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Currently, due to the increasing impact of anthropogenic factors and changes in solar activity, the temperature on Earth is rising, posing a threat to biodiversity. Lichens are among the most sensitive organisms to climate change. Elevated ambient temperatures can have a significant impact on lichens, resulting in more frequent and intense drying events that can impede metabolic activity. It has been suggested that the possession of a diverse sterol composition may contribute to the tolerance of lichens to adverse temperatures and other biotic and abiotic stresses. The major sterol found in lichens is ergosterol (ERG); however, the regulation of the ERG biosynthetic pathway, specifically the step of epoxidation of squalene to 2,3-oxidosqualene catalyzed by squalene epoxidase during stress, has not been extensively studied. In this study, we used lichen Lobaria pulmonaria as a model species that is well known to be sensitive to air pollution and habitat loss. Using in silico analysis, we identified cDNAs encoding squalene epoxidase from L. pulmonaria, designating them as LpSQE1 for the mycobiont and SrSQE1 for the photobiont Symbiochloris reticulata. Our results showed that compared with a control kept at room temperature (+20 °C), mild temperatures (+4 °C and +30 °C) did not affect the physiology of L. pulmonaria, assessed by changes in membrane integrity, respiration rates, and PSII activity. An extreme negative temperature (−20 °C) noticeably inhibited respiration but did not affect membrane stability. In contrast, treating lichen with a high positive temperature (+40 °C) significantly reduced all physiological parameters. Quantitative PCR analysis revealed that exposing thalli to −20 °C, +4 °C, +30 °C, and +40 °C stimulated the expression levels of LpSQE1 and SrSQE1 and led to a significant upregulation of Hsps. These data provide new information regarding the roles of sterols and Hsps in the response of lichens to climate change. [ABSTRACT FROM AUTHOR]

The effect of dust pollution on the photosynthesis and respiration parameters of foliose lichens Hypogimnia physodes (L.) Nyl, Lobaria pulmonaria (L.) Hoffm. and Peltigera aphthosa (L.) Willd., collected near the bauxite mine (Komi Republic, Russia) was investigated. Microscopic analysis showed that fine dust particles were mainly on the thalli surface, with a few mineral inclusions in the thalli medulla. The deposition of dust particles caused significant changes in the optical properties of the lichen surface in the visible and infrared spectral regions. A number of spectral indices (BRI, REP, RES, WI) sensitive to lichen pollution by dust emissions from the bauxite mine were identified due changes in the reflectance spectra of the thalli. Shading of the algal layer by mineral particles deposited on the thalli surface did not affect the content of photosynthetic pigments and PS II photochemical activity parameters. At the same time, lichen CO2-exchange parameters were observed to change. Lichen thalli from the polluted area were characterized by lower values of net CO2 uptake in the moderate light conditions (150 µmol PAR/m2 s), and the proportion of dark respiration in the gas exchange was 1.5 to 2 times higher than the values for thalli from background site. A 2-fold decrease in cytochrome respiration capacity was observed in thalli from the affected area. In thalli of L. pulmonaria and P. aphthosa, the energetically inefficient alternative respiratory pathway capacity increased 1.5‑fold and in H. physodes the activity of residual respiration increased more than 3.5-fold. The results obtained allowed an assessment of the chronic dust pollution effects on the foliose lichens symbionts functioning. The data may be useful for environmental biomonitoring. [ABSTRACT FROM AUTHOR]

Lobaria pulmonaria has been subject to strict and zonal protection in Poland for almost 20 years, assuming the function of an umbrella species for the protection of natural biodiversity. Knowledge about this function, however, is limited, mainly due to a lack of relevant research. The current protection zone with a radius (R) of up to 50 m was significantly reduced in 2014 compared to the previous one from 2004 (R=100 m), mainly due to the needs of forest management. This legislative change became why it was worth making a scientific balance of potential gains and losses. Corticolous lichens growing at circular sites with a radius of 150 m around lungwort host-trees, divided into three zones R=50 m, R=51-100 m, R=101-150 m, were selected as the biological group for verification. Beech ( Fagus sylvatica ) and sycamore ( Acer pseudoplatanus ) trees with DBH ≥40 cm, randomly located along the target azimuths of 0°, 120°, and 240°, were selected for the study at 15 sites located in the Polish Carpathians (Gorce and Bieszczady Mts). The research hypothesis was that the size of the L. pulmonaria protection zone in the Polish Carpathians is important for the conservation of a greater diversity of corticolous lichens. Based on the list of species, we assessed the statistical significance of differences in diversity indices between the zones and between the Gorce and Bieszczady sites, which was justified by the result of the DCA analysis. Both the total number of species and old-growth forest, legally protected and endangered species in Poland (categories EN, CR) were analyzed. Generally, the current protection zone with a radius of 50 m protects approx. 70% of all epiphytic lichen diversity and the same share of other investigated groups, while increasing the protection zone to R=100 m saves almost 90% of species representing these groups of lichens.

