Allium altaicum in the Altai Mountains: state of coenopopulations, reproductive potential, and prospects for introduction

Allium altaicum is a rare species native to the Altai Mountains, valued as a medicinal and vitamin-rich edible plant. It occurs across a wide range of altitudes, from the mountain-steppe zone to the alpine highlands (See Fig. 1). This article presents new data on the distribution and population status of this species in the Altai Mountains. The phytocoenotic associations, demographic characteristics of cenopopu-lations (CP), seasonal development patterns, morphology, and reproductive biology were studied. The main morphological and reproductive traits of A. altaicum in the wild were assessed and compared with those of cultivated specimens. The studied habitats are confined to steep, gravelly, and rocky slopes with high light exposure, where its abundance varies from sol (rare) to cop2 (common). On some shifting gravelly screes, A. altaicum is the absolute dominant plant. The vegetation cover of the studied communities involving A. altaicum is characterized by high species richness, ranging from 28 species (CP 1) to 50 species (CP 3). The demographic structure of A. altaicum cenopopulations is characterized by a predominance of individuals in the generative stage (gi-gs), whose accumulation is facilitated by an increased lifespan in this stage (63.2-89.1% of the total). The maximum peak in the age spectrum occurs among mature generative individuals. Cenopopulations exhibit a normal type, either full-fledged (senile individuals are not typical for this species) or incomplete (lacking juvenile individuals). According to the delta-omega classification, CP 1 is considered maturing, while CP 2 and CP 3 are mature (See Table 1). The largest number of generative shoots (on average 10.1 to 10.7 per individual) occurs in moving rubble screes (CP 1) or in weakly sodded areas with low grass cover (CP 2), where competition from other species in the phytocenosis is minimal (See Table 2). A comparison of the morphological characteristics of A. altaicum specimens from natural habitats with those grown under introduction experiments at the Siberian Botanical Garden of Tomsk State University (SibBS TSU) showed that cultivated specimens surpassed wild ones in some parameters. In its natural habitat, A. altaicum reproduces and spreads primarily by seed. Vegetative growth also occurs but does not contribute significantly to colonization of new territory. Although A. altaicum is characterized by high seed productivity, its propagation potential is far from fully realized under the harsh high-altitude conditions, as the processes of self-renewal by seed are significantly hindered. The lowest fruit set rate was observed in CP 1 (39.0%), where onion plants are frequently exposed to freezing temperatures during active growth and inflorescence formation. In contrast, onion plants growing in tall grass (CP 3) exhibited a significantly lower percentage of damaged flowers in the inflorescence, which was reflected in a higher fruit-to-flower ratio (62.5%) (See Table 3). Studies of the reproductive system of A. altaicum under introduction conditions have demonstrated significant differences among accessions in their primary reproductive traits. A. altaicum reproduces in cultivation both by seed and vegetatively, through the separation of bulblets formed on the rhizome. In the rare plant collection plots at SibBS TSU, the species is capable of self-seeding. However, specimens collected from CP 3 show limited bulblet formation on the rhizome and primarily reproduce by seed. In the wild, individuals from this cenopopulation produce no more than two bulblets per rhizome. Following a comprehensive introduction assessment, A. altaicum was classified as a resistant species. The gene pool of this rare and economically valuable plant, established at SibBS TSU, contributes to the successful ex situ conservation of the species and can be utilized to develop sustainable agropopulations and reintroduction programs aimed at restoring natural cenopopulations. The article contains 3 Figures, 3 Tables, 55 References. The Authors declare no conflict of interest.

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