HYPERACCUMULATION OF CADMIUM IN MAIZE PLANT (Zea Mays)

Maize plant responses, in terms of growth and metal uptake, to different concentrations of cadmium ions (4, 20 mu M) were analyzed in a hydroponic culture, for 2 weeks. For a 4 mu M cadmium-contaminated environment, the maize plant presents the highest bioaccumulation level after 192 h, with a recovery degree of 52%, meanwhile, at a 20 mu M concentration, the highest bioaccumulation was registered after 366 h, with a corresponding recovery degree after 288 h (10.56%). The translocation factor presented higher values for 20 mu M induced contamination than for 4 mu M, which means that increasing metal concentration in the medium increased the concentration in the upper parts of the plant. Anatomical sections of a maize plant (in a 4 and 20 mu M cadmium-contaminated environment) were observed to evidence the changes in plant morphological structure. The efficiency of phytoextraction is related to the metal concentration in the environment and to the plant's ability to grow on polluted soil sites, concomitantly with a high biomass yield.