Toxicity and DNA damage in tobacco and potato plants growing on soil polluted with heavy metals.

Heterezygous tobacco (Nicotiana tabacum var. xanthi) and potato (Solanum tuberosum var. Korela) plants were cultivated on soil from the site Strimice which is highly polluted with heavy metals and on nonpolluted soil from the recreational site Jezerí, both in North Bohemia, Czech Republic.

Cadmium induces DNA damage in tobacco roots, but no DNA damage, somatic mutations or homologous recombination in tobacco leaves.

The heavy metal cadmium (Cd(2+)) applied on tobacco roots in the form of cadmium chloride, induced significantly higher levels of DNA damage as measured by the cellular Comet assay than did treatment of isolated root nuclei, analyzed by use of the acellular Comet assay. DNA damage induced by Cd(2+) in roots of a transgenic catalase-deficient tobacco line (CAT1AS) was higher than in wild-type tobacco (SR1) roots. In contrast to treatment with the positive control ethyl methanesulphonate, Cd(2+) induced no significant DNA damage in leaf nuclei, and neither somatic mutations, nor homologous recombination as measured by the GUS genereactivation assay, were observed in leaves.