Original scientific paper
https://doi.org/10.2478/10004-1254-61-2010-2059
Effect of Copper on the Toxicity and Genotoxicity of Cadmium in Duckweed (Lemna minor L.)
Petra Cvjetko
; Department of Molecular Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
Sonja Tolić
; Department of Ecology, Institute of Public Health, Zagreb, Croatia
Sandra Šikić
; Department of Ecology, Institute of Public Health, Zagreb, Croatia
Biljana Balen
; Department of Molecular Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
Mirta Tkalec
; Department of Botany, Faculty of Science, University of Zagreb, Zagreb, Croatia
Željka Vidaković-Cifrek
; Department of Botany, Faculty of Science, University of Zagreb, Zagreb, Croatia
Abstract
We investigated interactions between copper (in the concentrations of 2.5 μmol L-1 and 5 μmol L-1) and cadmium (5 μmol L-1) in common duckweed (Lemna minor L.) by exposing it to either metal or to their combinations for four or seven days. Their uptake increased with time, but it was lower in plants treated with combinations of metals than in plants treated with either metal given alone. In separate treatments, either metal increased malondialdehyde (MDA) level and catalase and peroxidase activity. Both induced DNA damage, but copper did it only after 7 days of treatment. On day 4, the combination of cadmium and 5 μmol L-1 copper additionally increased MDA as well as catalase and peroxidase activity. In contrast, on day 7, MDA dropped in plants treated with combinations of metals, and especially with 2.5 μmol L-1 copper plus cadmium. In these plants, catalase activity was higher than in copper treated plants. Peroxidase activity increased after treatment with cadmium and 2.5 μmol L-1 copper but decreased in plants treated with cadmium and 5 μmol L-1 copper. Compared to copper alone, combinations of metals enhanced DNA damage after 4 days of treatment but it dropped on day 7. In conclusion, either metal given alone was toxic/genotoxic and caused oxidative stress. On day 4 of combined treatment, the higher copper concentration was more toxic than either metal alone. In contrast, on day 7 of combined treatment, the lower copper concentration showed lower oxidative and DNA damage. These complex interactions can not be explained by simple antagonism and/or synergism. Further studies should go in that direction.
Keywords
aquatic plants; DNA damage; ecotoxicological testing; heavy metals; oxidative stress
Hrčak ID:
58440
URI
Publication date:
17.9.2010.
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