| Metals and polycyclic aromatic hydrocarbons (PAHs) are two prevalent classes of persistent co-contaminants. 1,2-dihydroxyanthraquinone (1,2-dhATQ) a derivative of the PAH anthracence was found to inhibit photosynthesis in Duckweed (Lemna gibba), however, other impacts of this contaminant are unknown.;The effects of cadmium and 1,2-dhATQ on L. gibba were determined by growth analysis, the production of reactive oxygen species, photosynthesis and gene expression analysis. 1,2-dhATQ was more toxic to plants at lower concentrations than cadmium. Mixtures of cadmium and 1,2-dhATQ resulted in additive and synergistic impacts in some cases. Cadmium produced ROS whereas 1,2-dhATQ alone did not. In the mixtures 1,2-dhATQ reduced the level of ROS observed with cadmium alone at 4 d, however by 8 d the levels observed were equal to or higher than those levels observed for cadmium alone. Cadmium had a minimal impact on photosynthesis whereas there was a more noticeable effect with 1,2-dhATQ. Again, mixtures resulted in more damage to photosynthesis than the individual chemicals alone. (Abstract shortened by UMI.)... |
