Cadmium and Copper Uptake and Translocation in Five Willow (Salix L.) Species

ABSTRACT

The efficacy for phytoremediation of five willow species was tested by experimental copper and cadmium uptake in a greenhouse hydroponic system. Five treatments included two concentrations (5 and 25 μM for each metal) and a control. Metal concentrations in solution as well as solution uptake were monitored. Metal resistance was assessed through effects on the dry weight of roots and shoots. The willow species tested were generally resistant of increased Cu and Cd content. Metal accumulation was found in all plant organs of all species. Growth and transpiration were not decreased by 5 μM of copper and 25 μM of cadmium in the solution for most species. 25 μM copper caused injury and reduced the dry weight for all species after 21 d. Salix nigra was highly resistant of both Cu and Cd and accumulated more metals than other species. Future field study should be conducted to confirm the findings and feasibility of the phytoremediation technology using those species.

Keywords:

• Salix
• willow
• heavy metals (cadmium and copper)
• metal resistance
• hydroponic culture.

ACKNOWLEDGEMENTS

The authors gratefully acknowledge the assistance Dr. John Olesik and the staff of the Microscoping and Chemical Analysis Research Center (MARC) of the Ohio State University for helping with the analyses of metals in plant tissues. Research support was provided in part by funds appropriated to the Ohio Agricultural Research and Development Center, The Ohio State University.