山西省太岳山区有害元素大气污染的地衣(丽石黄衣)监测

山西太岳山区大气元素沉降研究较少。为摸清该区域大气污染水平及其受盆地的可能影响,以ICP-MS法测定采自15个样点的丽石黄衣(Xanthoria elegans)地衣体内7种常见有害元素(As、Cd、Cu、Pb、S、Sb和Zn)的含量,并进行相关性分析、方差分析和聚类分析。结果显示:该区域元素含量一般高于"清洁区",但低于"严重污染区"的相应数据,表明太岳山区具有一定程度的大气污染。聚类分析将15个样点分为两类,两类样点在距盆地距离(distance from the nearest basin, DFNB)和多数元素的含量方面均差异显著,近盆地区(DFNB=13.7±7.987 km)中的6种元素(As、Cd、Cu、Pb、Sb和Zn)含量均显著高于远盆地区(DFNB=32.5±6.062 km), 5种元素(As、Cu、Pb、Sb和Zn)的含量与DFNB之间的负相关关系显著(r≤-0.59; P≤0.02),表明山区内部的大气质量受盆地地区的大气污染物传输的影响。S含量的空间异质性低(变异系数CV10%),和DFNB的相关性及在近盆地区和远盆地区之间的差异均不显著(P0.05),但仍随DFNB增加呈下降趋势,表明盆地人类活动所释放的S可能主要是以更易于扩散的气态形式向山区传输的。本研究结果表明丽石黄衣是太岳山区大气有害元素污染的良好监测生物。     

Synthesis and Antioxidant Evaluation of O-Methylated Emodacidamides: Starting from Parietin,a Secondary Metabolite of Lichen Xanthoria parietina

Polyhydroxy-anthraquinones bearing amino acids are found rather seldom in nature. Emodacidamides, isolated from a marine-derived fungus, Penicillium sp. SCSIO sof101 by Luo et al. (2017) are the first natural example of amino acid conjugated anthraquinone. In this study, O-methylated emodacidamides and emodinic acid-anilides were synthesized starting from parietin, extracted from the lichen Xanthoria parietina (L.) Th. Fr. The structural elucidations of prepared compounds were confirmed by 1D and 2D NMR analyses including HSQC and HMBC techniques. In addition, all newly synthesized compounds were evaluated for the antioxidant activities with free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging. The synthesized compounds showed low to moderate antioxidant and DPPH scavenging activities. The antioxidant activities were supported within quantum chemical calculations using the DFT−B3LYP/6-311++G(d,p) level of theory. It is observed that the antioxidant activity of emodacidamides mostly depends on the phenolic groups on anthraquinone ring. The phenolic groups on other substituents help to improve antioxidant activity and also the position of hydroxy group is a decisive factor for antioxidant ability.     

Parietin,a photoprotective secondary product of the lichen Xanthoria parietina

Secondary lichen products can be extracted from air-dry thalli of Xanthoria parietina, Xanthoparmelia conspersa and Parmelina tiliacea with 100% acetone without affecting either short-or long-term viability. In Xanthoria parientina damage by acetone started to occur as water content reached the critical lower limit for photosystem II (PSII) activity. Extraction of the blue-light absorbing cortical pigment parietin increased the susceptibility of both air-dry and hydrated thalli to high light. Damage by high light levels caused a permanent reduction in F _v/F_m, quantum yield for photosynthetic O₂ production and photosynthetic capacity measured after a 2-day recovery period at low light levels (20 mol photons m^-2 s^-1). Parietin therefore protects the photosynthetic apparatus of Xanthoria parietina against damage by high light levels. Extraction of UV-absorbing pigments from Xanthoparmelia conspersa and Parmelina tiliacea did not increase photoinhibition after 24 h exposure to high light.     

