Fig. 4

Expression profiles of ZmNAAT, ZmDMAS, ZmTOM, and ZmENA genes in response to different iron levels. The maize seedlings were cultured to the three-leaf stage in standard Hoagland solution and then transferred to Hoagland solution with 0 or 500 μM Fe for deficiency (Fe--) and Fe excess (Fe++) treatments, respectively. The shoots (sh) and roots (root) were harvested at 0, 24, 48, and 96 h after treatments. Maize Actin1 was used to normalize relative gene expression. The error bars indicate standard deviations