COPPER-INDUCED GENOTOXIC EFFECTS IN ROOT MERISTEMS OF TRITICUM AESTIVUM L. CV. BETI

Copper is one the most abundant heavy metals in agricultural soils and its excess in soil comes from the largely use of this heavy metal in industry and agriculture (as fungicide). Mitotic index, rate and categories of ana-telophase chromosome aberrations, as well as the frequency and types of metaphase disturbances were scored in root tip meristems of Triticum aestivum L. cv. Beti after seed exposure to copper, provided as copper acetate and copper citrate, at four concentrations (10, 25, 50, and 100 mu M) containing 0.64, 1.59, 3.18, 6.35 mu g Cu2+, and 1.91, 4.77, 9.53, 19.06 mu g ml(-1) Cu2+, respectively. Except the mitostimulant effect of 25 mu M concentration, all the other concentrations of copper acetate and copper citrate showed mitodepressive action. The copper genotoxicity is expressed in the increased level (1.5 - 5-fold higher than in control) of the rate of chromosome aberrations in mitotic ana-telophases of copper-treated variants. Chromosome bridges, laggards and complex aberrations are the most numerous, although multipolarity, fragments and micronuclei are present, but with lower frequency and not in all copper-treated variants. Concerning the rate of metaphase disturbances, copper acetate augmented 2 3 times the rate of abnormalities in all variants, whereas only variant treated with 25 mu M copper citrate exceeded the control in a substantial manner. Metaphases with chromosomes expulsed from equatorial plate are numerically preponderant, followed by C-metaphases. These observations constitute a signal about the risks of the widespread and increasing presence of some heavy metals into environment. The results reported here could be considered in a future evaluation of copper effects on other organisms, even on human health, due to large use of copper compounds, inclusively as fungicides.