Photosynthates stimulate the UV-B induced fungal anthraquinone synthesis in the foliose lichen Xanthoria parietina

Synthesis of the cortical anthraquinone pigment parietin (= physcion) was studied in acetone‐rinsed, parietin‐free Xanthoria parietina thalli. UV‐B induced the synthesis, which increased linearly with UV‐B (log‐transformed) to the highest applied UV‐B level (1.8 W m^?2). At natural UV‐B levels (0.75 W m^?2), parietin resynthesis occurred at a constant pace (106 mg m^?2 d^?1) during a 14‐d period at 220 µmol m^?2 s^?1 PAR. Under these conditions, 56% of the natural parietin content prior to extraction was resumed, accounting for 10% of total net carbon gain. In the presence of UV‐B, the remaining results were consistent with the hypothesis assuming that photosynthates regulate the pace at which parietin is synthesized by the mycobiont. Resynthesis was rapid when photosynthesis was activated by light, or when certain carbohydrates were added exogenously. Additions of ribitol, the carbohydrate delivered from the photobiont, increased the parietin resynthesis substantially. Mannitol, the main fungal polyol, was significantly less effective. Furthermore, parietin resynthesis in X. parietina was depressed at high and low hydration when net photosynthesis is depressed. Therefore, the photobiont regulates the parietin resynthesis pace in its mycobiont partner by the delivery of photosynthates. In conclusion, both lichen bionts play important roles in the synthesis of parietin, which probably acts as a PAR‐ rather than a UV‐B‐screen.     

Correlationships between Enzymatic Activity of Lectins, Putrescine Content and Chloroplast Damage in Xanthoria parietina Phycobionts

Lectins from the lichen Xanthoria parietina develop arginase activity. One of these lectins behaves as a secreted arginase whereas another is an endocellular enzyme. Both enzymes are glycosylated proteins differing in the occurrence of galactose instead of N-acetyl-D-glucosamine in secreted arginase. The affinity for the algal ligand (glycosylated cell wall urease) of secreted arginase is higher than that shown for the endocellular enzyme. When the lectin ligand is absent from the algal cell wall, both endocellular and secreted arginases seem to be able to enter algal cells. This uptake promotes the increase in the amount of algal putrescine, preferently as free polyamine, and the chloroplast is rapidly damaged. Induction of cell wall urease retains lectins outside the cells, on the cell wall, and chloroplast remains healthy.     

Field Studies on Growth and Regenerative Capacity in the Foliose Macrolichen Xanthoria parietina (Teloschistales,Ascomycotina)

Growth and development of the foliose macrolichen Xanthoria parietina and adjacent lichen and bryophyte spp. was photographically monitored over a period of five years. This association developed on a plane quadrangle on the top surface of a sandstone block in the botanical garden of the University of Zürich. Line tracings of the thalline outlines were used for a quantitative estimation of laminal growth by means of gravimetric morphometry. Average radial growth of approximately 6 mm yr^?1 was recorded, with maxima around 7 mm yr^?1. The oldest, apothecia-covered central parts of the thalli lost contact with the substratum and broke off along stress cracks but the blank substratum was rapidly re-colonized by new thallus lobes which regenerated along the wound margins, to our present knowledge a peculiarity of X. parietina and few related species among the Teloschistales. Approximately 50% of the surface area of the experimental plot was covered by X. parietina at the beginning and again at the end of this five years period, with significant fluctuations in the time between. New growth in the range of 87% of the total surface area almost compensated the losses of approximately 90% per surface area in five years. New growth and losses within these five years accounted for more than 170% of the initial coverage. X. parietina gains a significant ecological advantage from its very remarkable regenerative capacity.     

