The article examines the anatomical changes in leaves of Turkish hazel (Corylus colurna L.) as an adaptation indicator to varying degrees of urban-technogenic stress in the urbanized environment of the city of Uman. Four growth conditions of nut-bearing plants were studied: a roadside area with heavy traffic, the protected zone of Sofiyivka Park, the administrative zone of the park, and the internal part of the park. Quantitative parameters of the respiratory apparatus in all experimental variants were obtained by studying epidermal imprints, while the thickness of the epidermis, mesophyll, and cuticle was measured using microscopic sections. Leaf morphometry included assessments of length, width, petiole length, and leaf blade area. Comparative analysis of anatomical parameters has shown that the leaves of Turkish hazel growing along the roads with heavy traffic demonstrated a number of distinct adaptive changes. First of all, they have an increased number of stomata, while at the same time their size decreases, which allows for more precise regulation of transpiration under conditions of increased dust and heat stress. The mesophyll in such leaves thickens evenly in both layers: the palisade parenchyma expands the photosynthetic surface, while the lacunose parenchyma increases the capacity of intercellular spaces for storing water and gases. This allows the maintaining of high photosynthetic productivity even under moisture deficit. At the same time, the upper and lower epidermal layers are compacted, forming a reliable barrier against mechanical and chemical stress. However, the cuticle layer is reduced due to the destructive effects of gas emissions. Despite all these changes, the external shape and overall dimensions of the leaf remain almost unchanged, indicating their morphological stability even under urban stress conditions. The data obtained confirm that complex changes in mesophyll cells, in particular thickening of the parenchyma and epidermis with a simultaneous reduction in the cuticle, have been established in the experimental samples of Corylus colurna L. which significantly contributes to the preservation of effective gas exchange, photosynthetic potential, and water retention capacity of leaves in an urban environment. The results indicate the feasibility of using Turkish hazel in the landscaping of urban areas in the RightBank Forest-Steppe of Ukraine to support sustainable plantings against urban stress factors.

Key words: Corylus colurna L., respiratory density, parenchyma, cuticle, epidermis, urban technogenic stress, xeromorphic adaptations.