The content of phenols and activity of polyphenol oxidase in the hametophyte of dominant mosses in forest ecosystems of the Ukrainian Roztochia

Abstract

Bryophytes are indicators of the state of forest ecosystems. Dominant species of forest mosses are sensitive to the influence of abiotic factors and demonstrate adaptive reactions different from vascular plants, which are decisive for the prediction of changes in the natural environment. We have analyzed the changes in the content of water-soluble phenols and the activity of polyphenol oxidase n the hametophyte of dominant epigean forest mosses depending on changes in the intensity of insolation, the water and temperature regime of soils and air in experimental localities of forest ecosystems of the Ukrainian Roztochia. The highest content of water-soluble phenolic compounds was found in the resistant mosses Polytrichum formosum and Atrichum undulatum on the territory of protected beech forest under conditions of low light intensity and sufficient humidity of local vegetation. The maximum indicators of the content of phenolic compounds were found in A. undulatum (199.5±9.8 μg/g of dry matter mass), and the lowest – in Plagiomnium affine (54.7±2.6 μg/g of dry matter mass) that is sensitive to changes in the ecological conditions of local vegetation in all studied areas. A significant decrease in the content of phenolic compounds in areas of disturbed ecosystems may indicate the active participation of phenols in the adaptation of mosses to the effects of high light intensity, elevated temperatures and moisture deficit. The highest indicators of polyphenol oxidase activity were determined in P. affine (120.4±6.1 relative units/g of dry matter mass*s) and P. formosum (41.8±2.1 relative units/g of dry matter mass*s) from local vegetation under unfavorable conditions on the territory of stationary recreation. A direct correlation between the content of phenolic compounds and the activity of polyphenol oxidase was not established. The higher activity of this enzyme under conditions of high light intensity than in shaded local plants may indicate a relationship between polyphenol oxidase and photosynthesis. An increase in the activity of polyphenol oxidase contributes to the significant formation of quinones, which, accumulating in cell walls, reduce the processes of lipid peroxidation, regulate their permeability and ensure better moisture storage in the moss turfs.