Fig. 5

Effect of salinity and alkalinity stress on Fe concentration of lettuce leaves. Values are means of three replicates. Bars with different letters show significant differences at P ≤ 0.05 (Duncan test). Control (no stress), salinity (10 mM NaCl) and alkalinity (10 mM NaHCO3). Vertical bars indicate ± standard error of the mean (n = 3 independent replicates).