Effects of Cd exposure and sulfate limitation on sulfate translocation in Brassica juncea plants. Plants were exposed to different Cd concentrations for 48 h (A) or grown under different sulfate concentrations for 10 days (B). At the end of the experimental periods, shoots were separated from roots and the xylem sap exuded from the cut (root side) surface was collected to be analyzed for sulfate content. Bars and error bars are means and SE of three experiments run in triplicate (n = 9). Different letters indicate significant differences (P < 0.05).