土培条件下东南景天对镉的耐性和富集特性的研究

[目的]探讨土培条件下东南景天矿山与非矿山生态型植物对Cd耐性和富集能力的差异。[方法]采用土培盆栽的方法,以向水稻土中加入不同量的镉作为处理,研究东南景天两种生态型植物在不同镉含量土壤中的生长反应以及体内镉含量与积累量变化。[结果]两种生态型植物对土壤中不同含量Cd的生长反应不同,矿山生态型对土壤Cd的耐受阈值为300 mg/kg,非矿山生态型为50 mg/kg。矿山生态型地上部最大Cd含量为893 mg/kg,根部最大Cd含量为344 mg/kg;而非矿山生态型地上部和根部最大Cd含量分别为124和212 mg/kg。矿山生态型地上部Cd含量大于根部Cd含量,而非矿山生态型根部Cd含量大于地上部。矿山生态型地上部Cd积累量最大值为151.67μg/株;而非矿山生态型为11.99μg/株。两种生态型植物相比较,在相同Cd处理水平下,矿山生态型地上部Cd含量和Cd积累量均显著高于非矿山生态型。[结论]矿山生态型东南景天对土壤Cd的耐受和富集能力显著大于非矿山生态型。从植物对土壤镉的耐性、地上部与根部Cd含量及其比值来看,矿山生态型东南景天是一种Cd超积累植物。

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.