Cyanolichens are symbiotic organisms involving cyanobacteria and fungi (bipartite) or with the addition of an algal partner (tripartite). Cyanolichens are known for their heightened susceptibility to environmental pollution. We focus here on the impacts on cyanolichens due to rising air pollution; we are especially interested in the role of sulfur dioxide on cyanolichen biology. Cyanolichens due to air pollution including sulfur dioxide exposure, show symptomatic changes including degradation of chlorophyll, lipid membrane peroxidation, decrease in ATP production, changes in respiration rate, and alteration of endogenous auxins and ethylene production, although symptoms are known to vary with species and genotype. Sulfur dioxide has been shown to be damaging to photosynthesis but is relatively benign on nitrogen fixation which proposes as a hypothesis that the algal partner may be more in harm's way than the cyanobiont. In fact, the Nostoc cyanobiont of sulfur dioxide-susceptible Lobaria pulmonaria carries a magnified set of sulfur (alkane sulfonate) metabolism genes capable of alkane sulfonate transport and assimilation, which were only unraveled by genome sequencing, a technology unavailable in the 1950–2000 epoch, where most physiology- based studies were performed. There is worldwide a growing corpus of evidence that sulfur has an important role to play in biological symbioses including rhizobia-legumes, mycorrhizae-roots and cyanobacteria-host plants. Furthermore, the fungal and algal partners of L. pulmonaria appear not to have the sulfonate transporter genes again providing the roles of ambient-sulfur (alkanesulfonate metabolism etc.) mediated functions primarily to the cyanobacterial partner. In conclusion, we have addressed here the role of the atmospheric pollutant sulfur dioxide to tripartite cyanolichen viability and suggest that the weaker link is likely to be the photosynthetic algal (chlorophyte) partner and not the nitrogen-fixing cyanobiont. [ABSTRACT FROM AUTHOR]

It is well-known that the switch of an organism ontogenetic state is accompanied with the change in metabolic status, especially, the activity of antioxidant system enzymes. However, there is still lack of knowledge about the internal changes which occur during the shift between ontogenetic stages in lichens. In this study, superoxide dismutase (SOD) and catalase (CAT) activities were measured for Lobaria pulmonaria thalli from middle boreal subzone on the Karelian Republic territory. We have shown that the transition between ontogenetic stages in L. pulmonaria could be observed not only by the set of morphological features, but also by changes in the activity of SOD and CAT for the first time. Therefore, we have made a conclusion that the enzyme activity could be the basis for more justified separation of different ontogenetic stages and identifying processes associated with aging. [ABSTRACT FROM AUTHOR]

Lichenized fungi as a multicomponent biological system are an interesting but difficult research object. In view of the complex interaction of the myco- and photobiont, the slow growth of natural thalli, their exceptional exactingness to environmental factors, the study of the biological characteristics of lichens is significantly difficult. This article discusses the problem of studying the anatomical and morphological structure of the myco- and photobiont of lichenized fungi using the tissue culture method on the example of rare species (Lobaria pulmonaria) and species with pharmaceutical potential (Usnea dasopoga, Cetraria islandica). The authors proposed a method for cultivating of myco- and photobionts of these species on synthetic nutrient media for the purpose of further research on the characteristics of lichenized fungi. Fragments of thalli, apothecia (for C. islandica), and soredia (for U. dasopoga and L. pulmonaria) were used as donor material. For the introduction of the photobiont under sterile conditions, a homogenate of the thallus region was prepared. Pure cultures of the myco- and photobiont of L. pulmonaria, U. dasopoga, and C. islandica were obtained on three types of hormone-free nutrient media, namely MS nutrient medium, modified MS medium with a reduced nitrogen content, Czapek medium. The verification of the research results was carried out taking into account the microscopy of the obtained cultures of myco- and photobionts. Using microscopy, the dimensional characteristics of the obtained mycobionts were determined. The diameters of the hyphae of L. pulmonaria, U. dasopoga, and C. islandica were 4.3–4.4 µm, 4.6 µm, and 4.1–4.3 µm, respectively, which corresponds to the size of the hyphae in natural samples. The use of the tissue culture method makes it possible to study and analyze the biological characteristics of lichenized fungi as a multicomponent biological system, as well as to contribute to the preservation of rare species and their components in the Red Data Book; while optimizing the method of cultivating myco- and photobiont on synthetic nutrient media, to reduce the anthropogenic load on natural populations of lichens when using them as medicinal raw materials.

Lichens are unique phototrophic organisms whose physiology of stress tolerance attracts much attention. Parameters of photosynthetic and respiratory activities of the epiphytic large-leaved lichen Lobaria pulmonaria were investigated with an aim to reveal physiological responses to seasonal changes in environmental conditions. The highest accumulation of chlorophylls in thalli (2.3 mg/g dry wt) was noted in autumn (October); the amount of green pigments decreased 2.5 times in spring (April). The chlorophyll/carotenoid ratio varied from 3.1 to 4.4. The extent of deepoxidation of xanthophyll cycle pigments equaled 34% in winter but it was two times as low in summer. When L. pulmonaria thalli were hydrated and acclimated shortly under standard laboratory conditions, they exhibited a relatively high photochemical activity and were able to assimilate CO2 throughout the entire annual cycle. The rate of net CO2 uptake by thalli under optimal irradiance and temperature ranged from 3 to 5 µmol CO2/m2 s and the highest values were recorded in spring. No significant seasonal changes were observed in the total respiration rate of thalli. The proportions of various respiratory pathways were altered in spring and autumn, and metabolic heat production was accelerated due to the activation of an energetically low-efficient alternative respiratory pathway. The results provide evidence that the functional adaptation of photo- and mycobionts in the lichen is implicated in resistance of this complete system to seasonal changes in environmental conditions. [ABSTRACT FROM AUTHOR]

Forest management practices may heavily affect epiphytic cryptogams. This study was conceived in March 2016, as soon as we were informed about an authorized logging for timber within a Mediterranean mixed oak forest in Tuscany (central Italy), which threatened a large population of the forest macrolichen Lobaria pulmonaria (L.) Hoffm., composed of hundreds of fertile thalli. Lobaria pulmonaria is often used as an ecological indicator of high quality habitats hosting rare lichens, and in general, cryptogams worthy of conservation. The species has suffered a general decline throughout Europe as a consequence of air pollution and intensive forest management, and currently it is red-listed in several countries, where it is considered also as a “flag species”. We estimated that 40% of the lichen biomass (8.5-12.3 kg ha-1) has been lost due to logging operations (in the core area, up to 1.8 kg every 100 m2), in particular large and fertile thalli. One year after the conclusion of logging operations, the analysis of chlorophyll fluorescence emission (indicator of the photosynthetic performance of the lichen photobionts), revealed a significant reduction of the vitality of the thalli on retained-isolated trees. The article provides issues for conservation in Mediterranean oak forests and outlines the outmost importance of ensuring the safeguard of forest ecosystems hosting fertile populations of this model species, especially in the case of unprotected forests.

