Study on Tolerance and Enrichment Characteristics of Sedum alfredii Hance to Cd in Soil Culture

[Objective] To reveal the differences of tolerance and uptake characteristics of cadmium in soil between mined ecotype and non-mined plants of S.alfredii.[Method] Using pot culture,different amount of Cd were put into soil as treatment,to study the growth responses of two ecotypes plants of S.alfredii in soil with different Cd content and the change of Cd content and accumulation.[Result] The growth responses were different obviously between the two plants.The tolerance threshold of mined ecotype S.alfredii to Cd was 300 mg/kg,and the non-mined ecotype was 50 mg/kg.Maximum Cd concentrations reached 893 mg/kg in shoots and 344 mg/kg in roots of the mined ecotype plant respectively;while the maximum Cd concentration in shoots was 124 mg/kg,the root was 212 mg/kg for the non-mined ecotype plant.Cd concentration in shoots was higher than roots for the mined ecotype,whereas Cd concentration was always lower in shoots than in roots for the non-mined ecotype.The Cd accumulation in shoots of the mined ecotype reached the maximum of 151.67 μg/plant,while the non-mined ecotype reached 11.99 μg/plant.Compare the two ecotypes of S.alfredii,concentration and accumulation of Cd in shoots of the mined ecotype was obviously higher than the non-mined ecotype in same content treatment of Cd in soil.[Conclusion] Cd tolerance and accumulation of the mined ecotype of S.alfredii is remarkably more than the non-mining ecotype.The mined ecotype of S.alfredii is a Cd hyperaccumulator.