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.

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 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.

The study focuses on in vitro effect of aqueous tinctures of 48 species of herbaceous, shrub and tree plants on the first-third stage larvae of Strongyloides papillosus (Wedl, 1856) and third-stage larvae of Haemonchus contortus (Rudolphi, 1803) Cobb, 1898. The highest level of the effect was exerted by 3% aqueous tinctures of Wisteria sinensis (Sims) DC., Ailanthus altissima (Mill.) Swingle, Laburnum anagyroides Medik., Quercus petraea subsp. iberica (Steven ex M. Bieb.) Krassiln., Ginkgo biloba L., Colchicum autumnale L., Aristolochia manshuriensis Kom., Celastrus scandens L., Securigera varia (L.) Lassen, Magnolia kobus DC. Over 90% of the first and second non-invasive stage larvae of S. papillosus died at contact with these tinctures. The lowest parameters of LD50 were seen for L. anagyroides, Juniperus sabina L., C. scandens, M. kobus, A. manshuriensis, Wisteria sinensis (Sims) DC. and Securigera varia (L.) Lassen. Invasive larvae of S. papillosus and H. contortus were resistant to the effect of all the 48 surveyed species of plants. Third-stage larvae of H. contortus remained vital when exposed for 24 h to all the studied concentrations up to 3% aqueous tincture of plants. The results of the experiments and also the analysis of the literature indicate the necessity to continue the survey on nematocidial activity of aqueous tinctures and alcveshol extracts of plants.

Parameters of peroxidase complex are indicators of the adaptable processes which are taking place in plants under the environment influence. In this work the general activity dynamics and peroxidase isoenzyme composition in vegetative organs of Japanese quince (Chaenomeles Lindl.) were studied. The four species introduced in a steppe zone of Ukraine were researched: Ch. japonica (Thunb.) Lindl., Ch. speciosa (Sweet) Nak., Ch. cathayensis (Hemsl.) Schneid., Ch. × superba (Frahm) Red.). It was determined that the enzyme activity of these species possesses specific features subject to the phases of seasonal development and in response to the action of the hydrothermal stress. The highest enzyme activity in the period of intensive growth and flowering, with a subsequent sharp drop towards the middle of summer and further smoother decrease during the phase of physiological rest were observed in the leaves of Ch. speciosa and Ch. cathayensis. A higher peroxidase activity was a characteristic of Ch. japonica and Ch. × superba in the middle of the vegetative period, which can be considered a display of adaptation processes in the conditions of an unfavourable hydrothermal regime. The dynamics of changes in the quantitative composition of isoperoxidases was similar to the dynamics of enzyme activity. As a result of the generalization of the obtained data it is possible to consider that Ch. japonica and Ch. × superba are the steadiest in the conditions of the region.