Forest management practices may heavily impact epiphytic (tree inhabiting) organisms. Retaining tree patches and buffer strips in logged stands may contribute to preserve ecosystem functioning and the vitality of epiphytic organisms in managed forests. To test these statements, the threatened forest macrolichen Lobaria pulmonaria (L.) Hoffm. was used as a model species, since it is a “flag” indicator species of forest ecosystems with long ecological continuity. To this purpose, photosynthetic performances, thallus anatomy and water holding capacity (WHC) of samples of L. pulmonaria were investigated in a logged mixed oak forest (Tuscany, Italy), confronting lichen thalli from retained-forest patches and retained-isolated trees, 18 months after logging. Compared with those of retained-forest patches, thalli on the trunks of retained-isolated trees were thinner and showed lower vitality (as indicated by the potential quantum yield of primary photochemistry - FV/FM and the index of overall photosynthetic performance - PIABS), as well as lower water holding capacity. In contrast, thalli from forest patches had performances comparable to those of healthy samples from unlogged forests.

Lichens represent self-supporting symbioses, which occur in a wide range of terrestrial habitats and which contribute significantly to mineral cycling and energy flow at a global scale. Lichens usually grow much slower than higher plants. Nevertheless, lichens can contribute substantially to biomass production. This review focuses on the lichen symbiosis in general and especially on the model species Lobaria pulmonaria L. Hoffm., which is a large foliose lichen that occurs worldwide on tree trunks in undisturbed forests with long ecological continuity. In comparison to many other lichens, L. pulmonaria is less tolerant to desiccation and highly sensitive to air pollution. The name-giving mycobiont (belonging to the Ascomycota), provides a protective layer covering a layer of the green-algal photobiont (Dictyochloropsis reticulata) and interspersed cyanobacterial cell clusters (Nostoc spec.). Recently performed metaproteome analyses confirm the partition of functions in lichen partnerships. The ample functional diversity of the mycobiont contrasts the predominant function of the photobiont in production (and secretion) of energy-rich carbohydrates, and the cyanobiont’s contribution by nitrogen fixation. In addition, high throughput and state-of-the-art metagenomics and community fingerprinting, metatranscriptomics, and MS-based metaproteomics identify the bacterial community present on L. pulmonaria as a surprisingly abundant and structurally integrated element of the lichen symbiosis. Comparative metaproteome analyses of lichens from different sampling sites suggest the presence of a relatively stable core microbiome and a sampling site-specific portion of the microbiome. Moreover, these studies indicate how the microbiota may contribute to the symbiotic system, to improve its health, growth and fitness.

Lichens represent self-supporting symbioses, which occur in a wide range of terrestrial habitats and which contribute significantly to mineral cycling and energy flow at a global scale. Lichens usually grow much slower than higher plants. Nevertheless, lichens can contribute substantially to biomass production. This review focuses on the lichen symbiosis in general and especially on the model species Lobaria pulmonaria L. Hoffm., which is a large foliose lichen that occurs worldwide on tree trunks in undisturbed forests with long ecological continuity. In comparison to many other lichens, L. pulmonaria is less tolerant to desiccation and highly sensitive to air pollution. The name-giving mycobiont (belonging to the Ascomycota), provides a protective layer covering a layer of the green-algal photobiont (Dictyochloropsis reticulata) and interspersed cyanobacterial cell clusters (Nostoc spec.). Recently performed metaproteome analyses confirm the partition of functions in lichen partnerships. The ample functional diversity of the mycobiont contrasts the predominant function of the photobiont in production (and secretion) of energy-rich carbohydrates, and the cyanobiont's contribution by nitrogen fixation. In addition, high throughput and state-of-the-art metagenomics and community fingerprinting, metatranscriptomics, and MS-based metaproteomics identify the bacterial community present on L. pulmonaria as a surprisingly abundant and structurally integrated element of the lichen symbiosis. Comparative metaproteome analyses of lichens from different sampling sites suggest the presence of a relatively stable core microbiome and a sampling site-specific portion of the microbiome. Moreover, these studies indicate how the microbiota may contribute to the symbiotic system, to improve its health, growth and fitness. [ABSTRACT FROM AUTHOR]

