Phenolic plant defense system under conditions of environment pollution by heavy metals in Tyumen

Abstract

The mechanisms of plant persistence to the heavy metals effect, including the change in flavonoids and phenolic antioxidants status, is of great importance. The aim of this research is to investigate the impact of heavy metal (Cu, Fe, Mn, Pb, and Cd) accumulation in herbs of various species in Tyumen on the content of phenols and flavonoids. The material has been collected near various industrial facilities of Tyumen: metallurgical, engine-building, oil refinery, and battery. The studied sites also include the highway area. The following species of plants have been sampled: coltsfoot (Tussilago farfara), meadow grass (Poa pratensis), red clover (Trifolium rubens), chamomile (Matricaria chamomilla), and wild vetch (Vicia cracca). The analysis of heavy metal concentrations in plants has been performed by atomic absorption spectrophotometry. The concentration of phenols in plants has been determined by titration, while the analysis for flavonoids has been carried out photometrically. The species-specific accumulation of heavy metals has been observed. It has been found that the highest content of Mn is accumulated by coltsfoot. In general, the accumulation of heavy metals decreases in the following order: Fe > Cu > Mn > Pb > Cd. The highest concentrations of heavy metals were registered near the metallurgical plant. The change in the status of phenols and flavonoids has also turned out to be species-specific. In the cells of coltsfoot, the content of phenols and flavonoids is higher than in the control plants almost in all test groups. At the same time, the concentration of antioxidants in red clover decreases. The high correlation coefficients have been registered for the Cu, Fe, and Mn concentration and the content of phenols and flavonoids, which proves the impact of heavy metals on the antioxidant defense system of plants under conditions of the urban environment.

Keywords

• heavy metals
• phenols
• flavonoids
• antioxidants
• plants
• urban environment