Representatives of the genus Hedera L. have been cultivated in the Nikitsky Botanical Gardens over two centuries. The article describes the main stages of the collection formation, as well as its current state. The inventory of the collection has revealed four species, forty six cultivars, of which three species and four cultivars have reached the generative stage, and the rest of the cultivars are at the juvenile stage of development. It has been established that the collection contains representatives from all nine garden groups allocated for ivy. The cultivars are described by the main morpho-decorative characteristics. Two groups are distinguished by the color of the leaf blade. Six groups are distinguished by the type of color; five groups among species and cultivars - by the shape of leaf blades; two groups - by the type of growth.

The article presents the results of studies of the effectiveness of a biological preparation of arbuscular mycorrhizal fungi on promising cultivars of four essential oil crops, such as ʹIzumrudʹ Artemisia dracunculus L.; ʹRekordʹ Lavandula angustifolia L.; ʹNikitsky belyʹ Hyssopus officinalis L. and ʹNovichokʹ Artemisia annua L. As an evaluation criterion, the morpho-biological and economically valuable traits of plants, such as the yield of the aboveground mass, the mass fraction of essential oil in the raw material and its biochemical composition, were studied in the work. Inoculation of herbaceous plants (sweet wormwood ʹNovichokʹ cultivar, tarragon ʹIzumrudʹ cultivar) delayed the phases of generative development for 4-13 days, positively affecting the length of inflorescences, which improved all economically valuable indicators with significant differences in plant height, yield and collection of essential oil. Semi-shrub crops (narrow-leaved lavender ʹRekordʹ cultivar and medicinal hyssop ʹNikitsky belyʹ cultivar) reacted to the presence of mycorrhizal fungi to a lesser extent. A shorter period of stay from the budding phase to the mass flowering phase of these cultivars in the experiment did not contribute to the growth of vegetative mass, and the introduction of arbuscular mycorrhizal fungi led to an increase in the number of inflorescences (1.5 times in lavender) and a significant advantage of their length. The changed growing conditions, due to an increase in the proportion of inflorescences in floral and herbaceous raw materials, have made adjustments to the biochemical composition of essential oils of all crops. Over the years, there is a stable positive trend in its main components: in lavender oil - by linalyl acetate, in tarragon oil - by methylhavicol and in sweet wormwood - by the sum of camphor and eucalyptol. In the conditions of the SSC, among the studied cultivars, ʹNikitsky belyʹ showed the weakest responsiveness.

By chromate-mass spectrometer method it was positioned the qualitative and quantitative maintenance of terpeneʹs components in hexane extracts obtained from plant samples of Artemisia balchanorum Krasch, corresponded to all phases of its vegetation. The relative graphic-analytical and template analyses of the received experimental and modelling settlement data based on own methodical approaches are carried out. One determined the kinetic dependences for a dynamical accumulation of monoterpeneʹs components in investigated plants according to degrees of ring formation to study the influence of a plastid membrane on the kinetic characteristics of the bicyclic monoterpenes formation, and also to obtain the data of the biosynthesis localization of acyclic and monocyclic monoterpenes in a plant cell.

Invasive species are the most aggressive group of adventive plant species brought from other physical and geographical regions, and often continents. Special attention to the study of invasion processes taking place on the territory of the Orenburg region was reflected in scientific publications of the last 10 years. The north-west of the Orenburg region, like the southern regions of the Republic of Tatarstan, remains poorly studied in terms of invasion processes by regions. Expeditionary studies carried out in 2021 in 5 districts of the Orenburg region and 3 districts of the Republic of Tatarstan made it possible to significantly expand knowledge about the distribution and ecology of invasive plant species. A total of 171 locations of 19 invasive and potentially invasive plant species were identified. According to their invasive status, 7 species ( Ambrosia trifida, Bidens frondosa, Echinocystis lobata, Heracleum sosnowskyi, Hordeum jubatum, Iva xanthiifolia, Xanthium albinum ) have 1 status. 3 species ( Impatiens glandulifera, Sambucus racemosa, Urtica cannabina ) - 2 statuses. 7 species ( Amaranthus albus, Amaranthus blitoides, Bassia scoparia, Cuscuta campestris, Portulaca oleracea, Senecio viscosus, Sisymbrium volgense ) - 3 statuses. 2 species ( Ballota nigra and Thladiantha dubia ) are potentially invasive plants and are included in the group with 4 statuses. The largest number of locales of invasive plant species is characteristic of the northwestern regions of the Orenburg region. A significantly smaller number of invasive species were detected in neighboring regions of Tatarstan. Ambrosia trifida, Echinocystis lobata and Iva xanthiifolia are the most common invasive species in the region. Undoubtedly, wood invasive plants ( Acer negundo ) have great damage to the biodiversity of the region. This species occurs on most small steppe rivers and becomes a characteristic species of floodplain forests.

