Individual Thalli Research Articles

Three New Species and a New Record of the Lichen Genus Peltula (Peltulaceae) from Helan Mountain in China.

In this study, a systematic taxonomic analysis was carried out on the lichen genus Peltula, collected from Helan Mountain in China; three new species (Peltula helanense, P. overlappine, and P. reticulata) and a new record (P. crispatula (Nyl.) Egea) for China were identified. Four species were identified by morph-anatomical, chemical, and phylogenetic analyses by combining two gene loci (ITS and LSU). Peltula helanense is with tiny individual thalli up to 1mm, attached by creamy-white cylindrical rhizoids and apothecia filling the whole squamule. Peltula overlappine is characterized by thallus squamulose forming rosette-shaped patches and squamules with distinctive thickened margins. Peltula reticulata is characterized by brownish brown thallus and squamules with densely reticulate upper surface. P. crispatula is characterized by irregular squamules attached to a tuft of hyphae. The four species are described in detail, compared, and discussed with similar species, and images of morpho-anatomical structures of the four species are also provided. Moreover, a key to the species of Peltula from Helan Mountain is provided. The results enrich the data of the genus Peltula and also indicate that the rich diversity of lichen species in Helan Mountain is worthy of in-depth study.

Kelps on demand: Closed-system protocols for culturing large bull kelp sporophytes for research and restoration.

Culturing kelps for commercial, conservation, and scientific purposes is becoming increasingly widespread. However, kelp aquaculture methods are typically designed for ocean-based farms, and these methods may not be applicable for smaller scale cultivation efforts common in research and restoration. Growing kelps in closed, recirculating culture systems may address many of these constraints, yet closed system approaches have remained largely undescribed. Extensive declines of the bull kelp(Nereocystis luetkeana), an ecologically important canopy species in the Northeast Pacific, have received widespread attention and prompted numerous research and conservation initiatives. Here, we detail two approaches for cultivating N. luetkeana sporophytes in closed recirculating systems. Nereocystis luetkeana were reared as attached thalli in custom seaweed growth flumes and also free-floating in tumble culture tanks. Careful control of stocking density, water motion, aeration, and nutrient levels allowed for rapid growth and normal morphogenesis of laboratory-grown kelp. Culture systems reached up to 3 kg · m-3 , and individual thalli attained lengths of up to 6 m before the trials were terminated. Our results demonstrate the potential of recirculating, closed culture systems to overcome limitations associated with traditional culture methods. Recirculating systems enable the precise control of culture conditions, improving biosecurity and facilitating cultivar development and other research. Kelps can be grown away from the ocean or outside their native ranges, and seasonal or annual species can be produced year-round without seasonal constraints.

Stable isotope values (δ 13C, δ 15N) of macroalgal communities at Loch Creran and its relevance for elucidating sources of macroalgal organic carbon in fjordic sedimentary systems

Abstract Here, macroalgal isotopic values from Loch Creran, Western Scotland, were documented to determine the suitability of paired stable isotope analysis for identifying macroalgal-derived organic carbon sources in a fjordic sea loch. Variability in isotopic values (δ 13C and δ 15N) was evident within individual thalli of fucoid and kelp species, at the replicate level and between sampling localities. There were few consistent phylogenetic correlates in the isotopic values of macroalgae. The δ 13C ranges did, however, provide insight into differentiating between carbon sources more broadly, such as terrestrial from marine and between macrophyte lineages. As such, δ 13C could be indicative of the presence of macroalgal carbon sources within pools of organic matter but will likely be ineffective at separating these sources to lower taxonomic levels. Consequently, if these data are used alone to discriminate between macroalgal carbon sources and their relative contribution to a sedimentary pool of organic matter, the development of accurate conclusions will be challenging. The findings presented here demonstrate the need for complementary techniques or multi-tracer approaches to aid in the differentiation between macroalgal carbon sources to lower taxonomic levels rather than relying on stable isotopes as a biomarker alone.

