Cadmium and Nickel Adsorption and Uptake in Cattail as Affected by Iron and Manganese Plaque on the Root Surface

Abstract

The effects of iron (Fe) and manganese (Mn) plaque on the adsorption and uptake of cadmium (Cd) and nickel (Ni) in cattail (Typha latifolia L.) were investigated in nutrient solution cultures under laboratory conditions. Seedlings with and without Fe or Mn plaque on the roots (induced with 15 µg mL^− 1 Fe or Mn) were exposed to 0.2 and 0.8 µg mL^− 1 Cd, or 0.12 and 0.36 µg mL^− 1 Ni solutions for 22 days, respectively. The results showed that the amounts of Cd and Ni adsorbed on root surface with and without Fe or Mn plaque increased with increasing additions of Cd and Ni in the solutions. Typha latifolia with Mn plaque adsorbed more Cd and Ni, and with Fe plaque adsorbed more Cd on its roots, especially at higher Cd (0.8 µg mL^− 1) or Ni (36 µg mL^− 1) treatment solutions. The presence of Fe plaque can inhibit Cd (but not Ni), while Mn plaque inhibit Ni (but not Cd) uptake and translocation from roots to shoots at higher Cd or Ni solutions. The data here suggest that the formation of Fe or Mn plaque on roots can increase adsorption of certain metals depending on various factors such as type of metals and plaque, and metal concentration in solution.

Acknowledgments

The authors thank Professor A.D. Bradshaw, School of Biological Sciences, University of Liverpool, for his invaluable comments. Financial support from Research Grant Council of the University Grants Committee of Hong Kong, and Faculty Research Grant, Hong Kong Baptist University is gratefully acknowledged.