Cadmium toxicity and accumulation in southern naiad

The effects of 3 different levels of cadmium on the uptake and accumulation of this metal by pondweed, Najas quadulepensis, was studied. Exposed plants demonstrated reductions of chlorophyll, turgor, and stolon development while no such toxic effects were noted in the controls. In all exposure levels except one, an equilibrium developed between the levels of Cd in the water and in the tissues. This was based on the absence of significant additional accumulation after the 11th day of exposure. Toxic reactions and Cd accumulation by the plants increased as the exposure levels increased, which suggested that (a) Cd accumulation, similar to 1000 fold, was a direct function of the exposure level, and (b) the detoxifying mechanism was over-taxed at a more rapid rate at the higher levels resulting in an earlier impairment of physiological function.