Sexual differetiation of Rhodiola rosea L. populations in the high-mountain zone of the Ukrainian Carpathians

Background. Individual (morphological) and group parameters (the number of male and female individuals, their sex ratio, and the range of sex ratio displacement) are an important indicator of sexual differentiation of Rhodiola rosea L. populations. To date, indicators of these parameters in natural plant populations have not been studied sufficiently. Therefore, for the analysis of the state of the populations of the species, it is important to study the parameters of their sexual differentiation and the main trends of changes that affect the ability to recover in high-mountain conditions. Methods. In order to obtain data, conventional stationary and route-based research methods were used. To record individuals of different sexes, long-term monitoring plots were used, which were laid in the characteristic habitats of the species’ populations in 2000–2022. The ratio of male and female individuals is determined based on their quantitative distribution per unit area. The sexual potential index that determines the proportion of females and their participation in generative reproduction was used. Results. The main differences in the morphological and quantitative parameters of male and female individuals in high-mountain conditions were determined. It was found that a characteristic feature during long-term research is a decrease in the number of generative individuals of both male and female sexes. In the studied populations, there is a shift in the sex ratio towards males (73 %) and this trend has been maintained over the last dozen of years. Therefore, the number of females compared to males is very small, which affects the sexual potential of populations. Conclusions. The ratio of male and female individuals, the range of its displacement and potential participation in the realization of sexual potential in R. rosea was determined. The present study showed that the general trend in the populations of the species is a decrease in the number of female individuals. Male biased sex ratio has an impact on sexual potential and ability to generative reproduction.