Abstract-Environmental aspects of tropho metabolic activity of soil saprophages on the pH buffering capacity of remediated soils in Ukraine was considered. Earthworm (Lumbricidae) casts have been proven experimentally to have a higher acid-base buffering capacity in comparison with that of the initial soil. Remediated soils enriched with earthworm casts become more resistant to negative anthropogenic effects. Thus, the activity of soil saprophages influences positively the environmental properties of remediated soils on forest remediation sites by increasing their buffer capacity.

The flora of the steppe Dnieper region is characterized by an abundance of naturalized alien species, some of which colonised over the last decade. Climate change, associated primarily with increasing temperature, became clearly manifested in this period. We tested the hypothesis that there is an association between climate change and the initiation of invasiveness of some alien plant species in the steppe Dnieper region. For this purpose, comparative studies of the distribution boundaries of naturalized alien trees, shrubs and herbaceous plants were conducted. Along the research route numerous 5-10-year-old broadleaf linden trees (Tilia platyphyllos Scop.) were found in the man-made plantation communities of Dnipro city in areas with moist soil; seeded undergrowth was located at a significant distance from the adult linden plants. Numerous groups of young 7-10-year-old plants of the smoke trees (Cotinus coggygria Scop.), which had a seed origin, were found in the shelterbelt and urban recreational plantations. Young 10-12-year-old virginal and generative plants of the black cherry (Padus serotina Ehrh.) were found in large numbers in both the seminatural and artificial plant communities at great distances from the adult trees. The alien plant species common hackberry (Celtis occidentalis L.) showed the ability to form fairly sparse seminal seedlings, which was presented by the plants at the age of 4-7 years in both the natural and urban plant communities. The perennial herbaceous plant common milkweed (Asclepias syriaca L.) was found in the course of the research in ruderal habitats, urban plant communities, and also in the agrocoenoses. The common milkweed reached its greatest abundance in fields of winter crops, where the spread of this species was accompanied by a sharp decrease in the number of other species of segetal plants. Our study results confirm that the extension of the distribution boundaries of alien species over the last decade was not related to the ground conditions of the steppe Dnieper region. At the same time, changes in climatic conditions were favourable for some naturalized alien species because they have created the opportunity for seed reproduction of species away from the maternal plants. Alien species C. coggigria, P. serotina and A. syriaca were also the most sensitive to the influence of the climate changes. Consequently, these species have the greatest potential for increasing their level of invasiveness and endangering the biodiversity in the steppe Dnieper region under conditions of climate change. We suggest that a simultaneous initiation of invasiveness of these several alien species leads to an increase in the degree of threat to the diversity of natural plants in the region. The study results confirm the urgent need for analysis and forecasting of the consequences of introduction of alien species, in order to prevent the undesirable effects that this would bring for the region's native vegetation.

