Evaluation of the Ecological and Genetic Potential of Megadenia bardunovii Popov. (Brassicaceae) in the Tunkinsky National Park (Southern Siberia)

Rare endemic plant species are most sensitive to changes in ecosystems, which can negatively affect the state of their populations. The study of various ecological parameters in natural locations is most important for their monitoring and conservation. Megadenia bardunovii is a relict species of Tertiary vegetation with a limited range. In Russia, two small populations are known in the Tunka Valley (Republic of Buryatia). In this research, we have studied the composition of water and soil in the natural location of the species, the area of its populations, and its phylogenetic relationships, carried out an introduction experiment, and estimated the seed reproduction. The confinement of populations to freshwater springs and loose, fertile sod-carbonate soils has been revealed. It has been shown that the populations occupy an area of 408 and 564 m2. Seed germination is low; vegetative reproduction predominates. Analysis of nuclear (ITS) and chloroplast (rbcL, matK, trnL-trnF, and trnH-psbA) markers has revealed the absence of genetic diversity in the two studied populations. Analysis of chloroplast DNA has shown that the populations from the Tunka Valley represent a separate evolutionary lineage, significantly different from all other Megadenia populations in China and the Russian Far East. The introduction experiment has shown that an adult individual is a perennial creeping-root polycarpic plant and consists of a set of rosette shoots formed from adventitious buds on plagiotropic roots. In the introduction experiment, the morphometric parameters of plants were close to those in situ. Under culture conditions, the species is moderately promising for introduction and moderately resistant during long-term cultivation; it does not withstand competition from other species. The biological features determine the species strategy: rapid occupation of a territory using adventitious buds on the roots. The studied populations can be characterized as relatively stable under existing conditions. It is relevant to develop and maintain of a reserve fund. The results supplement the data on the ecology and biology of the species and determine the parameters for monitoring and preserving the species in its natural habitats.