Ethyl methanesulfonate mutant library construction in Neopyropia yezoensis to provide germplasm resources for next-generation genome-selection breeding

With the development of the laver industry, germplasm depression has become a serious issue, and current cultivars cannot adapt to different aquaculture regions. In order to increasing the genetic diversity and developing more germplasm sources, it is urgent and reasonable to construct a mutant library with more new germplasms. In this research, a mutant library was constructed by ethyl methanesulfonate (EMS)-mutagenized archeospores, and the most optimal treatment procedure was determined by performing different mutagen concentrations (2.25%) and treatment times (30 min). A total of 1860 haploid thalli were produced as the M1 mutant population and further cultured into conchocelis clones for the reservation of germplasm resources. Among these, 667 individual thalli were evaluated for their phenotypic traits, including thallus length, thallus width, length/width, thallus shape, photosynthesis ability, thallus color, thallus margin, and specific growth speed. The mutation frequency of the length/width ratio was 17.39%, Fv/Fm and NPQ were 21.84% and 29.35%, respectively, and SGR was 13.59%. The mutation frequency of thallus color was 0.91%. This work may not only provide a basic practical reference guide for EMS-based mutant library construction for other seaweeds but, more importantly, also serve as a valuable resource for functional genomics research and laver breeding.

Ontogenetic Variation in Blade Toughness May Contribute to the Spread of Turbinaria ornata Across the South Pacific.

Coral reefs are shifting from coral to algal-dominated ecosystems worldwide. Recently, Turbinaria ornata, a marine alga native to coral reefs of the South Pacific, has spread in both range and habitat usage. Given dense stands of T. ornata can function as an alternative stable state on coral reefs, it is imperative to understand the factors that underlie its success. We tested the hypothesis that T. ornata demonstrates ontogenetic variation in allocation to anti-herbivore defense, specifically that blade toughness varied nonlinearly with thallus size. We quantified the relationship between T. ornata blade toughness and thallus size for individual thalli within algal stands (N=345) on seven fringing reefs along the north shore of Moorea, French Polynesia. We found that blade toughness was greatest at intermediate sizes that typically form canopies, with overall reduced toughness in both smaller individuals that refuge within the understory and older reproductive individuals that ultimately detach and form floating rafts. We posit this variation in blade toughness reduces herbivory on the thalli that are most exposed to herbivores and may facilitate reproduction in dispersing stages, both of which may aid the proliferation of T. ornata.

Effect of Isolation Conditions on Diversity of Endolichenic Fungal Communities from a Foliose Lichen, Parmotrema tinctorum.

Endolichenic fungi (ELF) are emerging novel bioresources because their diverse secondary metabolites have a wide range of biological activities. Metagenomic analysis of lichen thalli demonstrated that the conventional isolation method of ELF covers a very limited range of ELF, and the development of an advanced isolation method is needed. The influence of four variables were investigated in this study to determine the suitable conditions for the isolation of more diverse ELF from a radially growing foliose lichen, Parmotrema tinctorum. Four variables were tested: age of the thallus, severity of surface-sterilization of the thallus, size of a thallus fragment for the inoculation, and nutrient requirement. In total, 104 species (1885 strains) of ELF were isolated from the five individual thalli of P. tinctorum collected at five different places. Most of the ELF isolates belong to Sordariomycetes. Because each part of lichen thallus (of different age) has unique ELF species, the whole thallus of the foliose lichen is needed to isolate diverse ELF. Moderate sterilization is appropriate for the isolation of diverse ELF. Inoculation of small fragment (1 mm2) of lichen thallus resulted in the isolation of highest diversity of ELF species compared to larger fragments (100 and 25 mm2). Moreover, ELF species isolated from the small thallus fragments covered all ELF taxa detected from the medium and the large fragments in this study. The use of two media—Bold’s basal medium (nutrient poor) and potato dextrose agar (nutrient rich)—supported the isolation of diverse ELF. Among the tested variables, size of thallus fragment more significantly influenced the isolation of diverse ELF than other three factors. Species composition and richness of ELF communities from different lichen thalli differed from each other in this study.

