ENVIRONMENTAL ASPECTS OF THE INFLUENCE OF POLYCHLORINATED BIPHENYLS ON THE ENZYME ACTIVITY OF BIDENS TRIPARTITA L.

Osinkina Tatyana Vladimirovna

This article presents the results of an experimental study investigating the effects of polychlorinated biphenyls on the activity dynamics of certain oxidases in Bidens tripartita L. Superoxide dismutase and peroxidase activity were determined spectrophotometrically, and catalase activity was measured by permanganatometry. Polychlorinated biphenyls were used in the formulation of "Sovtol," a mixture of 4-, 5-, and 6-chloro-substituted biphenyl derivatives. The activity of antioxidant enzymes, as factors of environmental adaptation, was determined during all stages of Bidens tripartita development: seedling, vegetation, and flowering. It was shown that, under the influence of polychlorinated biphenyls at a concentration of 0.001 mg/L, superoxide dismutase activity was highest at the seedling stage, exceeding the control by 3.6 times, and at the vegetation and flowering stages by 5.4 and 4.0 times, respectively. Primary exposure to toxicants at a concentration of 0.0005 mg/L had no significant effect on superoxide dismutase activity. The increase in superoxide dismutase activity at the seedling stage is possibly due to either the stabilizing effect of toxicants on the enzyme during initial exposure or to increased activity and production of enzyme forms more resistant to polychlorinated biphenyls, specifically during this period of plant development. Catalase and peroxidase activities exhibited similar dynamics at the seedling, vegetation, and flowering stages, showing a sharp increase following primary exposure to toxicants in a model experiment, demonstrating the phenomenon of a paradoxical dose-response relationship (hormesis). Bidens tripartita is a pharmacopoeial plant species. It is a source of biologically active compounds with a wide variety of chemical and pharmacological activities. A model experiment showed that the plant apparently forms ecological adaptations of biochemical parameters (antioxidant enzymes) to the action of polychlorinated biphenyls.

Keywords:ecological adaptations; bioindicators; toxicants; antioxidant enzymes; tripartite Bidens; polychlorinated biphenyls; superoxide dismutase; catalase; peroxidase; hormesis.