Metal homeostasis and detoxification-Toxicity and detoxification of cadmium in the aquatic macrophyte Ceratophyllum demersum

摘要

The heavy metal cadmium (Cd) is an important pollutant and poisonous to many organisms. We studied the effects of Cd on C. demersum under environmentally relevant conditions. High, moderate and low concentrations of Cd had different effects. Lethally toxic concentrations (100–200 nM) led to growth stop and the plants' ability to perform photosynthesis (measured as F_v/F_m) decreased more than twofold, consistent with decreased pigment content. Moderately toxic concentrations (10–50 nM) led to reduced growth, slightly reduced pigment content, but hardly affected photosynthesis (measured as O_2 exchange and as F_v/F_m). Lower concentrations (0.2–5 nM) even had beneficial effects, like enhanced growth rate.