Comparative analysis of anatomical structure of wood plant leaf under exposure to volatile organic compounds
Authors: Tyulkova E. G. 
Published: December 2020

Industrial enterprises of thermal power engineering, fuel, chemical and petrochemical industry, mechanical engineering, non-ferrous metallurgy are sources of volatile organic compounds, the emissions of which can now reach a significant amount due to changes in technological processes. Studying the effect of volatile organic compounds on changes in anatomical parameters of a plant sheet is a little-studied aspect compared to exposure to oxides of nitrogen, carbon, sulfur, ammonia, heavy metals. The aim of the work was therefore to study the anatomical features of the tree leaf as adaptive features under the influence of emissions from industrial plants containing selected volatile organic compounds. Time preparations of the cross section of the leaf were used for anatomical studies. The thickness of the epidermis, the mesophyll, the number of upper and lower epideric cells, the number of wellheads and their width, the size of the conductive beam, the palisadity coefficient (the ratio of the thickness of the columnar mesophyll to the sum of the thickness of the columnar and spongy mesophyll) and the oral index (the ratio of the number of wellheads to the total number of epidermal cells). Impressions of the upper and lower epidermis were made with colorless varnish. As objects for studying the features of the anatomy of the leaf were chosen the leaves of a number of species of wood plants, which are among the most common near the industrial enterprises of the city of Gomel: drooping birch Betula pendula Roth., maple holly Acer platanoides L. Leaf samples were taken in the zone of influence of emissions of industrial enterprises containing xylenes and butylacetate (JSC «Gomel plant leaves and normals»), as well as benz(a)pyrene (heat and power plant). As a result of the studies, the cells of the columnar mesophyll in the birch leaves were found to have the greatest sensitivity to organic toxicants (xylenes and butylacetate) at the end of the vegetation compared to the maple holly leaves and the parameters of the spongy mesophyll. Drooping birch was characterized as the species in which sclerenchyma in the region of the conducting bundle under technogenic conditions was the thinnest, especially at the beginning of the growing period. Also in birch, when growing around industrial plants, there was a decrease in the number of cells of the upper and lower epidermis compared to control in most variants, especially the upper epidermis in samples exposed to xylenes and butylacetate at the beginning of the growing period. Maple holly showed a more intense decrease in the number of oysters and the value of the oral index compared to control than birch. When exposed to the benz(a)pyrene of heat and power plant emissions, both wood plant species studied showed an increase in mesophyll palisadity coefficient during the most intensive sheet plate formation processes. The conducting bundles of the studied wood plants were characterized by a decrease in the largest diameter when growing under technogenic conditions, most intensively in may at the maple holly. In general, the study of anatomical features of leaf plates of wood plants when growing in the area of exposure to volatile organic compounds of industrial emissions is great interest in terms of understanding the adaptive mechanisms of plants to stress conditions. The seasonal dynamics of changes in anatomical parameters in the birch leaf was characterized by a decrease in their values in most cases in september compared to may in the territory of the industrial enterprises under consideration. In maple holly approximately in equal amounts there was both a decrease and an increase in anatomical parameters between may and september.