Peter D. Crittenden served as senior editor of The Lichenologist, the flagship journal in the field of lichenological research, for a period of two decades, between 2000 and 2019. A review of the development of the journal and the publication output during this period is provided. The number of papers published during this period (1197) matches that of all papers published under the three previous senior editors, Peter W. James, David L. Hawksworth and Dennis H. Brown, during a much longer period of 42 years from 1958 to 1999. Peter oversaw important editorial changes to the layout and content of the journal: an increased size with a modern cover design, leaving behind the classic mint-coloured cover of more than 40 years; the addition of 'thematic issues' and encouragement of large monographs; implementation of substantial changes to the Code, such as effective electronic publication and obligate registration of new fungal names; and more recently a new policy to reject so-called 'single naked species descriptions'. Shortly before Peter took over as senior editor, The Lichenologist had received its first impact factor, and Peter managed to continuously increase this measure from around 0.9 to lately up to over 1.5, higher than most other competing journals. The 1197 papers between 2000 and 2019 were published by a total of 1138 different authors, more than half of whom appeared just once as author, whereas a small number participated in numerous (up to 93) papers. There was a continuous increase in the mean number of authors per paper per year, from below 2.5 to around 3.5, the highest numbers ranging between 11 and 30; still, c. 75% of all papers between 2000 and 2019 were single-authored or had up to three authors. Based on affiliations at the time of publication, two thirds of author contributions came from Europe (66%), 13% from North America, 9% from Asia and 7% from Latin America. Likewise, almost half of the study areas were located in Europe and around 10% each in North America, South America and Asia. The countries with the highest number of studies included, in descending order, the United States, Spain, the United Kingdom, Norway and Sweden. North America and Europe were over-represented in terms of author contributions, whereas Africa, Latin America, Australia and Oceania were over-represented in terms of study areas. The 1197 papers analyzed encompassed a broad diversity of topics, classified into 32 categories. Taxonomy of lichenized fungi was the most frequent component, representing the focal point in almost half of all studies, followed by phylogeny and evolution, ecology, and the taxonomy of lichenicolous fungi. Around two thirds of the currently accepted genera of lichenized fungi were treated, with a significant correlation between known species richness and the number of papers in which a genus was treated, underlining the taxonomic representativity of papers published in the journal during the past two decades. Examples of genera that were treated more frequently than expected included commonly studied model organisms, such as Lobaria, and those frequently featured in ecological or other non-taxonomic studies, such as Xanthoria. Species-rich tropical genera, particularly in the Graphidaceae, were generally under-represented. Mean number of authors per paper per volume and total number of country origins of authors per volume were the best predictors of impact factor, followed by diversity of study countries per volume, mean number of study countries per paper per volume, mean number of topics per paper per volume, and proportion of studies with phylogenetic components per volume. Individual papers that contributed to high impact factors included broad-scale revisionary treatments and worldwide keys to species-rich taxa, substantial phylogenetic reclassifications of known taxonomic groups, papers dealing with novel methodological approaches of broad interest, and broad-scale studies related to environmental change and lichen biomonitoring. [ABSTRACT FROM AUTHOR]

This paper is a continuation of the new series started in 2020 to publish the new or interesting lichenological discoveries made in Switzerland or in the Geneva canton. Lobaria pulmonaria, a macrolichen endangered in a large part of its distribution area in Europe and particularly on the Swiss plain, was rediscovered in the canton of Geneva. Rhizoplaca subdiscrepans a distinct species from R. chrysoleuca was found to occur in three localities in Switzerland. [ABSTRACT FROM AUTHOR]

A lichen diversity survey of White Pine Hollow State Preserve in Dubuque County, Iowa, revealed the presence of 117 different lichens including 13 previously unrecorded for the state of Iowa, 72 previously unrecorded for Dubuque County, and one recorded in Iowa on only one prior occasion. This increases the number of lichens reported for the state of Iowa to a total of 478 and the number recorded for White Pine Hollow to 123. Lobaria pulmonaria (L.) Hoffm., an old-growth specialist that is facing declines around the globe, was not amongst the lichens observed although one of the last known collections (1901) of this lichen in Iowa occurred at White Pine Hollow. Efforts to propagate L. pulmonaria in a greenhouse setting as a means of providing insight to whether a reintroduction might be feasible were unsuccessful. [ABSTRACT FROM AUTHOR]

The paper describes the ontogenesis of the epiphytic lichen Lobaria pulmonaria. The studies were carried out in the Karelian forest communities with the period since the last disturbance ranging from 80 to 450 years. Based on the concept of a discrete description of plants and lichens, four periods and 14 age-related states have been distinguished in L. pulmonaria's ontogenesis. Each ontogenetic state of L. pulmonaria is characterized by a certain thallus size as well as by the presence and the level of development of vegetative diaspores and apothecia on the thallus surface. The possible variants of the species ontogenesis are described. [ABSTRACT FROM AUTHOR]

Lichens associated with old forest are commonly assumed to be negatively affected by tree logging or natural disturbances. However, in this study performed in a spruce-dominated sylvopastoral landscape in the Swiss Jura Mountains, we found that genetic diversity of the epiphytic old-forest lichen Lobaria pulmonaria depends on the type of disturbance. We collected 923 thalli from 41 sampling plots of 1 ha corresponding to the categories stand-replacing disturbance (burnt), intensive logging (logged) and uneven-aged forestry (uneven-aged), and analysed the thalli at six mycobiont-specific microsatellite loci. We found evidence for multiple independent immigrations into demes located in burnt and logged areas. Using spatial autocorrelation methods, the spatial scale of the genetic structure caused by the clonal and recombinant component of genetic variation was determined. Spatial autocorrelation of genotype diversity was strong at short distances up to 50 m in logged demes, up to 100 m in uneven-aged demes, with the strongest autocorrelation up to 150 m for burnt demes. The spatial autocorrelation was predominantly attributed to clonal dispersal of vegetative propagules. After accounting for the clonal component, we did not find significant spatial autocorrelation in gene diversity. This pattern may indicate low dispersal ranges of clonal propagules, but random dispersal of sexual ascospores. Genetic diversity was highest in logged demes, and lowest in burnt demes. Our results suggest that genetic diversity of epiphytic lichen demes may not necessarily be impacted by stand-level disturbances for extended time periods.

