Anatomical Features of the Leaves of Honckenya peploides and Cochlearia officinalis in the Supralittoral and Littoral Zones of the Barents Sea

The environmental adaptations of plants to the conditions of the supralittoral and littoral of the Barents Sea coast are examined, and a comprehensive study of the anatomical features of the leaf blades of Honckenya peploides (L.) and Cochlearia officinalis (L.) is carried out. The study uses plants collected in the budding phase. The leaves are fixed in 70% ethanol. The elements of the anatomical structure are measured using a light microscope. It is established that the environmental conditions of the coastal zone determine the formation of specific anatomical features in these plants. H. peploides is characterized as a more highly specialized species with pronounced xeromorphic features: amphistomatic leaves, a developed cuticle layer, and an isolateral mesophyll structure. C. officinalis is a heterogeneous species. In supralittoral conditions, it exhibits mesomorphic features such as sinuous cell walls, hypostomatic leaves, and the clear differentiation of the mesophyll into columnar and spongy layers, as well as the presence of large intercellular cells in the spongy mesophyll. On the upper littoral, C. officinalis acquires xeromorphic features: an increase in the thickness of the leaf and cuticle, as well as amphistomaticity. The combination of meso- and xeromorphic features probably favors the distribution of C. officinalis in a wider range of the coastal zone. The data confirm the close connection of the anatomical structure of the leaves with environmental conditions and reflect the specific adaptations of each species to the environment.