Cadmium (Cd) is non-essential and toxic. Sulfur (S) addition to contaminated soils reduces Cd toxicity in rice and corn. I aimed to determine the underlying mechanisms by which S reduces Cd toxicity in hydroponically- and soil-grown soybean. In the presence of Cd, plant biomass was reduced by ~20%, Cd accumulated up to 45 μg/g in roots and 15 μg/g shoots, and concentrations of Cd chelators increased by more than 10-fold. Addition of S to Cd- treated plants had no effect on plant biomass, concentrations of Cd in roots and shoots, or vacuolar Cd sequestration in the root cortex. While additional S visibly altered Cd localization in the roots, it had no effect on altering Cd concentration in root plaque. Additional S in the presence of Cd resulted in a 0- to 1.5-fold increase in Cd chelator concentrations; however, addition of S to alleviate Cd toxicity has no benefit in soybean