Genetic variation and population differentiation in the lichen-forming ascomycete Xanthoria parietina on the island Storfosna, central Norway

Genetic diversity and fine-scale population structure in the lichen-forming ascomycete Xanthoria parietina was investigated using sequence variation in part of the intergenic spacer (IGS) and the complete internal transcribed spacer (ITS) regions of the nuclear ribosomal DNA. Sampling included 213 and 225 individuals, respectively, from seven populations in two different habitats, bark and rock, on the island Storfosna off the central west coast of Norway. Both markers revealed significant variation and a total of 10 IGS and 16 ITS haplotypes were found. There were no signs of significant positive spatial autocorrelation at any spatial size class down to 10% of transect length, nor did we find significant deviations from neutrality or signs of historical population expansion. Analysis of molecular variance (amova) indicated that most of the genetic variance observed was within populations, but when populations were grouped according to habitat, more than a quarter of the variance was explained among groups. Pairwise comparisons of populations (F(ST), exact tests of population differentiation) revealed significant differentiation between populations in different habitats (on bark or rock), but not between populations in the same habitat. Haplotype networks show that internal and presumably old haplotypes are shared between habitats, whereas terminal haplotypes tend to be unique to a habitat, mostly bark. We interpret the observed pattern to mean that there is no evidence of restricted gene flow between populations in the same habitat at the present spatial scale (interpopulation distances one or a few kilometres). On the other hand, differentiation between habitats is considerable, which we attribute to restricted gene flow between habitats (habitat isolation). Evidence suggests that the observed differentiation did not evolve locally. Estimates of divergence time between populations in the respective habitats indicate that an ancestral population started to diverge at least 34,000 years ago but probably much further back in time.     

The effect of different night conditions on the CO2 fixation in a lichen Xanthoria parietina

CO₂ fixation was studied in a lichen, Xanthoria parietina, kept in continuous light, and with cyclic changes in light intensity, dark period or temperature. The diurnal and seasonal courses of CO₂ exchange were followed. The rate of net photosynthesis was observed to fall from morning to evening, and this decline was more pronounced in winter than in summer. The maximal net photosynthetic rate, 223 ng CO₂g^-1dws^-1, occured in winter and the minimum, 94 ng CO₂g^-1dws^-1, late in spring. The light compensation point in summer was four times as high as in winter. In continuous light (180 or 90 mol photons m^-2s^-1, 15°C) net photosynthesis decreased noticeably during one week, falling below the level maintained in a 12 h light: 12 h dark cycle. Photosynthetic activity did not decrease, however, in lichens held in continuous light (90 mol photons m^-2s^-1) with cyclic changes of temperature (12 h 20 °C: 12 h 5 °C). Active photosynthesis was also maintained in light of cyclically changing intensity (12 h: 12 h, 15 °C) when night-time light was at least 75% lower than illumination by day. A dark period of 4 hours in a 24-h light:dark cycle was sufficient to keep CO₂ fixation at the control level. It seems that plants need an unproductive period during the day to survive and this can be induced by fluctuations in light and/or temperature.     

Interfacial self-assembly of fungal hydrophobins of the lichen-forming ascomycetes Xanthoria parietina and X. ectaneoides

In the symbiotic phenotype of the lichen-forming ascomycetes Xanthoria parietina and X. ectaneoides, a conglutinate, hydrophilic cortex surrounds a system of aerial hyphae with hydrophobic wall surfaces. In X. parietina freeze-fracture electron microscopy showed that a rodlet layer covers the fungal and algal wall surfaces. Extracts of hot SDS-insoluble wall residues isolated from both species contained a protein that revealed a rodlet layer upon interfacial self-assembly. The N-terminal sequence of the 10-kDa protein of X. ectaneoides served to clone cDNA fragments of XEH1 (H1 of X. ectaneoides) and XPH1 (H1 of X. parietina) by RT-PCR. Genomic DNA blot analysis with both lichenized species and the aposymbiotically cultured symbionts of X. parietina showed that XPH1 and XEH1 are fungal single copy genes. The deduced amino acid sequences of the two encoded proteins were 96% identical and showed the characteristics of class I hydrophobins.     

Biomonitoring of heavy metals by epiphytic lichen species in Black Sea region of Turkey

The heavy metal accumulation in epiphytic lichens along the Sarp-Samsun Highway in Black Sea Region of Turkey was analyzed by using energy dispersive X-ray fluorescence (EDXRF) and flame atomic absorption spectroscopy (FAAS) methods. The analysis showed that the lichen samples contained elevated concentrations of the following metals: titanium, chromium, manganese, iron, cobalt, nickel, copper, zinc, tin, barium, and lead. A strong positive correlation was observed between the lead concentration of the lichens and the traffic density.     

