Fig. 1From: Nitrate/ammonium-responsive microRNA-mRNA regulatory networks affect root system architecture in Populus × canescensMorphological parameters of P. × canescens roots treated with different N forms for 21 days. Phenotypes of P. × canescens cultured with 1 mM NO3−, 500 μM NH4 NO3 or 1 mM NH4+ for 21 days (a). Root length (b), lateral root initiation (c) and lateral root density (d). Data are presented as the mean ± SEs (n = 18). a, b and c indicate significant differences based on one-way ANOVA and Duncan’s test (P < 0.05)Back to article page