Heavy metal accumulation and changes in phenylpropanoid metabolism induced by mining activities in leaves of Pinus nigra and Pinus eldarica

Plants can absorb pollutants produced through industrial activities. In this research, biochemistry and lignin biosynthesis processes are studied in Pinus nigra and P. eldarica trees, that were exposed to pollutants from Sarcheshmeh copper complex and from the Kentuiyeh ascontrol area (both Iran). Needles were collected in areas adjacent to mining factory, where heavy metals (Cu, Zn, Cd and Pb) are accumulated in higher concentrations than in plants from control areas. Comparison of the two studied pine species reveals that P. eldarica needles amass heavy metals 27% more than P. nigra. There was a higher content of total phenolic compounds and flavonoids in needles growing in close vicinities of the mining activity. Lignin content was similar in both species of pine and remained unchanged regardless of the pollution level. Higher activities of enzymes in phenylpropanoid pathway in needles from polluted areas were measured for both pine species. Findings of this study suggest involvement of general phenylpropanoid pathway in heavy metal resistance of pine trees. It seems that P. eldarica can accumulate more heavy metals in its needles and it has greater resistance to pollutants.