Сезонна динаміка антиоксидантних процесів у листках Acer negundo за дії полютантів
Seasonal dynamics of antioxidative processes in Acer negundo leaves under pollutant action

Summary/Abstract: Activity of superoxide dismutase (SOD, EC 1.15.1.1), catalase (САТ, EC 1.11.1.6), peroxidase (POD, EC 1.11.1.7), glutathione peroxidase (GPX, EC 1.11.1.9) and glutathione-S-transferase (GST, EС 2.5.1.18) were measured by spectrophotometrical method in Acer negundo leaves collected during May–August in DNU Botanical garden (control) and in Dnipropetrovsk polluted ecocenoses (plots 1, 2 and 3) in order to reveal the conformities of seasonal dynamics changes of antioxidative processes under pollutant action. The seasonal dynamics of SOD activity altered significantly under chronic pollutant action especially in leaves from plots contaminated by Lorries exhaust fumes and industrial emissions (r = 0.45, r = 0.08 and r = 0.25, accordingly, on plots 1, 2 and 3). The dynamics of CAT activity because of car exhaust fumes influence was similar to control (r = 0.92), whereas it changed more considerably under influence of two other types of contamination (r = 0.80). POD activity seasonal dynamics altered insignificantly in all polluted plots, and it may indicate the predomination of catalase pathway of hydrogen peroxide detoxification in Acer negundo leaves against the background of pollutant action. Furthermore, the increasing of correlative coefficients of seasonal dynamics of CAT and POD activity (from r = –0.18 on control to r = 0.28, r = 0.64 and r = 0.73, accordingly, on plots 1, 2 and 3) may indicate more coordinative functioning of catalase and peroxidase metabolic pathways as adaptive sign of trees from polluted urbocenoses. The seasonal dynamics of GPX activity in tree leaves sgarply varied from control subject to all contaminated plots (r = 0.04, r = –0.97 and r = –0.78), and it was followed by enhancing positive correlative links between dynamics of GPX and SOD activities (from r = –0.60 on control to r = 0.51, r = 0.70 and r = 0.93 on polluted plots). The dynamics of GST activity in A. negundo leaves did not change under pollutants action, instead of this correlative analysis revealed the intensification of negative links of GST dynamics with SOD (from r = 0.03 on control to r = –0.85, r =–0.98 and r =–0.93 on plots 1, 2 and 3) and GPX dynamics (from r = 0.25 on control to r = –0.88, r = –0.56 and r = –0.80 on plots 1, 2 and 3). The established conformities indicate the coordination of antioxidative processes in A. negundo leaves against the background of combined chronic pollutant action and may be considered as the index of A. negundo species metabolic resistance to anthropogenic pollution of urban cenoses.

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