Xanthium albinum (Widder) H. Scholtz) is an invasive species, widespread in various conditions of the Piedmont Crimea. In 2021 morphometric features (plant height, shoot diameter, number of leaves, leaf length and width, number and diameter of male anthodia, number of mature collective fruits, length and width of collective fruits) were studied in eight cenopopulations. The results of the correlation analysis between the studied parameters as well as the features of their general and consistent variability are presented. The traits were selected for the analysis of the vital structure with the allocation of ecological-biological, biological and genotypic indicators. The vital structure is characterized based on the analysis of ecological and biological indicator traits. The dependence of the morphological integration of the species on the growing conditions has been studied. It was found that in most of the studied cenopopulations in the vital structure, the species showed a depressive and close to equilibrial tendency.

The results of long-term geobotanical studies (based on 2756 descriptions) in the subalpine meadow ecosystems of Kabardino-Balkaria were summarized. 84 species were identified as indicators of pasture digression and/or post-pasture restoration of mesophytic, semi-arid meadows and meadow steppes. Among them there are 11 grazing resistant forage species; 24 grazing unstable forage species; 38 poorly eaten species; nine non-edible poisonous species. The projective coverage of the species at different levels of pasture load was revealed. The presented generalized background information is the basis for assessing the state of plant communities in the Central Caucasus.

The article presents the results of studies of the adaptability of strawberries to the negative factors of the summer period, as well as the functional ability to recover from stress. By the method of cluster analysis based on euclidean distance a comparative assessment of water-retaining forces and the possibility of maximum repair of leaf tissues of cultivars and forms is given. The best initial forms for obtaining drought-resistant strawberry plants - Krymchanka 87, Amelia, Assol, Zarina, Sanika, Sunrise, which are recommended for further use in breeding and introduction into production, are noted. The most promising hybrid forms 4-15 (Atlantida × Honey), 12-15 (Sunrise × Hercules), 13-15 (Sunrise × Zenga Zengana), 25-15 (Yantarnaya × Zenga Zengana) with increased resistance to extreme climatic conditions are identified.

The article analyzes the scientific and technical literature, identifies trends in the world production of plums and cherry plums. Plum and cherry plum are one of the most cultivated fruit crops in the world. In terms of cultivation area, they surpass such crops as: pear, peach and nectarine, apricot, cherry, and are second only to apple, orange and banana. In the period from 1994 to 2018, there was a slight increase in the area (from 1.6 million hectares to 2.6 million hectares, respectively), in turn, due to the introduction of new agricultural techniques, the yield of plums and cherry plums changed significantly, from 6.3 million hectares. tons up to 12.6 million tons, respectively. The main producing regions of this crop are Asia (60.4% of world production), Europe (25.9%), America (10.5%). Africa (2.9%) and Oceania (0.3%) make an insignificant contribution to the world production of plums and cherry plums. The leading plum and cherry plum producing countries are China, Romania, Serbia, USA, Iran, Turkey, India, Chile, Morocco and Ukraine. The most efficient plum and cherry plum production was noted in Israel and Italy (17.4 and 16.9%, respectively). Every year there is an increase in the growth rate of plum and cherry plum cultivation in the world. The areas of plantings, gross harvest and crop yields are increasing. This is evidenced by the introduction of new highly productive cultivars, the use of modern agricultural techniques with high planting density.

We studied the frost resistance of 30 apricot forms of the Nikitsky Botanical Gardensʹ breeding. Five forms distinguished themselves by high frost resistance: 8316, 84-475, 84-803, 84-875, 89-526. Six forms had the increased frost-resistance: 0-11, 24-86, 84-679, 84-784, 84-890, 84-986. Our research has shown these forms can be used in breeding for frost-resistance. Studies on freezing in climate chambers have demonstrated that degree of frost resistance depends on the stages and rates of development of flower buds. Forms with slow rates of development of fruit buds are characterized by greater frost resistance: 84-784, 84-803, 84-895.

