Assessment of DNA damages stemming from toxic chemicals is an important issue in terms of genotoxicology. In this study, maize (Zea mays L.) seedlings were used for screening the genotoxic effects of cobalt (Co) and nickel (Ni) treatments at various concentrations (5 mM, 10 mM, 20 mM and 40 mM). For this purpose, randomly amplified polymorphic DNA (RAPD) technique was applied to genomic DNA extracted from metal-exposed and unexposed plant materials. Besides, changes in total protein contents were screened by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) analysis. For RAPD analysis, 16 RAPD primers were found to produce unique polymorphic band profiles on different concentrations of Co-/Ni-treated maize seedlings. Increased polymorphism resulting from the appearance of new bands or disappearance of normal bands was observed with increasing concentration of Co and Ni treatments. Genomic template stability, a qualitative measurement of changes in RAPD patterns of genomic DNA, decreased with increasing metal concentration. In SDS-PAGE analysis, it was observed that the total soluble protein content decreased by Co treatment, while it increased by Ni treatment. The results obtained from this study revealed that RAPD profiles and total soluble protein levels can be applied to detect genotoxicity, and these analyses can offer useful biomarker assays for the evaluation of genotoxic effects on Co- and Ni-polluted plants.

This study was conducted to evaluate the influence of cadmium (Cd) (0, 100, 150 and 200 mg kg-1) and lead (Pb) (0, 1000, 1500 and 2000 mg kg-1) on morphological, physiological and biochemical responses of rocket (Eruca sativa L.) in greenhouse conditions. Plant growth, some physiological (membrane permeability, relative water content, stomal conductance, etc.) and biochemical (antioxidant enzyme activity, proline and sucrose content) parameters of rocket plants were altered with Cd and Pb levels. The Cd and Pb content in rocket increased with elevated concentration. Both Cd and Pb stress conditions negatively affected plant growth, photosynthetic activity and chlorophyll content. The negative effect of heavy metals elevated with increased doses of Cd and Pb. The treatment of Cd and Pb significantly elevated antioxidant enzyme activities. Furthermore, the heavy metal stressed plants had more malondialdehyde (MDA), hydrogen peroxide (H2O2), proline and sucrose as compared to control plants. This study indicated that rocket plants developed defense mechanisms by regulating enzyme activity and osmolyte accumulation against heavy metal stress.