tips (B), nodule number (C), nodule biomass (D), nodule specific activity (E), and the total amount of N symbiotically fixed per plant (F). Error bars represent standard deviation (n = 10), and differences among treatments significant at the 0.05 probability level, are denoted by different letters.