АNATOMICAL STRUCTURE OF THE LEAF BLADE OF PLANTS IN COENOPOPULATIONS OF <i>СORNUS MAS
The article presents the results of studying the anatomical features of the structure of the lamina of Cornus mas plants growing in different physiographic conditions of the Crimean peninsula. Five cenopopulations within the natural range of the species growing in different physiographic conditions of the Crimean peninsula were selected for study: on the southern and northern macroslope of the Main mountain range of the Crimean Mountains, in the foothill region, in its western and eastern parts. The study of plants was carried out according to standard methods of geobotanical research. The sample according to the experimental conditions within the same coenopopulation averaged from 15 to 27 individuals of Cornus mas. To study the anatomical features of the leaf structure of the cornel in each studied coenopopulation, 10-15 pieces were taken from plants with different parts of the crown, which were then fixed in an alcohol-water mixture at a ratio of 1: 3. Micropreparations were made by hand with a blade and stained with floroglucin and decolorized with hydrochloric acid. After appropriate treatment, immersed in a glycerol solution. Studies have shown a high degree of polymorphism in natural growing conditions, manifested in differences in the appearance of plants, their vital form (shrub or woody), morphological features of the leaf blade and the fruit. Anatomical analysis showed that the sheet is hypostomatic, bifacial, covered with epidermis and cuticle, the mesophyll is represented by a palisade and spongy tissue, the conducting system is an arcuate-curved closed collateral bundle with xylem and phloem. The mechanical fabric is formed by a corner bell. In each of the 5 studied cenopopulations, intraspecific variability was revealed for a number of different types of trichomes, differing in form and structural organization. In addition to the types of trichomes and their forms indicated in the scientific literature, we found a different form - a three-cell branched, double-vertex, T-shaped trichome, and the second type of trichome - a glandular. A clear differentiation of the mesophyll into the palisade and spongy parenchyma, the presence of stomata only on the underside of the leaf, a well-developed cuticle (up to 0.04 µm), the presence of many trichomes, makes it possible to classify the studied Cornus mas plants to the ecological group of xeromezophytes, and the similarity in the structure of anatomical structures indicates closely related relationships in a systematic position