Вплив забруднення повітря сполуками фтору, сірки та азоту на активність пероксидази та поліфенолоксидази у листках деревних і чагарникових рослин
Influence of air pollution by compounds of fluorine, sulphur and nitrogen on changes of peroxidase and polyphenol oxidase activity in the leaves of trees and bushes

Summary/Abstract: Productive activity of man results in contamination of the environment which causes substantial damage to ecosystems, upsetting their balance, species composition, etc. Within industrial areas, plants suffer significant harm. At the same time, plant organisms play an important role in optimization of the environment, performing sanitaryhygienic, landscaping and aesthetic functions. In this context, we investigated the influence of industrial contamination of air by fluorine, sulphur and nitrogen compounds on the activity of peroxidase and polyphenoloxidase in ten types of arboreal and shrub plants which differ in their resistance to air pollution. Our research was conducted on the basis of a full multivariate experiment with two levels of factors. Peroxidase activity was determined by a colorimetric method according to the duration of oxidization of benzidine. For determination of polyphenoloxidase activity we determined the duration of oxidization of p-phenilendiamin according to the change in optical density of the solution. Pollutants have a significant influence on activity of the investigated enzymes in the leaves of the plant species studied, which depends on the resistance of the plants to contamination, and also the composition and concentrations of pollutants. With resistant species (Ligustrum vulgare L., Quercus robur L., Lonicera tatarica L., Eleagnus angustifolia L., Philadelphus coronaria L.) peroxidase activity either did not change or rose by 11.2–64.1% compared to the control. depending on the composition of pollutants, their concentrations and the duration of their activity. Polyphenoloxidase activity in these plants did not significantly change in most variants of the experiment, although high concentrations of pollutants resulted in suppression of the activity of this enzyme by 26.1–37.6%. In species with variable tolerance which did not experience damage, peroxidase function did not change. Species sensitive to pollutants (Sorbus aucuparia L., Fraxinus lanceolata Borkh) were characterized by the significant decline in peroxidase and polyphenoloxidase activity, by 18.7–79.1% and 20.5–71.2% respectively, depending on the duration of action of the gases in all variants of the experiment. In species with variable tolerance (Aesculus hippocastanum L., Acer negundo L., Populus simonii Carriere) the reaction to the pollutants was ambiguous in nature and depended on the presence of damage. If the leaves of these plants did not show visible damage (necrosis), then activity of the enzymes did not change. When there was damage to leaf laminae this index decreased in relation to control by 17.3–60.1% for peroxidase and 24.7–57.3% for polyphenoloxidase. Significant negative linear correlation was found between activity of antioxidant enzymes and damage to leaves of the investigated plants: the coefficients of correlation were –0.385 between peroxidase activity and damage and –0.130 between polyphenoloxidase activity and damage. The character of changes in peroxidase and polyphenoloxidase activity show that these enzymes play a considerable role in the detoxication of pollutants and that there is a reduction in their influence on metabolic processes of plant organisms.

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