Plants of the genus Chaenomeles are traditionally used in the countries of South-East Asia, due to their high nutritional and health-promoting properties. However, the successful introduction of species promising for gardening from geographically remote areas requires the study of plant ontogeny under the conditions of new habitat. This is a very substantial problem for the steppe zone, where the continental climate has features of aridity and complicates the process of increasing the diversity of fruit crops by introducing the desired species. The present study aims to assess the effectiveness of the protective enzymatic system of different Chaenomeles genotypes subject to a steppe climate as well as the accumulation of the biologically active compounds with high antioxidant capacity. The study was performed on the basis of the introduced horticultural plants collection in the Botanical Garden of the DNU, and the Chaenomeles fruits, leaves, and the seeds were examined. The highest activity of catalase, benzidine-peroxidase and guaiacol-peroxidase, and the greatest enzymes activation during vegetation were found in leaves of Ch. cathayensis and Ch. speciosa, while the lowest activity was in leaves of both Japanese species. The biggest total phenolic content in the isopropanolic plant extracts, determined by Folin–Ciocalteau assay, was found in leaves of Ch. × superba, Ch. × californica and Ch. cathayensis (44.8, 52.8, and 43.6 mg GAE/g WW); a less high level was found in leaves of Ch. japonica and Ch. japonica var. maulei (43.1 and 40.2 mg GAE/g), while the lowest was in leaves of Ch. speciosa (29.3 mg GAE/g). The total flavonoids content determined using the aluminum chloride method, did not differ by variety or species in the plant leaves, being in the range of 2.6–2.9 mg of RE per g WW (accordingly, in leaves of Ch. japonica var. maulei and Ch. × californica). The high total reducing power determined by potassium ferricyanide assay was found in leaves of both hybridogenic species and Ch. cathayensis (respectively, 11.6, 14.1, and 11.4 AAE/g WW); leaves of both Japanese species had slightly lower values and the lowest was in leaves of Ch. speciosa (7.7 AAE/g). In the Chaenomeles fruits, the total phenolic content was the lowest in Ch. speciosa (17.8 mg GAE/g), average in both Japanese species (28.7 and 27.8 mg GAE/g), and the highest (33.3 mg GAE/g) was in Ch. cathayensis. The flavonoid accumulation was highest in the fruits of Ch. cathayensis and Ch. japonica var. maulei (0.67 and 0.63 mg RE/g), intermediate in both hybridogenic species and Ch. japonica (accordingly, 0.57, 0.42 and 0.38 mg RE/g), and the lowest in Ch. speciosa (0.30 mg RE/g). The total reducing power of Chaenomeles fruit was lower as compared to leaves, and decreased from 11.2 to 5.7 mg AAE/g in the series Ch. cathayensis > Ch. × californica > Ch. japonica > Ch. japonica var. maulei > Ch. × superba > Ch. speciosa. High correlation coefficients between total reducing power and total phenols content in the Chaenomeles leaves and fruits (respectively, r = 0.96 and r = 0.95, P < 0.05) confirm the significant contribution of phenolic compounds to the antioxidant capacity. The study results indicate a high antioxidant capacity of the Chaenomeles species in the conditions of the steppe climate due to the antioxidant enzymes activity and the accumulation of a significant amount of phenolic metabolites in leaves and fruits.

Climatic change can influence the boundaries of the natural and alien plant species distribution. Fluctuations in air temperature, relative humidity and other factors can become a stimulus to initiation and / or intensification of the invasive nature of some adventive plant species, especially in areas with a high degree of anthropogenic transformation. This paper presents an analysis of the current state and a forecast of the invasiveness of the alien species Ulmus pumila L. (Asiatic elm) in the Northern Steppe Dnieper under conditions of climatic change. Two local U. pumila populations consisting of young different age trees were found during a route survey in the territory of the large industrial city Dnipro (48°28′00″ N, 35°01′05″ E) in its left-bank and right-bank parts.The seed origin of both local populations of Asiatic elm is confirmed by the fact that the young plants were spaced at a distance of 50 to 120 m from adult trees, which could potentially be parent plants. Both the left-bank and right-bank populations of U. pumila were located on abandoned construction sites, where there were numerous reinforced concrete slabs, piles and abundant construction debris. In both U. pumila local populations, 100 different-aged trees were randomly selected throughout the site, and their age and the morphometric parameters were measured to simulate the development process of the detected populations, provided the current trends of climate change continue. Analytical dependence of the number of trees in the left-bank local U. pumila population on development time was described by a polynomial model with a determination coefficient of 98.3%. The graphic representation of this model had a sinusoidal character, and a similar dynamic of left-bank population growth in the subsequent years was suggested. The dynamic of the number of trees in the right-bank local Asiatic elm population was described by an exponential model with a determination coefficient of 84.4%, and its graphical representation was exponential. According to the forecast, by 2020, the number of plants in the right-bank local population of U. pumila can increase 4-fold in comparison with 2015 while maintaining the current dynamic of population development. Thus, the created mathematical models adequately described the dynamics of development of both local populations during the last 15 years and predicted their subsequent intensive growth, confirming the initiation and intensification of the invasive nature of the alien species U. pumila by climatic change in the Steppe Dnieper.

