The Role of Secondary Metabolites and Bark Chemistry in Shaping Diversity and Abundance of Epiphytic Lichens

Diversity of secondary lichen metabolites was studied in epiphytic lichens on six phorophytes—spruce, pine, birch, alder, aspen and poplar in the Middle Urals of Russia. Atranorin, usnic, fumarprotocetraric acid, zeorin, and gyrophoric acid were found in 31, 24, 23, 18, and 14 species, respectively, of 237 taxa collected. Seventy-seven species (i.e., 32% of total species documented) contained no secondary metabolites. Spectra of secondary metabolites of fruticose and foliose lichens varied on different phorophytes, while in crustose species the strong dependence on the tree species was not detected. This is different to the pH dependence of saxicolous lichens where crustose lichens were more susceptible to the rock chemistry. The results of Canonical Correspondence Analysis reveal the affinity of species containing depsides, depsidones or usnic acid to acidic substrata and those lacking secondary metabolites or containing terpenes and antraquinones to the pH-neutral bark. We suppose that phenolic compounds and flavonoids, as chemical constituents of bark, may interact with lichen symbioses and elements in phellem, and similarly to the lichen acids shape the affinity of species to the substrata. Copyright © 2022 Paukov, Teptina, Ermoshin, Kruglova and Shabardina.Russian Science Foundation, RSF: 22-24-00817AE was partially supported by the Russian Science Foundation, grant number 22-24-00817

Simulation of the processes of plasma modification and vacuum metallization of polymer materials by the method of molecular dynamics

The article presents the results of the development of molecular dynamics models of modifications of polypropylene (PP) material in the plasma of a radio-frequency (RF) discharge and a copper coating deposit by magnetron sputtering on the surface of a polyethylene (PE) material. The model of the RF plasma modification process describes changes in the surface layers of the PP material upon interaction with low-energy plasma ions: the nature of the breaking of covalent bonds in macromolecules, the chemical composition of sputtered particles, and changes in the ordering of the supramolecular structure. The model of the vacuum metallization process describes the processes of the introduction of metal atoms into the polymer structure, the change in the conformation of macromolecules, the formation of macroradicals with uncompensated chemical bonds, and the formation of an interfacial layer between the polymer and the metal coating

Ultramafic vegetation and soils in the circumboreal region of the Northern Hemisphere

The paper summarizes literature on climate, soil chemistry, vegetation and metal accumulation by plants found on ultramafic substrata in the circumboreal zone (sensu Takhtajan, Floristic regions of the world, 1986) of the Northern Hemisphere. We present a list of 50 endemic species and 18 ecotypes obligate to ultramafic soils from the circumboreal region of Holarctic, as well as 30 and 2 species of Ni and Zn hyperaccumulators, respectively. The number of both endemics and hyperaccumulators are markedly lower compared to that of the Mediterranean and tropical regions. The diversity of plant communities on ultramafics soils of the circumboral region is also described. The underlying causes for the differences of ultramafic flora between arctic, cold, cool temperate and Mediterranean and tropical regions are also discussed. © 2018, The Ecological Society of Japan

PETROPHITIC-STEPPOUS FLORA OF THE KYSHTYM MOUNTAIN URALS, HISTORY OF STUDY AND MODERN STATE

Study of the unique petrophytic-steppous flora of the Kyshtym mountain Urals, which has a long history of botanical investigations, has been surveyed. Contribution to the study of flora was introduced by famous botanists P. N. Krylov, V. B. Sochava, P. L. Gorchakovsky and others. Modern state of the odds raises serious concerns. Thus, the petrophytic-steppous flora on the Karabash mountain, which has been under intense aerotechnogenic impact for more than 100 years, has been almost completely lost. A number of species previously mentioned for other mountains may also have been lost. In the course of this paper, a comparative analysis of the floristic diversity of three different petrophytic-steppous communities that are part of the Kyshtym mountain Urals was conducted. The flora includes 122 species from 31 families. In general, steppous species predominate. 6 Ural endemic species were found.Работа выполнена при поддержке гранта РФФИ № 16–04–01346а

Simulation of the processes of plasma modification and vacuum metallization of polymer materials by the method of molecular dynamics

The article presents the results of the development of molecular dynamics models of modifications of polypropylene (PP) material in the plasma of a radio-frequency (RF) discharge and a copper coating deposit by magnetron sputtering on the surface of a polyethylene (PE) material. The model of the RF plasma modification process describes changes in the surface layers of the PP material upon interaction with low-energy plasma ions: the nature of the breaking of covalent bonds in macromolecules, the chemical composition of sputtered particles, and changes in the ordering of the supramolecular structure. The model of the vacuum metallization process describes the processes of the introduction of metal atoms into the polymer structure, the change in the conformation of macromolecules, the formation of macroradicals with uncompensated chemical bonds, and the formation of an interfacial layer between the polymer and the metal coating

PETROPHYTIC STEPPES OF URAL: DIVERSITY AND ECOLOGICAL DRIVERS

Estimation of coenotic diversity of Ural petrophytic steppes and determination main ecological drivers of its differentiation were carried out. The dataset includes 1025 releves, plots are located in different climatic and geological conditions. All relevés were classified using the TWINSPAN algorithm in JUICE 7.0 (Tichy, 2002) and 8 groups of communities were allocated. According to DCA-ordination importance of a number of ecological gardients both climatic and edaphic were detrmined. High level of floristic diversity and influence of ecological gradients are considered as the main drivers of petrophytic steppes diversity in the Urals.Работа выполнена при поддержке РФФИ (проект № № 17–04–00276а)