Decreasing in patch-size of Cystoseira forests reduces the diversity of their associated molluscan assemblage in Mediterranean rocky reefs

Canopy-forming seaweeds of the genus Cystoseira (Fucales, Phaeophyceae) form diverse and productive habitats along temperate rocky coasts of the Mediterranean Sea. During the last decade, Cystoseira forests have retracted their range considerably due to many interacting environmental, biological and anthropogenic pressures. We investigated how reducing in patch-size of C. montagnei affects their associated molluscan communities at the shallow northwest rocky shores of Palermo (Sicily, Italy). Molluscs were sampled from the fronds of individual thalli, clumps of 3 and 5 thalli of C. montagnei over an annual vegetative cycle (May–September) in two sites within the Marine Protected Area “Capo Gallo-Isola delle Femmine”. We measured five substrate attributes of the alga (thallus volume, canopy volume, interstitial volume, algal surface, and biomass) and explored their relationships with the diversity of the associated molluscan assemblage. A total of 3756 individuals of molluscs were collected, belonging to 30 families and 57 species, being Rissoidae the most speciose family and Barleeidae the dominant in terms of abundance. The molluscan assemblage on C. montagnei displayed significant spatial and seasonal variations, with the maximum number of individuals and species in summer, whereas evenness and diversity displayed maximum values in spring. The abundance, species richness and diversity of the molluscan assemblage decreased with decreasing in patch-size of C. montagnei, regardless of the vegetative phase of the alga or the sites considered in the study, while evenness showed an opposite trend. The substrate attributes of C. montagnei changed over the vegetative cycle of the alga and showed a similar pattern across sites with values that tended to decrease in autumn during the quiescence phase of the alga. Variation in patch-size of C. montagnei affected also the substrate attributes of the individual alga, with individual thalli becoming smaller with increasing patch-size. The algal surface of a single thallus of C. montagnei ranged on average from 956 cm2 in spring to 289 cm2 in autumn. Furthermore, algal surface together with thallus volume and dry weight were the substrate attributes that explained better the variation of the number of molluscan individuals and species. Overall, our results suggest that the reduction of both patch-size and algal substrate of C. montagnei forests altered the structure and composition of its associated molluscan assemblage. We argue that a reduction or loss of Cystoseira forests could probably trigger bottom-up effects in rocky shores habitats, with consequences for the whole ecosystem structure, functioning and services provided to humans.

Research on Growth Characteristics of Green-Tide-Forming Green Algae under Stress Conditions

The cytological characteristics of major green-tide-forming green algae Ulva prolifera collected from Yellow Sea were studied through cutting segments, long time low temperature or dark treatments. After being dried in the shade and preserved at -20°C for 30 days, the U. prolifera was cultured at 4°C in sterilized seawater under 40 μmol photons m-2·s-1 light intensity for 120 days, results indicated that the plastid of U. prolifera continuously shrank with the extension of treatment, and most cells turned white and died, only a small amount of cells still contained a few of visible inclusions at the 120d of treatment. Then those samples were transferred to 20°C and 40 μmol photons m-2·s-1 condition for recovery cultivation, after about 10 days, some recovery cells were observed in the thallus, and those cells developed to young thallus gradually and released germ cells almost in the same time. After about 60 days of recovery cultivation, the newly-grown green thallus broke through the original dead thallus, and the germ cells also grew to new individual thallus. Before dark treatment, the U. prolifera cells were filled with plastid, contained visible starch grain and discernible cell outlines, while after 120 days of dark treatment, the plastid shrank and degraded together with the disappearance of cell inclusions, and the cell outlines also blurred, then those samples were transferred to optimal culture conditions at 20°C in 40 μmol photons m-2·s-1 light intensity, and 15 days later, newly-grown cells appeared on the almost dead thallus, these cells divided continuously and grew to young thallus, and those newly-grown thallus also generated active germ cells, which developed to new thallus that cytologically identical to the original thallus. Observation of chopped tissue of U. prolifera cultivated at 20°C, 40 μmol m-2·s-1 showed that the morphological upper part cells turned to germ cells first, those germ cells including gametophyte and sporophyte, which released later and grew to new individual thallus. These findings provided cytological evidences for how U. prolifera live through stress conditions such as low temperature, darkness, and also useful for understanding the mechanism of the occurrence of green tide.