The article presents the results of a study of 31 cultivars, 10 forms and seven hybrid seedlings of peach bred in the Nikitsky Botanical Gardens in terms of frost resistance of flower buds. As a result of artificial freezing of shoots in the climatic test chamber TTS 256 Memmert C PO in various phases of morphogenesis of flower buds 26.03.19 at a temperature of -3°C; 01.20.2020 - -16°С, 02.13.20 - -20°С, 03.03.20 - -12°С, 25.01.21 - -20°С, 24.02.21 - -16°С with increased resistance to negative temperatures in winter - spring period, seven cultivars and forms were identified: Nikitsky Podarok, Sarabuz, Serdolik, Gartvis-72, Karnaval'ny, Lebedev x Babygold-5 γc 20 97-90, Zlatogor x Uspar-1 80-367., as well as three hybrid seedlings: Veteran x Madlen Puiet 92-1648, (Druzhba Narodov x Babygold-5 γc 60) 97-175 and Valiant x Favorita Morettini 80-431, 92-1944. The marked samples are sources of frost resistance and are promising for use in hybridization and further breeding work.

The article describes the problems of industrial walnut cultivation on the territory of the Russian Federation, namely, the lack of development of vegetative reproduction of this crop, as well as possible ways to solve these problems. Possible rootstocks for the production of walnut seedlings are described. As an intensification of production, a rootstock of black walnut seedlings and the possibility of optimizing its mother-seed stock areas were proposed, which will reduce the area of nutrition of one tree, thereby increasing the density of plantings, speeding up the entry of walnut plantations into industrial fruiting.

The article presents the results of studying the suitability of fruits of various cultivars and forms of apple trees for the production of applesauce and high-quality dried fruit products by the method of solar drying. When selecting apple fruits as a source of valuable raw materials for processing, the chemical composition plays an important role. Compliance with the chemical composition of fruits does not always guarantee the receipt of processed products with high tasting qualities. In the course of the work, cultivars and forms were identified, the fruits of which are most suitable for obtaining applesauce (autumn ripening period - Priam, Eder, 3-5-C; winter ripening period - Idared, Ligol, Pinova, Rhubarb, Rubin, Eder, 2-2-65-80, 10-99-78, 61-74). Analysis of the data obtained in the production of dried fruit products allowed us to identify cultivars whose fruits are most suitable for this type of processing: Krymskoe, Ligol, Pinova, Priam, Rubin, 1-8, 2-2-65-80, 3-5-C. The content of ascorbic acid in the resulting products was determined - from 11.7 to 14.7 mg /100g. The level of titrated acids in dried fruits ranged from 0.84 to 1.39%, and did not depend on the maturation time of the samples. In the group of cultivars of columnar apple trees, Pioner cultivar distinguished itself by a combination of features that are valuable in the preparation of dried fruit products. The obtained data allow us to recommend the selected cultivars and forms for studying their suitability for other types of processing.

The article presents data on the study of biological and morphological characteristics of 15 cultivars of tree paeonia during introduction in the conditions of the forest-steppe zone of the Bashkir Cis-Ural. 13 quantitative and 21 qualitative features were analyzed. Their research was carried out in accordance with the «Test methodology for distinctness, uniformity and stability». The phenotypic variability of quantitative parameters was studied. High variability was found for the traits «maximum plant height», «shoot regrowth length» and «pedicel length», medium - for «maximum shoot thickness», «length and width of the leaf at the first axillary bud», «maximum peduncle thickness», «flower diameter». A positive high correlation was noted between the flower diameter and the length of the longest tepal (0.75). The revealed patterns are of interest for building a model of paeonia cultivars and using them in plant breeding.

Seasonal dynamics of 25 elements concentrations in Karadag groundwater was evaluated. Increased levels of B, Li and Se were recorded, along with negative correlations between water mineralization and both flow rate of springs and the distance from the seashore (r = -0.840 and r = -0.945), as well as high seasonal variations of P and K levels (78-130% and 80-118% respectively). Positive correlations were found between Ca, Mg, Sr (r = 0.82-0.96); Li, B, Na (r = 0.72-0.90); Li, Na, mineralization (r = 0.80-0.90) and Se, Na (r = 0.551). The highest concentrations of P, K, Si, Na were registered in spring, B, Zn, Fe, Se, F in autumn; Са, Se, F, Cl, I in winter, and Sr in spring and autumn. Ca, K, Mg, Na, B, Fe, Li, mineralization and water hardness of Bio-station well water demonstrated high seasonal variations and maximum permissible concentrations excess.