Preservation of some rare species of natural flora in the Subtropical Scientific Centre of the Russian Academy of Sciences

. Conservation issues related to biological diversity, especially rare and endangered plant species, remain among the most pressing challenges. Scientific institutions and botanical gardens play a crucial role in addressing this problem. The Federal Research Centre "Subtropical Scientific Centre of the Russian Academy of Sciences" (FRC SSC RAS) has been actively involved in the study of natural flora, including rare species, since the mid-1990s. The objective of these studies was to explore 48 rare plant species belonging to 34 genera from the families Boraginaceae, Ranunculaceae, Asparagaceae, Amaryllidaceae, Asteraceae, Orchidaceae, and Iridaceae in the conditions of the humid subtropics of Russia. The research revealed that the studied species are perennial herbaceous plants with high decorative qualities. Among them, 29 % are rhizomatous, 23 % are bulbous, 21 % are cormous, 19 % are short-rhizomatous, and 8% are tree-like. Phenological observations indicated that all species flowered, and almost all bore fruits. Winter-flowering species constituted 10% of the collection, spring-flowering species – 48 %, summer-flowering species – 31 %, and autumn-flowering species – 10 %. The studied plant species have various conservation statuses, with 16 species listed in the Red Books of the Russian Federation, 24 in the Krasnodar region, 20 in Sochi, 36 in other regions of the Russian Federation, and 20 on the IUCN Red List. Fourteen species are identified as rare and endemic.


Introduction
The urgency of preserving biodiversity remains a critical issue.Currently, particular importance is placed on the conservation of rare and endangered plant species.Scientific institutions and botanical gardens play a significant role in addressing this concern by establishing, maintaining, supporting, and studying genetic plant collections, including those containing rare species.Very often, these measures have a positive impact [1][2][3][4][5][6][7].
A large number of rare and endangered plant species belong to the families Orchidaceae Juss., Iridaceae Juss., Asparagaceae Juss., Amaryllidaceae J. St.-Hil., and others.Many of them are included in the Red List of the IUCN (International Union for Conservation of Nature and Natural Resources) and have conservation statuses in practically all regions of the Russian Federation [8][9][10][11][12][13].
The territory of the Northwestern Caucasus is characterized by significant floristic diversity.For example, in the Sochi Black Sea region, the Orchidaceae family is represented by 52 taxa, of which 46 are rare.The Red Book of the Krasnodar region includes 16 species from the Amaryllidaceae family, 10 from Iridaceae, and 7 from Asparagaceae [14].
The study of natural flora, including rare species, at the Federal Research Centre "Subtropical Scientific Centre of the Russian Academy of Sciences" (FRC SSC RAS) began in the mid-1990s.During that period, a plant collection was established, consisting of specimens collected from their natural habitats.Subsequent research involved the study of these specimens, and methods for the accelerated propagation of many species were developed.

Materials and methods
The research was conducted on bioresearch collections of natural flora species and irises located in experimental plots of the Federal Research Centre "Subtropical Scientific Centre of the Russian Academy of Sciences" in the village of Razdolnoye, Khostinsky district, city of Sochi.
The objective of the research was to study rare plants from the families Boraginaceae Juss, Ranunculaceae Juss., Asparagaceae, Amaryllidaceae, Asteraceae Bercht.& J. Presl., Orchidaceae, Iridaceae under the conditions of humid subtropics in Russia.The study of 48 species (Figure 1) was conducted using established methodologies.
The climatic conditions of the region are unique and correspond to a Mediterranean type.Winters are characterized by relatively warm and rainy weather, springs are cool and humid, summers are hot and dry, and autumns are warm and dry.

Results
As a result of the conducted research, it was determined that the studied species from the bioresearch collection of the Federal Research Centre "Subtropical Scientific Centre of the Russian Academy of Sciences" are perennial herbaceous polycarpics.The majority of the species are rhizomatous plants -29 %, followed by bulbous -23 %, cormous -21 %, and  Phenological observations of rare plants in the bioresearch collection of the Center revealed that all species flowered, and nearly all bore fruit.It was noted that the majority of species belonged to spring-flowering plants -48 %, followed by summer-flowering -31 %, and autumn-and winter-flowering each constituting 10 % (Figure 3).The studied plant species are classified as rare, and they are listed in the Red Books of the Russian Federation (16 species), Krasnodar region (24 species), Sochi (20 species), and other regions of the Russian Federation (36 species) (Table 1).A substantial number of species are included in the Red List of the International Union for Conservation of Nature and Natural Resources (IUCN) -20.It is noteworthy that many of these species hold a critical conservation status, with a high risk of extinction in several regions.A significant portion of these species is listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), indicating they are under threat.
Furthermore, the studied plant species exhibit endemism (7), relict status (6), with one species belonging to both endemic and relict categories.

Conclusion
Thus, the conservation and maintenance of the biological diversity of rare species of natural flora, supported at the Federal Research Centre "Subtropical Scientific Centre of the Russian Academy of Sciences" (FRC SSC RAS), are focused on their preservation, cultivation, as well as the introduction into cultivation and the development of conservation strategies for unique, rare, and endemic plant species.It has been established that among the 48 studied rare species of natural flora, 29 % are rhizomatous perennial herbaceous

Fig. 2 .
Fig. 2. The distribution of research objects based on life forms.

Fig. 3 .
Fig. 3.The distribution of research objects based on flowering periods.

Table 1 .
The number of rare plant species from the bioresearch collection of the Federal Research Center "Subtropical Scientific Center of the Russian Academy of Sciences" (FRC SSC RAS) with various conservation statuses.