The study of specific chromosome
numbers allows assessing the taxonomic diversity of flora, revealing the
centers of its origin, tracking their respective migration paths and forecasting
the behavior of species under man-made environmental changes. A comprehensive
taxonomic and karyofloristic analysis of these data allows to keep species
in view in the context of their phylogenetic associations and evolution,
their respective ranges, specific habitat conditions and changes therein.
A karyologic study of the flora of the southern part of the Russian Far East presents special interest, since, in addition to being abundant and diverse, it is characterized by a large number of plant species not represented in other regions of Russia.
A.P. Sokolovskaya, a botanist and cytologist from Leningrad and her students, who first initiated karyologic studies of Primorye’s unique flora, began karyologic studies of the vascular flora of Primorye in 1962. Today the Laboratory of Higher Plants, Institute of Biology and Soil Science, Far East Branch, Russian Academy of Sciences, and other researchers are continuing this work. Thanks to all of them, the karyology of Primorye’s flora is now one of the best studied in the Russian Far East. Today, the number of vascular plant species in Primorye with estimated chromosome numbers already exceeds 1,060, which is close to 50% of the specific composition of local flora.
Evidence on chromosome numbers of Primorye flora species is mostly scattered in numerous publications. At present, the Laboratory for Higher Plants, supported by Russia’s Federal Fund for Promotion of Basic Research, is actively preparing to publish the first compendium of documented data on chromosome numbers of Primorye’s vascular flora. The data were collected over the entire period of its study till the very latest determinations continually made by the researchers involved.
The authors use the analysis of species chromosome numbers in connection with specific taxonomy, endemism, and ecogeographic differentiation to probe into problems of florogenesis, plant protection and monitoring. One of the areas of application of obtained data involves a more differentiated approach to protection of biologic diversity with account for the karyotaxonomic situation in a given taxonomic group, to which the vulnerable species belongs. The study of the karyotaxonomic situation in groups of endemic, rare and relict species and taxa on the range boundary allows forecasting their correlation to man-made factors. This primarily concerns rare and “Red Book” species, and also those entering Russia only in Primorye: for numerous species of these groups, original figures are available for chromosome numbers obtained in Primorye.
The Sea of Japan forms a major part of Primorye’s territory. We especially distinguish the basin of Suifun (Razdolnaya) River due to its international significance, and the basin of Rudnaya River as an area of industrial pollution, as well as the islands of Peter the Great Bay and, finally, the continental coastal areas of Primorye (the remaining part of the Japan Sea basin). In addition, we distinguish the Amur River basin, subdivided into the basin of Lake Hanka proper and the basin of Ussuri River. Again, we distinguish the Sikhote Alin mountain range as a separate entity.
The first publication by N. S. Probatova and A. P. Sokolovskaya on the caryology of flora from the islands of Peter the Great Bay was prepared in connection with the start of karyological studies of flora on the islands of the Far East National Marine Sanctuary. In their joint monograph titled “ Vascular Plants from Islands of Peter the Great Bay, Primorye, Sea of Japan” (Daljnauka, in press), Probatova, Seledets, Nedoluzhko and Pavlova cite the chromosome numbers for 204 vascular plant species scrutinized on those islands from 148 genera and 56 families; this amounts to about 20% of the specific composition of the island flora. The study of insular flora is continuing, and today we already know the chromosome numbers for 250 species. The specificity of the insular flora of Peter the Great Bay involves abundance of diploid species and a low percentage of high-level polyploids; cases of intraspecific karyologic polymorphism are relatively rare. East Asian forest species form the main core of the island flora, and among them over half are ancient species, diploids. Seacoast (chiefly North Pacific) species with likewise prevalent low-polypoid (2x, 4x) taxa are second in significance. This could be indicative of the relative antiquity of this group.
The flora of Suifun and Rudnaya River basins was not specially studied caryologically, but according to our estimates the chromosome number in Suifun River has at this point been determined in over 150 species, and over 50 species have been investigated in the Rudnaya River basin.
In the continental coastal part of Japan Sea (including above-mentioned river basins), chromosome numbers were studied in almost 400 species. The karyology of the coastal sea flora of the Russian Far East (including that of Japan Sea coasts) was specially examined in a work by N. S. Probatova, V.P. Seledets and A. P. Sokolovskaya (1984) titled “Halophylic plants of the seacoasts of the Soviet Far East: chromosome numbers and ecology”. The study of seacoast plant species in Primorye is continuing.
In recent years, the water and coastal flora of Japan Sea has become a subject of special study due to its considerable diversity in the region, the relict nature of its numerous representatives in Primorye’s flora, the presence of many rare highly-specialized species, and the endangered status of their populations resulting from man-made changes in the landscape. A study of chromosome numbers and ploidy levels in the species of this group could allow for a novel approach in estimating the biological potential of these species and the priority of protection.
An attempt is being made to show the role of hybridization
N. PROBATOVA, Institute of
Biology and Soil Science, F. E. Branch, Russian Academy of Sciences