Abstract Background Recent evidence of specific bacterial communities extended the traditional concept of fungal-algal lichen symbioses by a further organismal kingdom. Although functional roles were already assigned to dominant members of the highly diversified microbiota, a substantial fraction of the ubiquitous colonizers remained unexplored. We employed a multi-omics approach to further characterize functional guilds in an unconventional model system. Results The general community structure of the lichen-associated microbiota was shown to be highly similar irrespective of the employed omics approach. Five highly abundant bacterial orders—Sphingomonadales, Rhodospirillales, Myxococcales, Chthoniobacterales, and Sphingobacteriales—harbor functions that are of substantial importance for the holobiome. Identified functions range from the provision of vitamins and cofactors to the degradation of phenolic compounds like phenylpropanoid, xylenols, and cresols. Conclusions Functions that facilitate the persistence of Lobaria pulmonaria under unfavorable conditions were present in previously overlooked fractions of the microbiota. So far, unrecognized groups like Chthoniobacterales (Verrucomicrobia) emerged as functional protectors in the lichen microbiome. By combining multi-omics and imaging techniques, we highlight previously overlooked participants in the complex microenvironment of the lichens.

Frontenac Provincial Park is located on the Frontenac Axis, a southern extension of the Canadian Shield, linking Algonquin Park to the Adirondack Mountains. To better understand the lichen biota of this interesting ecosystem, an inventory was conducted during several field visits from 2016–2019. During these surveys, 280 species of lichens and allied fungi in 115 genera were discovered. Presented is the first published record of Lempholemma cladodes (Tuck.) Zahlbr. in Canada, as well as the first published discoveries of Cladonia petrophila R. C. Harris, Coccocarpia palmicola (Spreng.) Arv. & D. J. Galloway, and Leprocaulon adhaerens (K. Knudsen, Elix & Lendemer) Lendemer & B. P. Hodk. in Ontario. Sixteen species are provincially ranked as critically imperilled (S1, S1S2 or S1S3), sixteen species as imperilled (S2 or S2S3), and nineteen species as vulnerable (S3 or S3S4). Unranked species reported for the second time in Canada are Dermatocarpon muhlenbergii (Ach.) Müll. Arg. and Cladonia atlantica A. Evans. An undescribed species of Lempholemma growing on flooded deciduous tree bases in vernal pools was also discovered. A discussion of Lobaria pulmonaria (L.) Hoffm., a pollution and habitat disturbance sensitive species, is presented. The records of L. pulmonaria discovered in Frontenac quite possibly represent the most southern observations in the province and are of conservation concern. It is recommended that a lichen awareness and education program be created for the park staff and visitors to highlight these rare and sensitive lichens and habitats within the park in the hope that lichens are protected through appropriate management and planning. [ABSTRACT FROM AUTHOR]

The present study was carried out to evaluate the activity of antioxidant enzymes and the protein content in Lobaria pulmonaria thalli of various ontogenetic stages (studied groups: juvenile and mature) in forest communities of the middle and northernmost boreal subzones (i.e. two habitat groups). Obtained results showed that the protein content in thalli of different ontogenetic stages and habitats did not differ significantly between the two studied groups and ranged from 3.4 to 3.8 mg g-1. Peroxidase (POD) activity was low and did not exceed 0.01 µmol TG mg-1 of protein. No significant differences between the studied groups (ontogenetic and habitat) in POD was found. On the contrary, the activity of superoxide dismutase (SOD) and catalase (CAT) showed significant differences. SOD activity ranged from 5.1 to 6.3 U mg-1 of protein. Significant differences were found between the SOD activity in juvenile and mature L. pulmonaria thalli in the communities of the northern boreal subzone (p = 0.043) and in juvenile thalli from different habitats (p = 0.020). In general, CAT activity ranged from 187 to 605 μmol H2O2 mg-1 protein. Significant differences in CAT activity were apparent between the thalli from the middle and northernmost boreal subzone communities (p=0.040). The differences in CAT activity values in juvenile and mature thalli in the northernmost boreal subzone (p = 0.006) were found as well. Juvenile thalli from different habitats (p = 0.008) differed. As a result we suggest that juvenile thalli might be more suitable for the purposes of bioindication of environmental conditions, such as temperature, humidity, since they are more sensitive in comparison to mature thalli. [ABSTRACT FROM AUTHOR]

The research is devoted to the investigation of chemical composition of epiphytic lichens Lobaria pulmonaria growing in the territory of the Barguzin Nature Reserve in the Republic of Buryatia (Russia). This reserve is considered as a background area because of its far location from anthropogenic pollution sources. The objective of this research is to assess the chemical composition of lichens of the Barguzin Nature Reserve – one of the background areas in Russia. 9 lichen samples were collected in the summer 2015, in which the concentrations of 67 chemical elements were detected using inductively coupled plasma mass-spectrometry. The research findings were compared with the data for the lichens from the Zabaykalsky National Park and taiga forest in Tomsk region (oil field area). Comparing the reserve area with the taiga area (with anthropogenic load from oil field development), it was detected that the lichens from the Barguzin Nature Reserve had lower concentrations of most chemical elements except Na, Mg, Al, Si, P, K, Ca, and Ti, which contents are 2-16-fold higher in the lichens of the Barguzin Reserve. The concentrations of most chemical elements detected in the lichen samples of the Barguzin Nature Reserve can be used as baseline values while investigating territories with different anthropogenic load.

Sacred Natural Sites are relevant for biodiversity conservation, as in the case of forest sites that, across centuries, developed old growth structures and are now crucial for the conservation of epiphytic lichens and other specialized forest organisms. In this study, we investigated the epiphytic lichen flora of a small forest patch included in the Majella National Park (Abruzzo), whose old growth features and naturalness reflect its long lasting spiritual role that perfectly fits with the concept of Sacred Natural Site. Results revealed that the "Bosco di Sant'Antonio" hosts a rich and interesting epiphytic lichen flora, thus indicating the potential of this Sacred Natural Site for lichen conservation. Fifty-six species were found including two species newly recorded in Abruzzo, two red-listed species, and the sensitive species Lobaria pulmonaria. This study corroborates the hypothesis that sacred forest sites are relevant for the conservation of specialized epiphytic lichens. In particular, in the Italian forest landscape where old-growth stands are practically absent, sacred forest sites may provide unique old-growth structures and buffer anthropogenic disturbance. [ABSTRACT FROM AUTHOR]