Seasonal Photosynthesis, Respiration, and Calcification of a Temperate Maërl Bed in Southern Portugal

Rhodolith (maerl) beds are biodiversity hotspots with a worldwide distribution. Maerl is the general term for free-living non-geniculate rhodoliths or coralline red algae. In southern Portugal, maerl beds are mainly composed by Phymatolithon lusitanicum, recently identified as a new species and commonly misidentified as Phymatolithon calcareum. Photosynthesis, respiration and growth rates of the algae were measured seasonally, as well as the photosynthetic pigment composition. To characterize the seasonal and interannual patterns of key abiotic conditions in the largest described maerl bed of the Portuguese coast, temperature, irradiance and dissolved oxygen were continuously monitored over a two-year period. At the bed depth (22 meters), temperature ranged between 14 oC in winter and 24 oC in summer, irradiance varied from 5 to 75 μmol m-2 s-1 and dissolved oxygen from 5.8 to 7.25 mgO2 L-1. We found a strong linear relationship (r2=0.95) between gross primary production (GPP) and relative electron transport rates (rETR). Both methods led to similar results and an average molar ratio of 0.24. Photosynthesis and respiration increased in summer and decreased in autumn and winter. In the summer of 2013 the growth rates where two fold higher (1.34 µmol CaCO3 g-1day-1) than in the other seasons. In winter and spring, to compensate for light deprivation and low temperature, algae increased their chlorophyll a and carotenoid concentrations while also decreasing their phycobilin concentration, in this case probably due to nutrient limitation. To isolate the role of temperature on the algae’s metabolism, the photosynthetic and respiration rates of individual thalli were measured at 8 different temperatures in the laboratory (from 12 to 26 oC). Phymatolithon lusitanicum photosynthesis increased 2-fold after a threshold of 18 oC (from 2.2 at 18 °C to 3.87 µmol O2 m-2 s-1 at 20 °C), whereas respiration increased 4-fold with temperature after a threshold of 22 o C (from -0.38 at 18 °C to -1.81 µmol O2 m-2 s-1 at 24 °C). The significant increases on respiration, photosynthetic rates and maximum growth with temperature reveal that the metabolic rates of P. lusitanicum are highly sensitive to ocean warming.

LA VEGETACIÓN ANTÁRTICA, CENTINELA DEL CAMBIO CLIMÁTICO

Antarctica is the coldest, driest, highest and windiest continent; the lichens and mosses grow where it is more warm, wet, low and protected. Overall productivity is strongly influenced by the length of period when water is available and the plants become, therefore, increasingly confined to areas of exceptionally good microclimate. It is this strong link between microclimate, water availability and productivity/growth that makes the system so potentially useful for monitoring global climate change, especially temperature increase. Even a small increase in temperature will markedly alter the areas over which such warm periods occur and bring with it a marked community shift. It is becoming clear that there are two Antarcticas, the Peninsula and the main continent. These differ in the controls on biodiversity distribution, there is a probably water unlimited but temperature-determined biodiversity cline in the Peninsula compared to a, water controlled, temperature-independent, fragmented vegetation in the continent. The reverse diel pattern of activity with the presence of very high light stress also seems to be confined to the continent. Several attempts have been made to use lichens as monitors of climate change especially in alpine and polar regions. The pristine Antarctica offers a unique opportunity to study the effects of climate change along a latitudinal gradient that extends between 62º and 87º S. Both lichen species diversity and thallus growth rate seem to show significant correlations to mean annual temperature and precipitation for gradients across the continent as well as to short time climate oscillation in the Antarctic Peninsula. Competition interactions appear to be small so that individual thalli develop in balance with environmental conditions and, as a result, can indicate the trends in productivity for discrete time intervals over long periods of time in a climate warming scenario.

