Fig. 4.

Complementation study and expression analysis of putative target genes. (A) Arabidopsis wild-type plants (WT), double T-DNA insertion mutants (m19m23), and double mutants constitutively expressing either bZIP19 (m19m23-OX19) or bZIP23 (m19m23-OX23), grown for 3 weeks in MS medium without (Zn-) and with 30 μM ZnSO₄ (Zn+). (B) Relative transcript levels (RTL) of ZIP4, ZIP1, ZIP3, ZIP5, ZIP9, ZIP12, IRT3, and ZIP2 in 3-week-old wild-type seedlings of Arabidopsis (WT) (white bars) and m19m23 double mutants (gray bars) grown in MS medium with 30 μM ZnSO₄ (Zn+) or without (Zn-) (mean ± SEM).