S. grandiflora callus grown in the presence of different concentrations of Pb (0, 50, 100 and 150 ppm). These cultures tolerated Pb up to a concentra-tion of 150 ppm. Callus accumulated Pb determined by Atomic absorption spectrophotometer. Pb accumulation reached 29.65 ppm (dry weight) at a Pb treatment of 150 ppm.