Improving Plant-Based Genotoxicity Bioassay for Trace Metal-Contaminated Water: Insights from Myriophyllum Aquaticum (Vell.) Verdc. and Cd.

Abstract

In this work, we evaluated whether the species Myriophyllum aquaticum (Vell.) Verdc. can be a promising material for devising reliable ecotoxicological tests for Cd contaminated waters. Plants of M. aquaticum were exposed to Cd, using different concentrations and exposure times, in order to address as many possible effects as possible of its presence. Plant growth and Cd accumulation were monitored along the treatment period and Cd genotoxicity was assessed by analyzing Cd-induced changes in the AFLP fingerprinting profiles. Root and shoot growth was reduced already at the lowest Cd concentration used (1 mg L-1). Shoots showed a higher Cd sensitivity and a lower accumulation, thus being chosen as the more suitable organ for the genotoxic analysis. DNA variation was observed starting from 2.5 mg L-1, indicating that the metal-induced depression of plant growth at the lower concentration did not necessarily imply a genotoxic effect. Similar results were obtained in the time-dependent experiment, since Cd effect on DNA fingerprinting profile was observed after three days of exposure and without a significant growth decrease growth. Therefore, our results showed that M. aquaticum proved to be a suitable model system for the investigation of Cd genotoxicity through AFLP fingerprinting profile, whereas the more classic eco-toxicological tests based only on biometric parameters could underestimate the risk associated to undetected Cd genotoxicity.