Fig. 3From: Characterisation of early responses in lead accumulation and localization of Salix babylonica L. rootsAnalysis of PI fluorescence density detected by Image J at longitudinal sections of roots exposed to 1, 10, 50, or 100 μmol/L Pb for 3, 6, 12, and 24 h. Vertical bars denote the SE. Different letters indicate significant differences (p < 0.05)Back to article page