Phytoremediation of Cd-contaminated Soils by Datura stramonium L

The contamination of soils with heavy metals is a grave environmental problem. Among the heavy metals, Cadmium (Cd) is regarded as one of the most toxic trace elements and environmental pollutants. The aim of this research is investigation of phytoremediation ability of Datura stramonium L. for Cadmium (Cd) and also, the enhancing effect of EDTA (ethylenediamine tetraacetic acid), indole-3-acetic acid (IAA) and kinetin (KN) on the uptake of Cd. Four levels of cadmium (0, 75, 150 and 225 mg kg-1) and different enhancers including EDTA (0, 3, 6, 12 mmol kg-1), IAA, and kinetin (0, 1, 10, 100 mg L-1) were used as the experimental groups. Analysis of Cd in soil and plant materials was carried out using an atomic absorption spectrophotometer. The bioconcentration factor, translocation factor, protein content and enzymatic activity were also measured. The results showed that D. stramonium was a Cd accumulator plant with the TF of 1.12. Accumulation ability was increased with the application of the chelating agent and plant hormones; EDTA was found to be more effective in the enhancement of phytoremediation than others. Application of EDTA and hormones reduced the negative effects of Cd by means of increasing the total protein content and peroxidase activity. The total protein content in the leaves of D. stramonium, which had been treated with Cd/EDTA, Cd/KN and Cd/IAA, was increased 2.24, 3.59 and 3.41 times more than that in the Cd treated group, respectively. The highest peroxidase (POX) activity was determined in the group treated by 150-Cd +100-IAA (0.060 unit/mg protein). It could be concluded that D. stramonium is a Cd-accumultor plant with phytoremediation potency. This study also demonstrated that EDTA and plant hormones (IAA and Kinetin) could be regarded as good strategies for increasing the phytoremediation ability of D. stramonium.