The analysis of the dynamics of the parameters of the water regime (water content and real water deficit) in the leaves of four species of the genus Quercus L. during the summer seasons of 2022 and 2023 was carried out. It was revealed that the leaves of Quercus ilex were characterized by the lowest water content. This species, regardless of weather conditions, has a consistently low level of real water scarcity. Under controlled conditions, with various combinations of temperature and humidity, it was found that the leaves of Quercus рubescens have the lowest water retention forces, and their maximum level was detected in Quercus ilex. The boundaries of sublethal water deficiency in the studied species of the genus Quercus were determined: Quercus рubescens - 15-16 %, Quercus robur and Quercus petraea – 20-22 %, and Quercus ilex – 30 %. Data on changes in the permeability of cell membranes under the influence of various combinations of temperature and humidity have been obtained. It has been shown that in conditions close to dry, irreversible cell membrane disorders occur in deciduous species of the genus Quercus against the background of an increase in the rate of dehydration. The change in the intensity of exosmosis in Q. ilex, under such conditions, was poorly expressed, which characterizes its high drought resistance.

   Plants of the genus Arnica (Arnica L.) are perennial herbaceous species growing in the forest meadows of Western and Central Europe and successfully introduced into the Arctic zone of the Russian Federation. The inflorescences of arnica plants have anti-inflammatory, analgesic, antioxidant, anti-osteoporosis, anxiolytic, immunomodulatory, protective, and anticancer properties due to the synthesis of a significant number of secondary metabolites. As a result of the intensive collection of mountain arnica as medicinal raw materials, this species is currently listed in the Red Book of the International Union for the Conservation of Nature and Natural Resources, which necessitates the identification of species that are not inferior in phenolic compounds and the creation of a raw material base in order to provide raw materials for the production of phytopreparations from arnica plants.

   Thus, the purpose of this work was to determine the total content of phenolic compounds in aqueous extracts of plants of the genus Arnica L. growing under conditions of introduction in an open introduction nursery of perennial herbaceous plants of the Polar Alpine Botanical Garden-Institute named after A.N.

   Avrorin of the KSC RAS in the Kirovsky district of the Murmansk region. In accordance with the Regulation of the European Union No. 1907/2006, "Registration, assessment, authorization and restriction of chemicals", adopted on 12/16/2008, PNST 331 – 2018 "Green" standards. "Green" products and "green" technologies. Classification, adopted on December 25, 2018 and amendments to Federal Law No. 61 of the Russian Federation "On the Circulation of Medicines", adopted on 08.08.2024, aqueous extracts of inflorescences of various types of arnica plants were obtained by ultrasonic extraction. The total content of polyphenols and flavonoids was determined. The largest amount of polyphenols and flavonoids was found in extracts of Arnica longifolia and Arnica mollis inflorescences, respectively. The results obtained can be used in the pharmaceutical and cosmetology industries.

   In the research article presents data on biochemical characterization of fruits and seeds of Opuntia engelmannii Salm-Dyck ex Engelm. subsp. lindheimeri (Engelm.) U. Guzmán & Mandujano naturalized in natural phytocenoses within the Southern Coast of Crimea. It is shown that in the conditions of subtropical Mediterranean climate type, opuntia plants are characterized by smaller morphological parameters in comparison with plants from natural habitats: they reach a height of 0.7 m, cladodes up to 30 cm long, 20 cm wide, 0.8-1.1 cm thick, fruits up to 7.2 cm long, 3.5 cm wide and seeds up to 3.9 mm long, 3.8 mm wide. An average of 6 ± 2 fruits are formed per plant and seed production consist of 1200 ± 120. The method of photocolorimetry revealed that opuntia fruits contain 0.53 ± 0.1 % proteins, 8.57 ± 1.2 % carbohydrates, 12.1 ± 1.0 mg % of vitamin C, which indicates their high nutritional value. The content of fatty oil in seeds is 11 % (according to literature data oil content varies from 9.3 to 11.45 %). The fatty oil is characterized by a high proportion of unsaturated acids (84.8 %), which indicates its value for use in cosmetology. The presence of vaccenic acid, which has the properties of reducing cholesterol and enhancing antitumor immunity, substantiates the pharmacological value of opuntia oil.

   Currently, wild essential oil plants are of significant interest for their study as sources for obtaining individual components (substances of the class of terpenes and phenols, biologically active compounds such as thymol, carvacrol, menthol, linalool, etc.) and subsequent introduction and plantation cultivation. The search must be carried out among wild species of such families as Lamiaceae = Labiatae, Asteraceae = Compositae, Apiaceae = Umbelliferae, Rutaceae, Lauraceae, Alliaceae, Asphodeliaceae. Enrichment of the modern assortment with wild and cultivated essential oil plants for the purpose of creating a domestic raw material base is currently relevant. To successfully introduce new species into culture, it is important to initially study the specific biology of the species (ontogenesis, anecology, raw material and seed productivity, composition of essential oil components). Ways are proposed to study the identified new and promising species, develop agricultural techniques for their cultivation and create industrial plantations. The possibilities of using essential oil plants and essential oils for the treatment and prevention of infectious diseases, including viral and fungal ones, for the sanitation of premises and the fight against nosocomial infections, as well as for the comprehensive protection of plants from various pests and diseases are being considered.

   Essential oils (EO) are multicomponent mixtures of terpenes, terpenoids, and aromatic hydrocarbons. The creation of therapeutic agents based on EO requires an assessment of the role of each component in the action of the EO. One possible way is to identify a correlation between the content of the component in the EO and the severity of the biological effect.

