Uranium and cadmium provoke different oxidative stress responses in Lemna minor L.

摘要: Common duckweed (Lemna minor L.) is ideally suited to test the impact of metals on freshwater vascular plants. Literature cadmium (Cd) and uranium (U) oxidative responses in L. minor are sparse or, for U, non-existent. It was hypothesised that both impose concentration-dependent stress growth retardation L. minor. Using a standardised 7-day inhibition test, adverse these confirmed, with EC50 values Cd U 24.1 ± 2.8 29.5 ± 1.9 μm, respectively, EC10 1.5 ± 0.2 6.5 ± 0.9 μm, respectively. The metal-induced response compared through assessing activity different antioxidative enzymes [catalase, glutathione reductase, superoxide dismutase (SOD), ascorbate peroxidase (APOD), guaiacol (GPOD) syringaldizyne (SPOD)]. Significant changes almost all indicated their importance counteracting U- Cd-imposed burden. However, some striking differences were also observed. For APODs SODs, biphasic but opposite at low concentrations found. In addition, (0.5–20 μm) strongly enhanced plant GPOD activity, whereas inhibited it. Finally, contrast Cd, up 10 μm increased level chlorophyll b carotenoids. conclusion, although induce similar arrest L. minor, U-induced responses, studied here first time, differ greatly from those Cd.