Characteristics of Soil Lead Tolerance, Accumulation and Distribution in Salix babylonica Linn. and Salix jiangsuensis J172

Abstract

Patience plants provide a good way for phytoremediation of environmental pollution. In this paper,two willow species,Salix babylonica Linn. and S. jiangsuensis J172 were selected to test the lead tolerance,lead accumulation and distribution in plants through pot experiments with different soil Pb concentrations. The results showed that a significantly negative correlation relationship existed between S. babylonica and soil available lead,the biomass of root for Salix insignificantly decreased under low concentrations of Pb2 +at a variation of0- 1 200 mg· kg- 1and 0- 800 mg · kg- 1for S. babylonica Linn. and S. jiangsuensis J172,respectively,which suggested that S. babylonica Linn. had a better tolerance than S. jiangsuensis J172 under Pb2 +stress. The root length,root surface area,root volume and root diameter of both willow species decreased with the increase of soil Pb2 +concentration. At Pb2 +concentration of 1 600 mg·kg- 1,the root length,root surface area,root volume and root diameter of S. babylonica Linn. and S. jiangsuensis J172 decreased by 50. 40%,45. 15%,44. 44%,9. 10%,and 45. 00%,45. 88%,47. 02%,37. 14%,respectively,as compared with the control.Both willow species accumulated more lead in roots than that in stems and leaves,the order of lead accumulation in different organs of two kinds of willows are root stem leaf. At Pb2 +concentration of 800 mg·kg- 1,the tolerance indices of S. babylonica Linn. and S. jiangsuensis J172 were 91. 15% and 84. 26%,the uptake of lead from the soil in them reached 140. 20 and 149. 49 mg,respectively. These results indicated that these two willow species has greater potential for restoration of medium soil lead contamination.