Biochemical-physiological responses of Reseda lutea, Epilobium dodonaei, and Gentianella ciliata to stress in an open pit of an abandoned iron mine

Abstract The photosynthetic pigments, antioxidant properties, and heavy metal content in Reseda lutea, Epilobium dodonaei, and Gentianella ciliata were examined in response to stress in the open pit of an abandoned iron mine. The soils were shallow, alkaline, and severely deficient in phosphorus, potassium, and humus. Heavy metal concentrations in the rhizospheres followed the order Fe > Mn > Pb > Zn > Cu > Ni > Cr > Cd for all three species, with Cu, Zn, and Pb exceeding the limits established by Bosnian legislation. The results indicated that the bioelements Cu, Zn, and Mn were within permissible limits set by FAO/WHO. Epilobium dodonaei acted as a Cd accumulator. The highest content of photosynthetic pigments was observed in this species. Positive correlations were detected between Cr and total phenolics, Cr and total flavonoids in E. dodonaei, Pb and total phenolic acids in G. ciliata. Negative correlations were noted between Zn and total phenolic acids in R. lutea, and Fe and total phenolics in E. dodonaei. Increased total proline and DPPH concentrations were associated with heightened Fe levels in E. dodonaei. These findings suggest that the species analyzed employ distinct defense mechanisms, enabling them to effectively adapt to stress. NOVELTY STATEMENT Three abundant plant species with different responses to the stress conditions of the abandoned iron mine were the focus. The analyzed biochemical-physiological parameters for all studied species on alkaline soils and, in general, for Gentianella ciliata are presented for the first time.