Ecological and biological features of Polygala sibirica from the southern part of Western Siberia

The paper reports data on the distribution and status of coenopopulations of the rare and valuable medicinal plant P. sibirica from the southern part of Western Siberia. The study investigated the phytocoenotic confinement, demographic characteristics of coenopopulations, seasonal patterns of growth, morphology, and reproductive biology. In mountainous areas, the species permanently inhabits rocky mountain steppes. In the plain of Western Siberia, its localities are fragmentary. P. sibirica coenopopulations are characterized by low density, ranging from 1.83 to 4.57 ind./m2. The ontogenetic structure of coenopopulations shows a predominance of generative individuals (53.6–76.9%). The ontogenetic spectrum of coenopopulations is characterized as incomplete, unimodal (CP 1–3, CP 5, CP 7–9) or bimodal (CP 4 and CP 6), with a predominance of generative individuals and a low proportion of old age groups. The analysis of the morphological characteristics of P. sibirica indicates that the largest plants with long, branched shoots and large leaves and inflorescences are found at the range boundary. Coenopopulations differ significantly in LMA, leaf chlorophyll content and nitrogen status values. It is shown that vegetation indices CCI, CRI1, VREI1 and ZMI can be used to assess the physiological status of plants under different ecological and coenotic conditions. P. sibirica reproduces exclusively by seed. Most flowers develop into mature fruits (FFR = 77.1–93.5%). Real seed productivity varies considerably, ranging from 10.8 to 77.8 seeds per shoot. Most of the studied coenopopulations exhibit the above-average level of reproductive potential (Cp = 65.2–77.9%). Under anthropogenic pressure, P. sibirica coenopopulations retain self-sustaining ability and can survive for extended periods within the range.