The article presents a variant of the detailed classification of plant resources grouped according to their use, application, types of raw materials and biologically active substances. This classification comprises 13 groups and 66 subgroups with smaller divisions. Examples of plants are given for each classification unit. The role of plants in human life was studied basing on ethnobotanical data on the species available in the collection of the Sochi «Dendrarium». The collected gene pool forms the background for the development of many areas, including forestry with the production of valuable timber species, industries using natural raw materials, alternative energy, agriculture, food industry, forage production, biomaterial science, pharmaceutical industry, the creation of safe and comfortable human habitats in populated areas, the development of domestic tourism, education and raising environmental awareness.

The effect of different illumination levels on the germination of Psidium guajava L. seeds in the greenhouse complex of the Donetsk Botanical Garden was studied. It was determined that a 25 and 50 % decrease in the illumination level reduces the germination of P. guajava seeds by 22.5 % and 42.5 %, whereas the light level of 7124.3 ± 242.7 lux (without shading) facilitates germination of this species in 6,7 days earlier compared to the conditions when it was reduced by 25 % and 50 %. The statistical significance of the illumination level effect on the germination rates in P. guajava seeds was revealed.

The collection of economic valuable plants of the family Lamiaceae of the Donetsk Botanical Garden contains 58 species of aromatic medicinal plants, including 5 official and 28 species indicated as pharmacopoeial. Among the forage and medicinal plants used in veterinary medicine, there are 5 pharmacopoeial species. Herbaceous polycarpics, promising for cultivation in the open ground predominate in the collections. Medical, biological and phytochemical studies of some species, namely Agastache foeniculum (Pursh.) Kuntze, Ziziphora bungeana Lam., Thymus serpillum L. have shown the prospects for their use as potential sources of herbal medicines. The phytoresource potential of the collection of economic valuable plants of the Donetsk Botanical Garden has broad scientific and practical importance in terms of biodiversity conservation and enriching the region with useful plants of the world flora.

The current state of the collection fund of living plants in the Donetsk Botanical Garden and their bioresource significance, the fundamental scientific research areas on adaptation and acclimatization of world flora plants in the conditions of the steppe zone of Russia were analyzed. The directions are given in the research result application and use of collections in educational and environmental education activities, being the most important modern trend in the work of botanical gardens.

Some indicators of phytocenoses were investigated in the artificial steppe laid out 50 years ago in the area of the Donetsk Botanical Garden in comparison to those of different variants of natural steppe areas (petrophytic, typical and cretaceous) of Donbass. A comparative analysis has shown significant differences between the artificial steppe and natural areas in terms of species diversity and species saturation. Floristic diversity of the artificial steppe site is less compared to natural sites, but its species saturation is on the contrary greater. This fact is associated with the man-induced nature of vegetation formation in this area, that confirms its functional purpose – to be a pool for the conservation and reproduction of steppe plant species.

Two autochthonous species such as Noccaea macrantha (Lipsky) F. K. Mey, Phragmites tzvelevii Val. N. Tikhom. and one adventitious species, namely Tinantia erecta (Jacq.) Schetdl. are given for the first time for the flora of Donbass. The original texts of herbarium labels are presented and comments on them are cited.

Based on the own photographic materials published on the Plantarium and iNaturalist websites, 14 species of autochthonous plants are presented for the first time for the flora of the Luhansk People’s Republic, 8 of them are new to the flora of Donbass. Brief information is given on the locations, nature of habitats, and population numbers. A significant proportion (50 %) are rare species located in the Donbass on the border of the species range. The data obtained can be useful for compiling regional floristic summaries and studies on the species composition, distribution and dynamics of the flora of the Donetsk region.

For the time of existence of the Donetsk Botanical Garden, the spontaneous growth in its territory of 35 species, included at various times in the lists of plants subjected to special protection, has been registered. The spontaneous population loci of 11 ones out of them have disappeared by now. But most of the species are present in the collections and expositions, and some actively spread over the territory of the Botanical Garden and «go into the wild» beyond it. The preserved populations of the species native to this territory are of particular value for protection, namely those of: Crocus reticulatus Steven ex Adams, Bellevalia speciosa Woronow ex Grossh., Calophaca wolgarica (L. f.) DC., Delphinium sergii Wissjul., Stipa capillata L., Stipa lessingiana Trin. & Rupr., Tulipa quercetorum Klokov & Zoz, Tulipa ophyophylla Klokov & Zoz., Ranunculus auricomus L., Corydalis solida (L.) Clairv.