Abstract We studied the potential to use reintroduction of two declining N-fixing flagship lichens to identify factors affecting failure or success in SW Swedish sites that had experienced substantially reduced acidification. After transplanting the critically endangered Lobaria amplissima ± external cephalodia and its near-threatened associate Lobaria pulmonaria onto tree trunks, seasonal growth rates were quantified. We added a phosphorus treatment, using site as a random factor. Growth was positive in winter, and negative in summer, particularly in L. amplissima. Reintroduction of L. amplissima was unsuccessful because gastropods caused significant loss, evidenced by grazing marks. Acer platanoides , a high-pH host, had more grazing than the more acidic Quercus petraea. Gastropods preferred the cephalodia, resulting in substantial loss of the cephalodiate L. amplissima. Phosphorus fertilization had no effects. The widespread L. pulmonaria grew faster than the rare L. amplissima that lost its local growth potential due to aggravated gastropod grazing. Highlights • Growth rates of reintroduced lichens were positive in winter, negative in summer. • Gastropod grazing was much higher in Lobaria amplissima than in Lobaria pulmonaria. • Gastropods grazed more on lichens transplanted to Acer than to Quercus in summer. • One P-fertilization dose did not influence growth rate or grazing. • Reintroduction of Lobaria amplissa to sites in SW Sweden was unsuccessful. [ABSTRACT FROM AUTHOR]

Quantitative parameters of cenopopulations of Lobaria pulmonaria, an endangered cyanolichen, have been studied in spruce phytocenoses of Karelia recovering after disturbance through the successional stage of aspen stands for a period ranging from 80 to 450 years. The results show that, as the time since disturbance increases, the total number of L. pulmonaria thalli and the number of colonized substrate units increase as well, with no stabilization of these parameters being observed in the series of communities studied. The total area of thalli in the phytocenoses is restored within approximately 200 years after the last disturbance. In old-growth forests (>400 years), L. pulmonaria thalli colonize a broad spectrum of tree species in different life states, including lower branches of young spruce trees. Even if they serve as temporary substrates, this can markedly strengthen the potential of the species for further expansion within the community in case of shortage in the main phorophyte (aspen). Thus, the proportion of regressive populations decreases, while that of colonizing populations increases, which is indicative of successful reproduction of the species. [ABSTRACT FROM AUTHOR]

Lichens are considered freezing tolerant, although few species have been tested. Growth, a robust measure of fitness integrating processes in all partners of a lichen thallus, has not yet been used as a viability measure after freezing. We compared relative growth rates (RGR) after freezing with short-term viability measures of photo- and mycobiont functions in the coastal Lobaria virens and the widespread L. pulmonaria to test the hypothesis that low temperature shapes the coastal distribution of L. virens . Hydrated thalli from sympatric populations were subjected to freezing at −10, −20 and −40 °C for 5 h. The rate of cooling and subsequent warming was 5 °C h −1 . Short-term viability measures of photobiont (maximal photosystem II efficiency, effective PSII yield) and mycobiont viability (conductivity index), as well as subsequent RGR, were assessed. The exotherms showed that L. virens froze at −3 °C; L. pulmonaria, at −4 °C. Freezing significantly impaired short-term viability measures of both photo- and mycobiont, particularly in the coastal species. Lobaria pulmonaria grew 2.1 times faster than L. virens , but the short-term damage after one freezing event did not affect the long-term RGR in any species. Thereby, short-term responses were impaired by freezing, long-term responses were not. While the lacking RGR-responses to freezing suggest that freezing tolerance does not shape the coastal distribution of L. virens , the significant reported adverse short-term effects in L. virens may be aggravated by repeated freezing-thawing cycles in cold winters. In such a perspective, repeated freezing may eventually lead to reduced long-term fitness in L. virens . [ABSTRACT FROM AUTHOR]

The research is devoted to the investigation of chemical composition of epiphytic lichens Lobaria pulmonaria growing in the territory of the Barguzin Nature Reserve in the Republic of Buryatia (Russia). This reserve is considered as a background area because of its far location from anthropogenic pollution sources. The objective of this research is to assess the chemical composition of lichens of the Barguzin Nature Reserve - one of the background areas in Russia. 9 lichen samples were collected in the summer 2015, in which the concentrations of 67 chemical elements were detected using inductively coupled plasma mass-spectrometry. The research findings were compared with the data for the lichens from the Zabaykalsky National Park and taiga forest in Tomsk region (oil field area). Comparing the reserve area with the taiga area (with anthropogenic load from oil field development), it was detected that the lichens from the Barguzin Nature Reserve had lower concentrations of most chemical elements except Na, Mg, Al, Si, P, K, Ca, and Ti, which contents are 2-16-fold higher in the lichens of the Barguzin Reserve. The concentrations of most chemical elements detected in the lichen samples of the Barguzin Nature Reserve can be used as baseline values while investigating territories with different anthropogenic load. [ABSTRACT FROM AUTHOR]

Chlorophyll a fluorescence is often used to estimate various types of damage in lichens. In order to optimize the output and improve interpretations of such measurements the protocol for pretreatment and measuring is important. To study the effects of measurement conditions, the lichens Lobaria pulmonaria, L. scrobiculata, Xanthoria parietina and Parmelia sulcata were first stressed by high light intensities at 600 or 1000 µmol photons m−2 s−1 for 4 h. Then various conditions during recovery or pretreatment were used to optimize the detection of more lasting damage. Recovery from photoinhibition was incomplete in darkness, whereas light as low as 0·2 or 1·0 µmol m−2 s−1 resulted in complete recovery if the recovery period was long enough. Additionally, low intensity light given for1·5 h after one day in darkness caused rapid and complete recovery. In conclusion, before measuring maximal PSII efficiency (Fv/Fm) with chlorophyll fluorescence, it is important to let lichens recover in low intensity light and not in darkness, to optimize recovery from photoinhibition; dark adaptation can only be recommended if the photoinhibition status of the lichens is of interest. [ABSTRACT FROM AUTHOR]

