FIGURE 6.

Time course expression analysis of PM H⁺-ATPase genes in ${\mathrm{NO}}_{\mathrm{3}}^{\mathrm{–}}$-induced maize roots. The expression levels of GRMZM2G006894_T01 (ZmHA4), GRMZM2G035520_T01, GRMZM2G148374_T01, GRMZM2G104325_T01 and GRMZM2G019404_T01 (ZmHA2) were assessed by qRT–PCR in maize roots treated for the indicated times with ${\mathrm{NO}}_{\mathrm{3}}^{\mathrm{–}}$. The data were normalized to two internal controls, elongation factor 1-alpha (GRMZM2G153541_T01) and polyubiquitin containing seven ubiquitin monomers (GRMZM2G118637_T01). The relative expression ratios were calculated using untreated control roots as a calibrator sample. The values reported are means ± SE; n = 3 (^∗P < 0.05; ^∗∗P < 0.01; ^∗∗∗P < 0.001).