Abstract
Abstract Rosa dsharkenti Chrshan. is a narrowly distributed endemic shrub of south-eastern Kazakhstan occurring in riparian and above-floodplain terrace habitats exposed to pronounced differences in soil conditions. This study investigated three natural populations of the species in the Usek River corridor to evaluate the relationships between soil properties and morpho-anatomical traits. Soil sampling included 21 horizon samples collected from the three populations, and laboratory analyses covered pH, SOM, total nitrogen, soluble salts, soil moisture and particle-size composition. Anatomical analyses of roots, stems and leaves were performed using light microscopy and morphometric measurements. All studied soils were strongly alkaline, with pH ranging from 8.73 to 9.83, but the populations differed markedly in surface-horizon moisture, humus content, salinity and fine-particle content. Population P1 was associated with higher surface moisture and stronger development of epidermal and supportive tissues, P2 with greater leaf thickness, larger vascular bundle diameter and a strongly developed primary cortex, and P3 with a sandy surface horizon and stronger development of photosynthetic leaf tissues together with thicker secondary phloem. Non-parametric tests revealed significant inter-population differences in several leaf and stem traits. Pearson correlation analysis and principal component analysis further indicated that anatomical variation was associated with differences in soil moisture, texture, alkalinity and nutrient status. The results indicate that R. dsharkenti exhibits considerable population-level structural variation linked to local edaphic conditions, highlighting the importance of conservation of different habitat types and the selection of locally appropriate plant material for restoration and ecological engineering within the native range of this endemic species. Conservation should therefore retain both riparian and terrace habitats within the Usek River corridor.