The old forest lichen Lobaria pulmonaria synthesizes melanic pigments when exposed to ultraviolet light and high solar radiation. Here, we tested the effect of melanisation on photosynthetic efficiency. Melanisation effectively reduces high-light stress in lichen photobionts, as the photobionts of melanised thalli are healthy, based on chlorophyll contents and maximum rates of photosynthesis. However, the quantum yields of both photosynthetic CO 2 uptake and O 2 evolution were more than 40 percent lower in melanised thalli compared with control thalli. While chlorophyll fluorescence measurements suggested that melanised and pale thalli had similar apparent electron transport rates, this result was probably an artefact caused by screening reducing the light reaching the photobionts. Melanic thalli also had a higher chlorophyll a/b ratio and more xanthophyll cycle pigments, suggesting that the photosynthetic apparatus had adapted to high light. In conclusion, while protecting photobionts from high light, melanisation clearly reduced photosynthetic efficiency. Melanised thalli will be significantly disadvantaged if light levels return to lower values, more typical for those habitats in which this shade adapted lichen is most abundant. [ABSTRACT FROM AUTHOR]

This study aims to quantify the size-dependency of important hydration traits in Lobaria amplissima, L. pulmonaria and L. virens sampled in sympatric populations on deciduous tree trunks in southern Norway, and to discuss possible implications of species-specific traits for the ecological niches of these old forest cephalolichens. Traits measured were thallus size (area and mass), specific thallus mass (STM), internal (WHCinternal) and external water-holding capacity (WHCexternal), and water content (WC) after shaking and after blotting. Lobaria amplissima had the highest WHCinternal, 2·6 times higher than L. pulmonaria with the lowest WHCinternal. WHCinternal, driven by STM, strongly depended on size. WHCexternal was 28% (L. virens) to 47% (L. pulmonaria) of the WHCinternal. Unlike WHCinternal, WHCexternal did not depend on thallus area, meaning that WHCexternal is proportionally higher for smaller compared with larger thalli. The most widespread species, L. pulmonaria, benefits from a flexible hydration strategy due to low STM, facilitating the use of more diverse water sources than the other two species that depend more on rain, particularly L. amplissima with the highest STM and thus relatively high WHCinternal. For L. virens, a combination of less specialized hydration traits and a low tolerance to higher light intensity probably jeopardizes its survival outside rainforest habitats. [ABSTRACT FROM AUTHOR]

By fluorescence imaging, we quantified how hydration traits and thallus size determine the duration of photosynthetic activity during drying in light and darkness for sympatric populations of three epiphytic old forest cephalolichens differing in specific thallus mass (STM) and growth form. Maximal PS II efficiency ( F V /F M ) during drying in darkness and effective PSII yield ( Ф PSII ) during drying in light (200 μmol m −2 s −1 ) was repeatedly monitored in lichens under controlled conditions, using chlorophyll fluorescence imaging with simultaneous recordings of wet mass. STM shaping the water holding capacity (WHC), water content in percent at start (WC), and water loss rate per thallus area (WLR) in combination determined the duration of active periods during desiccation between ( r 2 ad j = 0.86) and within species ( r 2 adj = 0.60–0.92). Lobaria pulmonaria with the lowest STM and the most upright growth form experienced the shortest active periods, Lobaria amplissima with the highest STM and the most prostrate growth form had the longest periods. Across the more compact species ( L. amplissima, L. virens ), WLR strongly declined with increasing thallus size, but weakly in the loosely attached L. pulmonaria . Ф PSII , a proxy of photosynthesis, exhibited suprasaturation depression at maximal hydration. Fluorescence imaging allowed a rapid, non-invasive evaluation of the contribution of various functional traits to active periods in entire thalli during desiccation. A thick, prostrate growth form prolongs active periods by maximizing water storage, whereas a thin, loosely attached growth form uses a more flexible hydration strategy with shorter active periods. [ABSTRACT FROM AUTHOR]

We quantified relative growth rates (RGR) in shade-adapted and melanin-deficient thalli of Cetraria islandica and Lobaria pulmonaria cultivated in short-term growth chamber experiments with and without UV-B radiation. In the first experiment done under optimal PAR (125 μmol m s), but high UV-B radiation (1 W m), UV-B radiation significantly reduced RGR ( P < 0.001). The second experiment with higher PAR, but more natural ratios between wavelength ranges (PAR: 500 μmol m s; UV-A: 7 W m; UV-B: 0.4 W m), caused a reduction in mean RGR in L. pulmonaria to just 45% of rates in experiment 1. Lobaria pulmonaria screened from UV-B radiation had 1.9 and 1.6 times higher RGR than non-screened thalli in experiment 1 and 2, respectively. UV-B radiation significantly induced melanin synthesis in the second experiment only, causing significantly less photoinhibition than in thalli receiving just PAR. This is consistent with PAR-protective roles of melanins. Chlorophylls were not affected by UV-B radiation in any experiment. Because UV-B radiation affected RGR more than pure photobiont responses, the mycobiont is likely the more UV-B-susceptible partner. Apart from reduced RGR, we found little evidence for adverse UV-B effects. [ABSTRACT FROM AUTHOR]

