engleski

Integrative approach gives new insights into combined Cd/Cu exposure in tobacco

Heavy metals are generally known to induce oxidative stress, but are rarely strategically studied in an embracive manner, taking into account interplay between their various effects. Furthermore, although metals in the environment are present in mixtures and interact with each other, their combined effects to organisms have been much less studied in comparison to individual effects. Here we present a complete comprehensive study of Cd/Cu oxidative stress interactions in Nicotiana tabacum seedlings and adult plants. Plants were treated with Cd (10 µM and 15 µM), Cu (2.5 µM and 5 µM) and their combinations ; seedlings during one month-period and adult plants during the period of 7 days. Metal accumulation measurements showed that Cu stimulates Cd uptake in roots, while reducing Cd translocation to shoots. We employ the power of extensive principal component analysis (PCA) to decipher differences and similarities in antioxidative response to these two metals. PCA analysis showed that although indicators of oxidative damage to biomolecules highly correlate across tissues, seedlings show greater sensitivity in terms of DNA, while adult plants in terms of protein and lipid oxidation. Majority of toxic effects were caused by Cd alone, with addition of Cu often resulting in damage alleviation. However, mixture of high concentrations of both Cd and Cu induced most adverse effects. In conclusion, our results indicate that copper in lower concentration has antagonistic effect to cadmium toxicity, while in higher concentration these metals interact synergistically in tobacco.

Nicotiana tabacum ; metal mixture ; cadmium ; copper ; biomarkers ; oxidative stress

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