Current State of Forest Moss Communities after Reduction of Emissions from the Middle-Ural Copper Smelter

The moss cover of forests in an 50×36 km area around the Middle-Ural Copper Smelter was analyzed after almost complete reduction of its emissions. It has been shown that the moss communities in the low and high pollution zones differ significantly in composition, number and frequency of species, but are characterized by a similar cover of ground mosses. The frequency of most species in the high pollution zones, compared to the low pollution zones, was decreased. A significant increase of the frequency in the pollution gradient was found for Pohlia nutans only. Species loss was expressed more strongly on the mesoscale (species richness within a community) than on the macroscale (the total number of species in a pollution zone). The elimination of species under increasing pollution was revealed for species with a low (up to 40%) initial frequency. Despite of the almost complete cessation of emissions from the smelter, the moss cover in the high pollution zones remains severely damaged and is formed by a single species (Pohlia nutans) over a significant area. However, localities with high species richness and high similarity of composition with the background communities occur even under high pollution conditions. The presence of such localities, in combination with a considerable time lag before the extinction of species from the study area as a whole, may have major significance for recolonization of degraded areas after emission reduction.

Epiphytic bryophytes of the State Dendrological Park “Olexandria” of the NAS of Ukraine

Investigations of the species diversity of epiphytic bryophytes of the State Dendrological Park “Olexandria” (the historical part and the “Budynok Lisnyka” plot) were conducted in 2017–2019 and revealed 40 species representing 22 genera, 17 families, seven orders, two classes, and two divisions. This corresponds to 46.51 % of the total number of detected bryophytes in the park. The leading families in the bryoflora of the park are Orthotrichaceae (9 species), Brachytheciaceae (6), Amblystegiaceae (3), Anomodontaceae (3), Dicranaceae (3), Hypnaceae (3), and Pottiaceae (2). The leading genera are Orthotrichum (9 species), Anomodon (3), and Dicranum (3).Among the identified taxa, five species (Dicranum tauricum, Orthotrichum lyellii, Porella platyphylla, Sciuro-hypnum reflexum, and Syntrichia virescens) are regionally rare within the Forest-Steppe zone of Ukraine. Most of the recorded epiphytic mosses were found on the bark of Acer platanoides (28 species), Fraxinus excelsior (27), Quercus robur (26), Acer campestre (23), and Tilia cordata (22). The least epiphytic mosses were found on the bark of conifers (Pinus sylvestris, P. strobus, Picea abies, Larix decidua, etc.).The surveyed trees in the State Dendrological Park “Olexandria” were also found such epigeal mosses as Plagiomnium cuspidatum, Ceratodon purpureus, Dicranella heteromalla, and Pohlia nutans, as well as epixilic moss Dicranum flagellare, etc.The “Budynok Lisnyka” plot hosts three species that do not occur in the park’s historical part. In particular, Lophocolea heterophylla and Sciuro-hypnum curtum were found there on Quercus robur trunks and Sciuro-hypnum reflexum on Quercus rubra bark. At the same time, the historical part of the park is characterized by the number of expansive bryophytes.

Identification, characterization and expression analysis of the chalcone synthase family in the Antarctic moss Pohlia nutans

Mosses have adapted to the Antarctic environment and are an ideal medium for studying plant resistance to abiotic stress. Chalcone synthase is the first committed enzyme in the flavonoid metabolic pathway, which plays an indispensable role in plant resistance to adversity. In this study, six genes (Pn021, PnCHS088, Pn270, PnCHS444, PnCHS768 and Pn847) were identified in the Antarctic moss Pohlia nutans Lindberg transcriptome by reverse transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). Sequence alignment and three-dimensional structure analysis revealed the conserved amino acid residues of the enzymes of the chalcone synthase family, including three catalytic residues (Cys164, His303 and Asn336) and two substrate recognition residues (Phe215 and Phe265). Phylogenetic analysis indicated that PnCHS088, PnCHS444 and PnCHS768 might be chalcone synthase but that Pn021 is more like stilbenecarboxylate synthase. These genes were located at the transition between fungi and advanced plants in the phylogenetic tree. In addition, real-time PCR analysis revealed that the expression profiles of the six P. nutans genes were influenced by diverse abiotic stresses as well as by abscisic acid and methyl jasmonate. The results presented here contribute to the study of the CHS gene family in polar mosses and further reveal the mechanisms underlying the adaptation of mosses to extreme environments.