To test the hypotheses that (1) protective mycobiont tissues and/or (2) medullary UV-B-absorbing carbon-based secondary compounds (CBSCs) protect lichen photobionts against UV-B radiation, we quantified cortical UV-transmittance and ran a three-way factorial lab experiment with (1) three UV radiation regimes, (2) photobiont layers with/without a screening cortex, and (3) with natural/reduced CBSC-concentration. We used melanin-deficient Lobaria pulmonaria from shaded forests. Maximum photochemical efficiency of photosystem II ( F v/ F m) in photobionts inside thalli with natural CBSC-concentrations was not affected by any UV-regime, consistent with close to 0% measured cortical transmittance of wavelengths <325 nm. Exposing photobiont layers to direct radiation strongly aggravated photoinhibition ( P < 0.001), as did an increase in UV-exposure ( P < 0.001). The effect of CBSC-removal was weaker (yet significant at P = 0.001), mainly affecting exposed photobiont layers given short-wavelength UV radiation. Based on these findings, we conclude that the primary role of extrolites in L. pulmonaria is not to screen excess solar radiation. [ABSTRACT FROM AUTHOR]

The growth inhibition of stictic acid, a secondary metabolite isolated from the lichen Lobaria pulmonaria (L.) Hoffm. (Lobariaceae), was evaluated in vitro on three human cell lines for the first time. The cell lines HT-29 and MCF-7 were utilized for measuring the activity of stictic acid against cancer cells, while the cell line MRC-5 was selected for estimation of its effect on normal cells. The results suggest a moderate anticancer activity (IC50 value for the cell line HT-29 was 29.29 μg/ml) and a low growth inhibition on nonmalignant cells (IC50 value for the cell line MRC-5 was 2478.40 μg/ml) of stictic acid. This natural product can be considered as a promising lead compound for the design of novel human colon adenocarcinoma drugs.

The population structure of the lichen Lobaria pulmonaria (L.) Hoffm. was analyzed in the Vodlozersky National Park (Karelia, Russia), for middle boreal forest stands having a time-since-disturbance spanning 80 to 450 years. To estimate the age of the last disturbance, a method of evaluation for the tree population structure was applied. The forest stand communities belonged to a successional series: middle-aged aspen - mixed aspen-spruce - pre-climax spruce - climax (old-growth) spruce forest. All thalli (1055) of L. pulmonaria from all substrate units (165, separately standing or lying trees and shrubs) were described within 7 sample plots of 1 ha. For each thallus, the area (cm²) and the functional-age group were determined. The number of Lobaria thalli per ha, number of substrate units, number of substrate types (living, standing dead and lying dead trees of different species) colonized by L. pulmonaria, as well as number of substrate types on which the lichen had completed its life cycle increased with time-since-disturbance. [ABSTRACT FROM AUTHOR]

Self-sustaining lichen symbioses potentially can become very old, sometimes even thousands of years in nature. In the joint structures, algal partners are sheltered between fungal structures that are externally colonized by bacterial communities. With this arrangement lichens survive long periods of drought, and lichen thalli can be revitalized even after decades of dry storage in a herbarium. To study the effects of long-term ex situ storage on viability of indigenous bacterial communities we comparatively studied herbarium-stored material of the lung lichen, Lobaria pulmonaria. We discovered that a significant fraction of the lichen-associated bacterial community survives herbarium storage of nearly 80 years, and living bacteria can still be found in even older material. As the bacteria reside in the upper surface layers of the lichen material, we argue that the extracellular polysaccharides of lichens contribute to superior life expectancy of bacteria. Deeper understanding of underlying mechanisms could provide novel possibilities for biotechnological applications. [ABSTRACT FROM AUTHOR]

In order to improve growth chamber protocols for lichens, we tested the effect of 1) wet filter paper versus self-drained nets as a substratum for lichens, and 2) gradual versus abrupt transitions between dark and light periods. For Lobaria pulmonaria (L.) Hoffm. cultivated on nets, RGR increased by 60% compared to those on wet papers, whereas abrupt on/off transitions between day/night gave as high growth rates as gradual transitions mimicking sunrise/sunset. Because thalli on nets had less surface water than those on papers, the higher RGR on nets likely resulted from less suprasaturation depression of photosynthesis. By supporting very high growth and eliminating any visible damage, the revised growth chamber protocols facilitate new functional lichen studies. [ABSTRACT FROM PUBLISHER]

Rhizobiales (Alphaproteobacteria) are well-known beneficial partners in plant-microbe interactions. Less is known about the occurrence and function of Rhizobiales in the lichen symbiosis, although it has previously been shown that Alphaproteobacteria are the dominating group in growing lichen thalli. We have analyzed the taxonomic structure and assigned functions to Rhizobiales within a metagenomic dataset of the lung lichen Lobaria pulmonaria L. One third (32.2%) of the overall bacteria belong to the Rhizobiales, in particular to the families Methylobacteriaceae, Bradyrhizobiaceae and Rhizobiaceae. About 20% of our metagenomic assignments could not be placed in any of the Rhizobiales lineages, which indicates a yet undescribed bacterial diversity. SEED-based functional analysis focused on Rhizobiales and revealed functions supporting the symbiosis, including auxin and vitamin production, nitrogen fixation and stress protection. We also have used a specifically developed probe to localize Rhizobiales by confocal laser scanning microscopy after fluorescence in situ hybridization (FISH-CLSM). Bacteria preferentially colonized fungal surfaces, but there is clear evidence that members of the Rhizobiales are able to intrude at varying depths into the interhyphal gelatinous matrix of the upper lichen cortical layer and that at least occasionally some bacteria also are capable to colonize the interior of the fungal hyphae. Interestingly, the gradual development of an endosymbiotic bacterial life was found for lichen- as well as for plant-associated bacteria. The new tools to study Rhizobiales applied in this study, FISH microscopy and comparative metagenomics will help to better understand the beneficial roles for their hosts and their biotechnological potential.