Faecal pellets of lichenivorous mites contain viable cells of the lichen-forming ascomycete Xanthoria parietina and its green algal photobiont, Trebouxia arboricola

The bright yellow wall lichen, Xanthoria parietina , is usually inhabited by oribatid mites (Acari) which do not only find shelter, but also graze on selected areas of the thallus. As X. parietina does not produce symbiotic vegetative propagules and its compatible photobiont, unicellular green algae of the genus Trebouxia , are rare outside lichen thalli, we tested the hypothesis of dispersal of viable Trebouxia cells via acarine faeces. The lichenivorous mites, Trhypochtonius tectorum and Trichoribates trimaculatus , were isolated from thalli of X. parietina and cultured in the laboratory on a lichen diet. Light microscopic investigations of faecal pellets from mites that had been feeding on X. parietina indicated gut passage of intact ascospores and photobiont cells. In a series of experiments, viable algal and fungal cells contained in such faecal pellets were cultured. The taxonomic affiliation of these isolates was identified using molecular techniques, i.e. comparative investigations of nuclear ribosomal gene data (ITS 1 and 2, 5.8S rDNA) in the algal and fungal partners, and of the species-specific hydrophobin gene sequence in the fungal partner. Our culturing experiments demonstrated that the faecal pellets of both lichenivorous mites, upon feeding on X. parietina , contain viable ascospores and photobiont cells ( Trebouxia arboricola ) and thus might be a common and successful mode of vegetative short- and long-distance dispersal of this and numerous other lichen-forming ascomycetes and their photobionts. Future studies will have to elucidate the evolutionary significance of invertebrate interactions with lichens. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 76 , 259–268.     

藓袋法对深圳市痕量大气重金属污染物的监测

通过在深圳市盐田、罗湖、福田、南山4个行政区17个不同地点布放藓袋,并对其所吸附的 V、Cr、Mn、Co、Ni、Cu、Zn、As、Cd、Pb 等10种重金属元素的含量进行检测和比较研究,发现4个行政区在不同程度上都受到了污染,其中南山区的污染较轻,罗湖区、福田区与盐田区较为严重。污染程度可能与水陆交通和工业状况、人口密度以及特殊的地理位置有关。对深圳市17个监测点的大气重金属富集含量进行聚类分析发现,污染较为严重的地区均为工业区和交通密集区,污染相对较轻的监测点都离工业及交通污染源相对较远。     

Analysis of airborne pollen fall in Sakarya, Turkey

In this study, pollen grains were identified using Durham sampler in the atmosphere of Sakarya in 2000 and 2001. During these two years, a total of 10 805 pollen grains were recorded. A total of 5 386 pollen grains per cm² were recorded in 2000 and a total of 5 419 pollen grains per cm² in 2001. Pollen fall in the years 2000–2001 comprised grains belonging to 40 taxa and some unidentified pollen grains. Of these taxa, 22 belonged to arboreal and 18 taxa to non arboreal plants. Total pollen grains consisted of 69.45% grains from arboreal plants, 28.11% grains from non-arboreal plants and 2.44% unidentified pollen grains. In the region investigated, Gramineae, Pinus sp., Quercus sp., Cupressaceae/Taxaceae, Salix sp., Platanus sp., Populus sp., Carpinus sp., Fagus sp., Chenopodiaceae/Amaranthaceae, Xanthium sp., Moraceae, Corylus sp., Fraxinus sp., and Urticaceae released the greatest amount of pollen. The season of maximum pollen fall was from March to May, with a prevalence of arboreal pollen in the first months, and of pollen from non-arboreal plants in the last months of the year.     

