Figure 4

2-DE maps. Representative 2-DE maps of soluble protein fractions extracted from roots (A) and leaves (B) of Zea mays plants. Proteins (400 μg) were analyzed by IEF at pH 3–10, followed by 12.5% SDS-PAGE and visualized by cCBB-staining. Name abbreviations, corresponding to those in Tables 2 and 3, indicate the spots, identified by LC-ESI-MS/MS, showing significant changes of at least two-fold in their relative volumes (t-test, p < 0.05) after the exposure to 10 mM nitrate for 30 h. Proteins that increased or decreased after this treatment are reported in blue or in red, respectively.