A newly found cadmium accumulator-Taraxacum mongolicum

Identification of hyperaccumulator and accumulator is still key step of phytoextracting-contaminated soils by heavy metals. In a former published experiment, Taraxacum mongolicum showed basic characteristics of hyperaccumulators. In order to confirm if this plant was a Cd-hyperaccumulator, concentration gradient experiment and sample-analyzing experiments were designed and performed. The results showed that Cd enrichment factor and Cd transformation factor of T.mongolicum were all higher than 1 in concentration gradient experiment. The shoot biomasses did not reduced significantly (p < 0.05) compared with the control without Cd added under the conditions of lower than 25 mg kg(-1) Cd spiked into soil. However, Cd concentration in shoot of T.mongolicurn was not higher than 100 mg kg(-1) the minimum a Cd-hyperaccumulator should have under the conditions of any concentration level of Cd spiked. Thus, T mongolicum should be a Cd-accumulator. In the sample-analyzing experiments settled in a Pb-Zn mine area and Shenyang wastewater irrigation region, T. mongolicum also showed that Cd-accumulator characteristics. Based on these results, T mongolicum could be identified as a Cd-accumulator, which may have important implication in plant physiology and gene engineering. (C) 2008 Elsevier B.V. All rights reserved.