   Objective. To evaluate the role of some components in the effect of EO on the human body based on the study of the correlation between the content of the component in EO and the severity of the effect.

   Materials and methods. Women 55-85 years old. The control groups underwent psychorelaxation lasting 10, 20 or 30 minutes, the experimental groups underwent psychorelaxation in combination with inhalation of the EO at a concentration of 1 mg/ m³ of air, the same duration. Before and after the procedures, systolic (SBP) and diastolic (DBP) blood pressure, heart rate (HR) were measured, stroke volume of the heart (HSV), cardiac minute output (CMO), blood circulation efficiency coefficient (CEC), psychoemotional state (Hospital Scale of Anxiety and Depression) and mental performance (the missing letters test).

   Results. Upon 10-minute exposure, the content of p-cymene in the EO positively correlates with the HSV and CMO and negatively with the level of depression, β–pinene - positively with the HSV, CMO and CEC, limonene - negatively with heart rate. After 20 minutes of exposure, the p-cymene content positively correlates with CMO and with word recognition. After 30 minutes of exposure, the content of p-cymene is negative, and 1,8-cineole positively correlates with the level of depression, the content of linalool is negative with word recognition. No statistically significant correlations were found for α-pinene.

   Conclusion. p-cymene has a positive effect on psychoemotional state, mental performance and blood circulation, linalool has a negative effect on mental performance, 1,8-cineol has a positive effect on psychoemotional state, limonene and β-pinene have an ambiguous effect on blood circulation.

   Lawns are integral elements of landscaping of landscape architecture objects. Rational selection of the assortment allows creating economical, long-term, highly decorative plant coverings in specific soil and climatic conditions. The coastal zone of the Southeastern Crimea is extremely unfavorable for creating lawn coverings due to low humidity, high summer temperatures, heavy low-fertility waterproof soils, salinization. The article analyzes classical and modern works on creating lawns and the range of lawn grasses in relation to the conditions of the southern arid and semi-arid regions. A basic range of lawn grasses has been developed, including 9 species and 3 forms, for creating lawns for various purposes in the coastal zone of the Southeastern Crimea. For the arrangement of parterre and ordinary lawns of class I quality with a high level of technology for creation and care, it is proposed to use grass mixtures of long-term low-lying cereals resistant to low mowing. Lawn coverings for sports facilities must be resistant to trampling and frequent mowing. They can be created from a mixture of Lolium perenne L. cultivars or a grass mixture with Festuca rubra L. ssp. rubra, F. rubra var. commutata Gaudin, F. rubra var. trichophilla Ducros tx Gaud., Poa angustifolia L., Lolium perenne L. Ordinary lawns of quality class II with a high level of technology of installation and subsequent periodic irrigation can be created from grass mixtures, the components of which are undemanding to environmental factors and resistant to negative factors. For turf covering for special purposes without irrigation and rare high mowing, cereals of local flora can be used.

   The article provides a comparative assessment of the microclimate features on seaside of the Nikitsky Botanical Gardens around of the cactus greenhouse according to instrumental meteorological observations of the Montedor point and the Nikitsky Sad reference agrometeorological station. As a result of the conducted research, the homogeneity and spatial-temporal connectivity of climatic parameters within the studied territory has been established. According to the results of the study, it was revealed that in the seaside of the Nikitsky Botanical Gardens, the sum of active temperatures in active vegetation period is 345 °C higher, and the number of days with extremely high temperatures is 3-4 times more than at altitudes of about 200 m above sea level. During the summer period, stock phenomena are characteristic at night, causing the air temperature to drop 2-3 °C lower compared to areas located 155 m above. Vertical gradients of air temperature on the Southern Coast of Crimea in modern climatic conditions have been determined and their statistical assessment has been performed. The possibility of using them to calculate the air temperature in the area of Big Yalta in the altitude range from 50 to 1200 m above sea level is shown.

   The characteristic of the model profile laid down on Mount Opuk in 1988 from sea level to the northwestern slope, in comparison with the studies of 2023, is presented. The assessment of the ecotope conditions at the description sites was carried out using a specially developed "Pover" program. The realized fragment of the gradient and the optimum point on it were determined for the leading factors-conditions and resource factors: illumination-shading, thermal mode, aridity-humidity (ombre mode), cryoregime, continentality, humidification, variability of humidification, substrate acidity, salt regime (anionic composition), carbonate content, nitrogen content, substrate porosity. It was found that during the period from 1988 to 2023, with a total length of 35 years, the conditions on the gradients of the environmental factors of the edafotope did not change, the climate also did not change as a whole, but small deviations were noted. The changes that have occurred on the gradients forming the realized ecological niche of phytocenoses are reflected in changes in the floral composition, as well as biomorphological and ecological indicators. The floral composition is undergoing changes, and in some areas the transformation covers more than half of the species, especially in areas with high activity of modern exogenous geomorphological processes. The proportion of resident species that controls resources has increased significantly, while the number of plants that prefer disturbed ecotopes has decreased markedly, which indicates the positive impact of the conservation regime. The analysis of the floral composition, biomorphological and ecological characteristics of the phytocenosis demonstrates the need to continue monitoring the processes of transformation of the reserve's ecosystem. The results obtained contribute to a deeper understanding of the changes taking place in plant communities under the influence of various factors, including climate change and anthropogenic impact. Special attention is paid to the importance of long-term observations of the dynamics of natural communities, as well as consideration of effective methods and approaches for studying such changes.