Air pollution is one of the important problems of large cities. In connection with this, comprehensive study of the mechanisms of the corresponding reactions of tree species, introduced in the process of landscaping, to various environmental factors is required. The aim of this study is to analyze the influence of urban technogenic environmental pollution on the anatomical characteristics of Quercus rubra Linnaeus, 1753 annual shoots. The object of research was 35-year-old plants of Q. rubra, which grew in a non-polluted site (conditionally clean zone), the Botanical Garden of DNU (plot 1) and in a polluted site (roadside planting) (plot 2) of Dnipro City. Industrial emissions of the city's western, northeastern and northwest industrial complexes also have an effect on plants, depending on the wind direction. For anatomical research, the annual shoots were taken at the tips of the vegetation from the south-eastern side of the model trees at a height of 2 m and fixed in 70% alcohol. Cross sections were made at a distance of 1 cm from the beginning of growth. Phloroglucine was used to dye the cells. The influence of industrial and automobile emissions on the structural parameters of Q. rubra shoots was investigated. We established that the membrane thickened evenly in both control and experimental plants. Cork thickness of Q. rubra shoots, growing in the roadside plantation was higher than in plants of the Botanical Garden by 57.5%. Increasing its thickness in plants exposed to atmospheric air pollution has an adaptive value. Q. rubra shoots have a tabulate type of collenchyma, the tangent walls of whose cells thicken. The collenchyma cells of the control variant of shoots are larger. This tissue was thicker in Q. rubra shoots from the polluted site by 26.8% compared to those from the non-polluted zone. The parenchyma cells of the primary cortex were large and contained chloroplasts. The thickness of this histological element on the shoot circumference varied considerably both in the control and experimental variants, which is the result of its uneven formation. This is due to the fact that the shape of the shoot core resembles a pentagonal star, and the layers of phloem and xylem tissues repeat its shape. The thickness of each of them in the cross section of the shoots in various places varied little, while the parenchyma of the primary cortex above the ray cells was narrower, and between them was broader, as a result the thickness of the shoots was aligned in a circle. In areas where the parenchyma of the primary cortex was narrower, it was better developed in the shoots of experimental plants than the control ones, but where its layer was thicker, it was more developed in plants of the control variant. The diameter of the primary cortex in the shoots of the experimental variant in its narrower parts was 120.5% of the control, and in the broader -87.6%, which is due to unequal changes in the thickness of the primary cortex parenchyma, possibly with different rates of cell division. In the one-year Q. rubra shoots...

We have investigated the main parameters of water exchange in leaves of Quercus robur L. which grow on the south-facing slope of the Viyskoviy ravine in a variety of water supply conditions. We established that the greatest intensity of transpiration of leaves of Q. robur occurred in the forest vegetation conditions of SG2, the smallest in SG1–0. In all study periods the largest amplitude of daily fluctuations in intensity of transpiration occurred in leaves of plants along the talweg, at other test sites the limits were much lower. The highest rates of transpiration were in September, which is connected with the high temperatures and lower relative air humidity compared with the days of measurement in July and May. We established that at the beginning of the growing season there was no difference in the total amount of water in the leaves of the trees that grow on the middle and upper parts of the slope, but that it was greater in plants along the talweg. In the following months the difference between the water content in the leaves of trees along the talweg and upper third of the slope increased. The leaves of trees that grow in the poorest conditions of water supply were characterized by the highest water-holding capacity, which is coordinated with their containing the highest content of hydrophilic colloids. The values for water deficit in May and in July fell within the maximum fluctuations for the species studied, but in early September they exceeded the maximum value in the leaves of trees on the upper third of the slope.

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<p>The influence of growing of <em>Quercus rubra</em> L. trees in the groups and solitary on leaf indices and their anatomical structure in comparison with indigenous species <em>Quercus rоbur</em> L. under the same conditions was investigated. The bigger area of leaves and their green weight in plants of both species growing in groups is revealed. Both <em>Q. rubra</em> and <em>Q. rоbur</em> leaf cuticle thickness is increasing with solitary growth, while in <em>Q. rubra</em> also increasing the height of the cells of the adaxial epidermis; in <em>Q. rоbur</em>, such changes have not been established. Under conditions of solitary growth of trees, the density of stomata per unit area of the epidermis is greater in both <em>Q. robur</em> and <em>Q. rubra</em>, relative to data from these plants growing in the groups by 30.6% in the first and by 25.3% in the second species. In single trees, there are a decrease in their size. For solitary landing, the length of cells of the palisade mesophyll is greater in the leaves of both tree species, but their width is reduced. The width of the palisade tissue of leaves in <em>Q. rubra</em> is greater in single trees than in groups of plants, while <em>Q. robur</em> has the same pattern, but the difference between the variants is greater (25.89%). Both spongy parenchyma of leaves of Q. rubra growing solitary and growing in groups has not difference in size, but in Q. robur there is some thickening of it by 10.16%. Indicators of the relation of the size of the palisade parenchyma to the spongy parenchyma in both species on the two sites are almost identical. In single trees of both species due to the greater shortage of air and soil moisture, some anatomic-morphological parameters change in the direction of xeromorphism, which can be considered as adaptive.</p>

сравнение показателей водного обмена листьев дуба красного (Quercus rubra L.) и дуба обыкновенного (Quercus robur L.) в искусственном насаждении и на открытом пространстве. Установлено, что у отдельно растущих деревьев листья Q. robur характеризуются преимущественно бόльшей интенсивностью транспирации во все месяцы исследования, меньшей водоудерживающей способностью и бόльшим водным дефицитом, чем листья Q. rubra. В насаждении у большинства растений обоих видов испарение воды менее значительное, чем у отдельно растущих деревьев. Показатели водного дефицита листьев Q. robur в открытом пространстве превышают таковые у Q. rubra, а в насаждении, наоборот, они больше у Q. rubra. Для относительной тургоресцентности характерна противоположная закономерность. Полученные результаты можно объяснить более слабой конкурентоспособностью за влагу Q. rubra в насаждении. По показателям водного режима Q. rubra является достаточно устойчивым видом в условиях засушливого климата степи Украины и по ряду из них не уступает Q. robur, что свидетельствует о возможности широкого использования этого интродуцента в искусственных лесных насаждениях и в озеленении населенных пунктов в этой зоне. Ключевые слова: Q. rubra, Q. robur, водный режим, транспирация, водоудерживающая способность, водный дефицит, относительная тургоресцентность Для цитирования: Бессонова, В. П. Показатели водного обмена листьев дуба Quercus robur L. и Quercus rubra L. в различных условиях произрастания в северной подзоне степи Украины / В. П. Бессонова, А. П. Криворучко // Вес. Нац.