Fig. 3From: Humic acids and Herbaspirillum seropedicae change the extracellular H+ flux and gene expression in maize roots seedlingsRelative mRNA expression of the a low-affinity nitrate transporter (Nrt2.1) and b high-affinity nitrate transporter (Nrt1.1) genes in maize roots treated or untreated with 50 mg C L−1 humic acid (HA), H. seropedicae (Bac) or 50 mg C L−1 humic acid and H. seropedicae (HA + Bac) for 7 days in hydroponic culture. mRNA levels were normalized in relation to the control gene (ubiquitin). The error was calculated by the REST® programBack to article page