Co-dominant anatomically disparate lichens converge in hydrological functional traits

Epiphytic lichens play a key hydrological role in ecosystems by intercepting and retaining water. These attributes can be characterized at an individual thallus scale by considering the retention and loss rates of water, themselves influenced by growth form and anatomy. We compared the hydrological attributes (water-holding capacity and standard drying rate) of two common northern temperate-boreal lichen genera, Evernia and Usnea, which differ greatly in internal anatomy. Despite conspicuous morphological and anatomical differences between the taxa that were hypothesized to affect thallus-water dynamics, their hydrological traits were found to be remarkably similar. This suggests either limited influence of internal anatomy on these ecologically relevant traits or convergence in hydrological attributes in co-occurring taxa.

Antarctic Studies Show Lichens to be Excellent Biomonitors of Climate Change

Lichens have been used as biomonitors for multiple purposes. They are well-known as air pollution indicators around urban and industrial centers. More recently, several attempts have been made to use lichens as monitors of climate change especially in alpine and polar regions. In this paper, we review the value of saxicolous lichens for monitoring environmental changes in Antarctic regions. The pristine Antarctica offers a unique opportunity to study the effects of climate change along a latitudinal gradient that extends between 62° and 87° S. Both lichen species diversity and thallus growth rate seem to show significant correlations to mean annual temperature for gradients across the continent as well as to short time climate oscillation in the Antarctic Peninsula. Competition interactions appear to be small so that individual thalli develop in balance with environmental conditions and, as a result, can indicate the trends in productivity for discrete time intervals over long periods of time.

Physiological responses to variations in grazing and light conditions in native and invasive fucoids

Poor physiological acclimatization to climate change has led to shifts in the distributional ranges of various species and to biodiversity loss. However, evidence also suggests the relevance of non-climatic physical factors, such as light, and biotic factors, which may act in interactive or additive way. We used a mechanistic approach to evaluate the ecophysiological responses of four seaweed species (three dominant intertidal fucoids, Fucus serratus, Ascophyllum nodosum, Bifurcaria bifurcata, and the invasive Sargassum muticum) to different conditions of grazing, light irradiance and ultraviolet (UV) radiation. We performed a large-scale mesocosm experiment with a total of 800 individual thalli of macroalgae. The factorial experimental design included major algal traits, photoacclimation, nutrient stoichiometry and chemical defence as response variables. Few significant effects of the factors acting alone or in combination were observed, suggesting a good capacity for acclimatization in all four species. The significant effects were generally additive and there were no potentially deleterious synergistic effects between factors. Fucus serratus, a species currently undergoing a drastic contraction of its southern distribution limit in Europe, was the most strongly affected species, showing overall lower photosynthetic efficiency than the other species. The growth rate of F. serratus decreased when UV radiation was filtered out, but only in the presence of grazers. Moreover, more individuals of this species tended to reach maturity in the absence of grazers, and the nitrogen content of tissues decreased under full-spectrum light. Only the phlorotannin content of tissues of B. bifurcata and of exudates of A. nodosum, both slow-growing species, were positively affected by respectively removal of UVB radiation and the presence of grazers. The findings for S. muticum, a well-established invasive seaweed across European coasts, suggested similar physiological response of this fast-growing species to different levels of grazing activity and light quality/intensity. As expected, this species grew faster than the other species. Bifurcaria bifurcata and A. nodosum only showed minor effects of light quality and grazing on phlorotannins content, which suggests good resistance of these two long-lived species to the experimental conditions. Mechanistic approaches that are designed to analyse interactive effects of physical and biotic factors provide an understanding of physiological responses of species and help to improve the confidence of predictive distribution models.

