nac4-2 and szf1-1 mutant lines show an altered response to salt stress in Arabidopsis thaliana. (A,B) 3-day-old Col-0 WT, nac4-2, and szf1-1 lines were transferred to MS medium supplemented with 0, 100, or 150 mM of NaCl for five days. Primary root growth under NaCl treatment (A) and lateral root primordia density (B) were quantified. (C,D) Germination rates of Col-0 WT, nac4-1, and szf1-1 plants were determined on MS medium (C) and the same medium supplemented with 150 mM of NaCl (D). ANOVA and Bonferroni a posteriori tests were performed. *: p < 0.05. a, b, c, d represents statistically significant differences with p < 0.05. Error bars represent the standard error of the mean. Each experiment was performed in triplicates with at least 12 seedlings (A,B) or 100 seeds (C,D) per treatment.