Effect of P deficiency on AtPT2 gene expression (A) and Fe deficiency on ferric reductase activity (B) in Arabidopsis wild-type (WT) Columbia-0 plants and ethylene mutants (ctr1, ethylene-constitutive mutant; ein2, ethylene-insensitive mutant; eto1, ethylene overproducer mutant). Fold changes were normalized to transcript levels of the wild type on P sufficiency (A) and ferric reductase activity of the wild type on Fe sufficiency (B). Data for P treatments were redrawn from Lei et al. (2011) with permission, and data for Fe were from García et al. (2010, 2014) and M.J. García, F.J. Romera, C. Lucena, E. Alcántara, and R. Pérez-Vicente (unpublished data).