Carbon-based secondary compounds in the lichen Hypogymnia physodes deter detrivorous woodlice

Abstract Woodlice are not widely recognized as lichen-feeding invertebrates. We sought to discover whether the woodlouse, Porcellio scaber, could feed on the lichen Hypogymnia physodes and if the lichen carbon-based secondary compounds CBSCs would reduce grazing. We cut lichen thalli in two pieces, one was non-destructively rinsed in acetone to remove CBSCs; the other served as a control. Both pieces were fed to woodlice in a choice experiment. The CBSC concentration of individual thalli ranged from 3 to 19%. The woodlice grazed all pieces, but preferred the acetone-rinsed pieces, depending on the amount of CBSCs present in the non-extracted counterpart. The woodlice were not deterred from feeding on samples with CBSC concentrations ≤5%, which corresponded to natural contents in shade-adapted thalli. This suggested that P. scaber tolerates this amount of compounds at least in the short-term. In conclusion, P. scaber can feed on H. physodes, but CBSCs deter them from feeding.

Mismatch of morphological and molecular identifications in native and invasive subspecies of Codium fragile (Bryopsidophyceae, Chlorophyta).

Several subspecies are defined within Codium fragile, including the invasive C.fragile ssp. fragile, first reported in New Zealand in 1973. An endemic subspecies, C.fragile ssp. novae-zelandiae, is also found throughout New Zealand. The two subspecies exhibit morphological and molecular variation, although these have never been evaluated together. We compared variation between subspecies at locations in Auckland, identifying subspecies using rps3-rpl16 DNA sequence data, and assessing gross morphological differences, anatomical utricle characters and morphometrics. The taxonomic utility of the morphometric data sets was assessed by linear discriminant analysis. Utricle characters and measurements varied within individual thalli and between different preservation methods. The phenotypes of both subspecies were highly variable and influenced by environment. Accurate subspecies delimitation using morphological data was not possible; the discriminant analyses performed no better than chance for all combinations of the morphological data. Specimens from New Zealand, Canada, Australia and Ireland were sequenced using both the rps3-rpl16 and tufA plastid markers. The tufA elongation factor was shown to be a good candidate for differentiating subspecies of C.fragile. This marker is twice the length of the rps3-rpl16 spacer, shows greater variation between ssp. fragile and novae-zelandiae, and is less prone to sequencing error. A simple restriction enzyme digest of the tufA amplicon can distinguish ssp. fragile and ssp. novae-zelandiae. Our study expands the known range of the ssp. fragile in New Zealand, including the first record of this subspecies from the west coast of Auckland, and points to a need to re-evaluate morphological and molecular criteria for subspecies currently defined within C.fragile.

Desiccation tolerance in the chlorophyte green alga Ulva compressa: does cell wall architecture contribute to ecological success?

Main conclusionDesiccation leads to structural changes of the inner pectic cell wall layers inUlva compressa. This contributes to protection against mechanical damage due to desiccation–rehydration cycles.Ulva compressa, characterized by rbcL phylogeny, is a common species in the Mediterranean Sea. Ulva as an intertidal species tolerates repeated desiccation–rehydration cycles in nature; the physiological and structural basis were investigated under experimental conditions here. Desiccation to 73 % relative water content (RWC) led to a significant decrease of the maximum quantum yield of photosystem II (Fv/Fm) to about half of the initial value. A reduction to 48 or 27 % RWC caused a more drastic effect and thalli were only able to recover fully from desiccation to 73 % RWC. Relative electron transport rates were stimulated at 73 % RWC, but decreased significantly at 48 and 27 % RWC, respectively. Imaging-PAM analysis demonstrated a homogenous desiccation process within individual thallus discs. The different cell wall layers of U. compressa were characterized by standard staining procedures, i.e. calcofluor white and aniline blue for structural components (cellulose, callose), ruthenium red for pectins and toluidine blue for acidic polysaccharides. Already a reduction to 73 % RWC caused severe changes of the cell walls. The inner pectin-rich layers followed the shrinkage process of the cytoplasm, while the outer denser fibrillar layers maintained their shape. In this way, the thalli were not plasmolyzed during water loss, and upon recovery not negatively influenced by any mechanical damage. Transmission electron microscopy corroborated the arrangement of the different layers clearly distinguishable by their texture and electron density. We suggest the flexibility of the pectin-rich cell wall layers as a major contribution to desiccation tolerance in Ulva.Electronic supplementary materialThe online version of this article (doi:10.1007/s00425-015-2292-6) contains supplementary material, which is available to authorized users.