The comparative analysis of the fruit and seed capacity of Chaenomeles Lindl., grew in the botanical garden of the Oles Honchar Dnipro National University, was carried out. It is shown that all studied taxa undergo a complete vegetation cycle. According to our observations, the duration of the growing season is as follows: the smallest in Chaenomeles japonica, the longest in C. × superba and C. maulei, the longest in C. speciosa, C. cathayensis and C. californica. Seed length in Chaenomeles plants ranged from 4.2 ± 0.10 mm (C. japonica var. maulei) to 8.5 ± 0.25 mm (C. сathayensis). Seed widths varied from 4.1 ± 0.32 mm (C. cathayensis) to 11.1 ± 0.10 mm (C. japonica var. maulei). According to the results obtained, the average number of seeds in one fruit of different Chaenomeles species differed, decreasing in the following order: C. cathayensis, C. speciosa > C. × californica > C. × superba > C. japonica > C. japonica var. maulei. Most of the Chaenomeles genus representatives were found to be in a good condition: C. japonica var. maulei vitality was estimated at 7 balls, C. japonica and C. × superba – 6 balls. This index is slightly lower for C. speciosa, C. × californica and C. cathayensis as 5 and 4 balls, respectively. It should be noted that the highest vitality was shown by C. japonica var. maulei, which was introduced in the Botanical Garden of DNU in 1955. In research, considerable attention has been paid to the antioxidant system, which is a powerful mechanism preventing the development of avalanche-free and radical peroxide reactions in living organisms. The antioxidant capacity of Chaenomeles fruits, determined in the range from 565.8 ± 15.7 (C. speciosa) to 1121.7 ± 27.5 (C. cathayensis) mg UAE / 100 g DW, can be considered quite high. The overall antioxidant capacity was highest for C. cathayensis fruits (1121.7 ± 27.5 mg AE / 100 g DW), which exceeded the indexes of other species by 1.2–2.0 times. The presence of antioxidants in raw materials and finished products provides for the prevention of their deterioration, reduction of losses, increase the shelf life and release of high quality products, retaining for a long time the characteristic features inherent in fresh, complete products. High taste qualities are characteristic of C. speciosa and C. × californica. Considering the large assortment of Chaenomeles, representatives differing in their biological, physiological and nutritional properties, we consider it promising to introduce their use in the food industry to obtain functional products with high consumer properties, namely, high content of antioxidants, catering for a variety of dishes or for exotic flavors, as well for direct consumption by the population of useful fruits with different flavors.

Plant fruits, leaves, stems, and other parts are of high nutritional value, and are the source of physiologically active compounds, which can contribute to the treatment of many diseases caused by oxidative stress. Enrichment of the species spectrum of the fruit plants expands the possibilities of their use in dietary nutrition and human treatment. Unfortunately, the introduction of the new fruit plant species in industrial gardens in the Steppe Dnieper is limited to a large extent by the unfavorable climate. In this regard, the assessment of the possibility of realizing the genetic potential of fruit plants from different geographical areas in the steppe climate acquires both scientific and practical significance. The study was conducted on the basis of the fruit plants collection collection of the Botanical Garden of the DNU including four introduced species and one natural species from the genus Berberis. The anomalous weather conditions during the growing season of 2017 (snowfall in April followed by a drought in June) were accompanied by an earlier stage appearance of leaves, flowering and fruit ripening of all introduced plants, especially the Asian species B. amurensis and B. koreana, compared to the native species B. vulgaris. In accordance with the results obtained, fresh weight of the ripe fruits of Berberis species decreased in the order of B. amurensis > B. vulgaris > B. canadensis > B. koreana > B. x declinata. The highest total phenolics content, determined in the isopropanolic fruit extracts by Folin – Ciocalteau assay, was found in the fresh ripe fruits of B. koreana (1362 ± 66 mg GAE/100 g WW), followed by B. x declinata and B. vulgaris fruits (91% and 77% of the B. koreana phenolics content respectively). The highest total flavonoids content determined using the aluminum chloride method was revealed in the fruits of B. koreana (210 ± 6 mg RE/100 g FW) exceeding the content in fruits of other Berberis species by 1.1–2.1 times, while the lowest value (103 ± 4 mg RE/100 g FW) was found in the fruits of B. amurensis. The total reducing power, determined by RP assay, varied in the range from 5.0 to 9.6 mg AAE/100 g DW, and the highest levels were found in the fruits of B. koreana and B. x declinata (respectively, 9.6 ± 0.6 and 8.6 ± 0.5 mg AE/100 g DW) exceeding the reducing capacity of other Berberis species by 1.7–1.9 times. In the fruits of genus Berberis species strong positive correlation was found between the total reducing power and the total content of phenols (r = 0.87), as well as between the reducing power and the total content of flavonoids (r = 0.84). High correlation coefficients confirm the significant contribution of the Berberis fruit phenolic compounds, including the flavonoids, to the antioxidant capacity. So, the study results showed that fruits of all examined Berberis species can be an easily accessible source of antioxidants, however, the antioxidant capacity of fruits decreased in order of B. koreana > B. x declinata > B. vulgaris > B. amurensis > B. canadensis.

