Responses of Se sbaniaro strata and S. cannabina to Pb, Zn, Cu and Cd toxicities were as sessed by a seed-suspending seedbed (SSS) approach. The results showed that the SSS approach was suitable for te sting the tolerance of a plant to the stress of toxic metals. The endpoints include seed germination success, straightened radicle and hypocotyl of the seedlings from the seeds. The mea surements could be done ea sily and accurately. It wa s found that the elongation of radicle was the most sensitive indicator to the stre s s of heavy metals among the endpoints. When expo sure to lower or medium concentrations of Pb, Zn, and Cd, the development of the lateral roots were favorable. Species of S. ro strata wa s more tolerant than S. cannabina to the heavy metals, e specially to Zn and Cd. The ED50 of Pb, Zn, Cu and Cd were 32.90, 5.32, 4.40 and 12.00μgPml for S. ro strata, re spectively, and they were 30.11, 2.87, 4.05 and 4.94μgPml re spectively for S. cannabina.