Parietin in the tolerant lichen Xanthoria parietina (L.) Th. Fr. increases protection of Trebouxia photobionts from cadmium excess

Secondary metabolites of lichens can be involved in production of chelates with heavy metals. We hypothesized that parietin plays important role in protection of photobiont cells in Xanthoria parietina from an excess of cadmium ions. Two types of X. parietina lichen thalli, natural with presence of secondary metabolite parietin (p+) as well as without parietin (p−) were exposed to different doses of cadmium (up to 300 μmol g⁻¹ dw). Based on determination of the total and intracellular Cd-accumulation, ergosterol and thiobarbituric acid reactive substances (TBARS) content did not show statistically significant differences in the response of both types of thalli (p+ and p−). However, a stronger toxic effect of the highest Cd-dose on photosynthetic pigment content and chlorophyll a fluorescence was observed in the parietin-depleted thalli. The protective role of parietin against Cd excess was better supported and concluded from the differences observed in the production of non-protein thiol compounds (cysteine, glutathione and phytochelatins) involved in Cd detoxification. In the p+ thalli Cys content was stable but GSH content slightly decreased in the studied Cd range, while in the p− thalli these compounds were completely absent at high Cd doses. At Cd doses higher than 37.5 μmol Cd g⁻¹ dw, toxic to both types of X. parietina thalli, Cys and GSH contents were significantly higher in p+ than in p− thalli. Also, the photobiont partner in the p+ thalli was better protected of the metal exposition, and able to produce phytochelatins (PCs) over the whole range of metal, while in the p− thalli the production was completely inhibited at 75 μmol Cd g⁻¹ dw and higher concentrations, together with the inhibition of cysteine (Cys) and reduced glutathione (GSH) production. The obtained results indicate that the parietin layer is a natural barrier decreasing Cd access to algal cells in X. parietina. Comparison of PCs production appeared to be the most sensitive marker for estimation of Cd availability to photobiont in the symbiotic system.     

Nitrogen and carbon isotope variability in the green‐algal lichen Xanthoria parietina and their implications on mycobiont–photobiont interactions

Stable isotope patterns in lichens are known to vary largely, but effects of substrate on carbon and nitrogen stable isotope signatures of lichens were previously not investigated systematically. N and C contents and stable isotope (δ¹⁵N, δ¹³C) patterns have been measured in 92 lichen specimens of Xanthoria parietina from southern Bavaria growing on different substrates (bark and stone). Photobiont and mycobiont were isolated from selected populations and isotopically analyzed. Molecular investigations of the internal transcribed spacer of the nuclear ribosomal DNA (ITS nrDNA) region have been conducted on a subset of the specimens of X. parietina. Phylogenetic analysis showed no correlation between the symbionts X. parietina and Trebouxia decolorans and the substrate, isotope composition, or geographic origin. Instead specimens grown on organic substrate significantly differ in isotope values from those on minerogenic substrate. This study documents that the lichens growing on bark use additional or different N sources than the lichens growing on stone. δ¹⁵N variation of X. parietina apparently is controlled predominantly by the mass fraction of the mycobiont and its nitrogen isotope composition. In contrast with mycobionts, photobionts of X. parietina are much more ¹⁵N‐depleted and show less isotopic variability than mycobionts, probably indicating a mycobiont‐independent nitrogen acquisition by uptake of atmospheric ammonia.     

Biomonitoring of heavy metals in the coastal waters of two industrialised bays in southern Spain using the barnacle Balanus amphitrite

Abstract

This paper evaluates the bioavailability of As, Cd, Cu, Mn, Hg, Ni and Zn in the coastal waters of the two most important bays in southern Spain (Cádiz and Algeciras). Concentrations of these metals were measured in the bodies of Balanus amphitrite barnacles in 2005 and 2006. Seawater samples were collected from the same sites as the barnacles to assess metal concentrations and to gain additional information on the environmental conditions. Analysis of variance (ANOVA) showed significant geographic differences in the local bioavailability of metals to the barnacles, as reflected in the concentrations of accumulated metals. Balanus amphitrite accumulates large amounts of metals, with high concentration factors for Zn, Cd, Cu and Mn, in relation to the concentrations in marine waters.