The paper presents the results of studying fruits antioxidant properties of several species, previously combined into the genus Sorbus L. (Rosaceae family). Ripe fruits were collected in September 2020 from the plants of Cormus domestica (L.) Spach, Sorbus aucuparia L., Karpatiosorbus latifolia (Lam.) Sennikov & Kurtto and Torminalis glaberrima (Gand.) Sennikov & Kurtto from the collection of the Botanical Garden of the Oles Honchar Dnipro National University. Total phenolic content (TPC), total flavonoids content (TFC), ferric reducing antioxidant power (FRAP) and total antioxidant capacity (TAC) were determined both in the fruits peel and pulp. In the fruits of all species, higher values of the determined indicators were found in the fruit peel than in the pulp. Moderate and strong positive correlation was found between FRAP and TPC as well between FRAP and TFC both in peel and pulp of all studied species. At the same time, notable interspecific differences of the phytochemical traits were established, indirectly confirming the ambiguity of the taxonomy of the genus Sorbus L. According to the fruits antioxidant properties and secondary metabolites accumulation, species K. latifolia (broad-leaved whitebeam) and T. glaberrima (wild service-tree) are the most promising for cultivation in arid conditions of the central steppe of Ukraine.

The decline in the global biodiversity and the increase in the number of threatened plant species are the extremely unfavorable trends over the past decades. These phenomena determined the need for the thorough and detailed study of the plant population resistance mechanisms, and the development of the methods to predict the risks of their extinction. In the recent years, simultaneous assessment of the ontogenetic and the vital structure of the populations has become the most recognized method of studying populations. This approach has provided a significant increase in the reliability assessment of the population status and led to improved predictions of their dynamics. However, there are a limited number of the papers containing the complex demographic analysis, including the field size of the population, the number of individuals in the population, the population density, as well as genetic, ontogenetic, and vital structure of the populations with their dynamics. The purpose of this work was to determine the current state and to predict the possible trends in the status of seven rare plant species' populations located on the territory of the National Nature Park "Desnyansko-Starogutsky" (Sumy province, Ukraine).Rare plants Epipactis helleborine (L.) Crantz, Lilium martogon L., Listera ovata (L.) R. Br., Platanthera chlorantha (Cust.) Rchb., and Pulsatilla patens (L.) Mill. are the species listed in the Red Book of Ukraine. Plant species Circaea alpina L. and Pyrola chlorantha Sw. are designated as the rare species on the territory of Sumy region. Integral estimation of the population status has based on the determination of such parameters as population size, population density, the ontogenetic index, and the index of the population vitality. Correlation analysis revealed a high level of correlation (r = 0. 99) not between everyone, but between some of the population parameters only. In our study, the indices that characterize the ontogenetic structure of the populations were the most frequently correlated: renewal index, generative index, as well as indexes of the population age (Δ) and the effectiveness of the population (ω). The regression analysis revealed that the long-term monitoring of the rare plant populations will be an integral character in the case of accounting for such factors as the population size and density dynamics over the years, changes in the population vitality (Q), and the annual changes of the magnitude of ω, which integrates the ontogenetic structure of the populations. It has been established that the populations of L. martagon from the phytocenoses of Pinetum coryloso-maіanthemosum and Fraxinetum coryloso-convallariosum were stable enough together with the progressive development trend. The populations of the rare species C. alpina, L. martagon (habitat between Betuleta corylosa and Pineta corylosa-convallariosum), and P. patens were estimated as the sustainable. A clear tendency toward a decrease in the individuals' number was found in rare species represented by only one populati...