Location, location, location: small shifts in collection site result in large intraspecific differences in macroalgal palatability

The role of herbivorous fishes in coral reef resilience has increased interest in the process of herbivory and has focused attention on herbivore feeding behavior, making it important to evaluate experimental methods used to assess herbivore decisions. We tested whether small-scale differences in collection site play a role in within-species palatability of macroalgae. Baseline grazing assays using algae collected on a fringing reef in Moorea, French Polynesia, revealed that herbivore preferences among three common species ranked Padina boryana > Sargassum mangarevense ≫ Amansia rhodantha. Comparing grazing preferences between individual thalli of the same species collected <15 m apart revealed that consumption of intertidal S. mangarevense was nearly six times greater than for conspecifics collected from the adjacent subtidal reef flat. The same trend occurred for P. boryana but was not significant. This demonstrated that algal palatability can vary on a very small spatial scale, presenting a potential trap for the unwary when setting up experiments; we encourage researchers to consider this potential complication in experimental studies of herbivory.

Software Zur Flächenberechnung von Epiphytenbeständen

Abstract: Windisch, U. & Menzel, M. 2013. Software for determining the surface area of epiphytes. — Herzogia 26: 423–427. Longterm monitoring of epiphytes uses the film method adopting a recommendation of the VDI-guideline 3957 Part 8. In the field the outer contours of individual thalli are traced on a transparency film. The film is digitalized by scanning and prepared for calculation of the surface areas of lichens and bryophytes. A newly developed software is introduced. Based on an example the steps of evaluation are shown. There is a listing of the functions that are new compared to a previous evaluation software.

The genetic structure of the cosmopolitan three-partner lichenRamalina farinaceaevidences the concerted diversification of symbionts

The epiphytic lichen Ramalina farinacea is distributed throughout the northern hemisphere in which the same two algal Trebouxia species (provisionally named TR1 and TR9) coexist in every thallus. Ramalina farinacea symbionts were characterized based on the two fungal nuclear loci (nrITS and rpb2) along with the primary and secondary structures of nrITS from each Trebouxia species in the Iberian Peninsula and Canary Islands. The results indicated a noticeable genetic differentiation between mycobionts from these two geographic areas and also suggested concerted changes in the three partners of a lichen symbiosis toward two clearly distinguishable 'holobiont' lineages. Modeling of ITS2 RNA secondary structures suggested their temperature sensitivity in TR1 but not in TR9, which was consistent with the observed superior physiological performance of TR9 phycobionts under relatively high temperatures. Both TR1 and TR9 phycobionts have been also found in a variety of taxonomically distinct lichens with a preferably Mediterranean distribution, being TR1 much more widespread than TR9. Our observations support a model in which ecological diversification and speciation of lichen symbionts in different habitats could include a transient phase consisting of associations with more than one photobiont in individual thalli. Such diversification is likely to be promoted by different physiological backgrounds.

Trade-off between vegetative regeneration and sexual reproduction of Sargassum thunbergii

An ecological demographic study was conducted from January to December 2009 at Changshan Island on the northern side of Shandong Peninsula, China. The study investigated stem regeneration and the resource trade-off between sexual reproduction and vegetative regeneration of the brown alga Sargassum thunbergii at the individual thallus level. Stem regeneration from the holdfast occurred year round but with significant seasonality, peaking in the early summer. Both percentage of fertile stems and reproductive effort were negatively correlated with stem regeneration in the middle and later periods of sexual reproduction. Furthermore, the correlation coefficients increased significantly with time. These observations suggested that an increase in resource allocation to sexual reproduction would lead to a decrease in allocation to vegetative regeneration during the reproductive period. Reproductive effort was lower and stem regeneration was higher in the wave-exposed location compared with the sheltered location, indicating that allocation of resources between sexual reproduction and vegetative regeneration varied with location. When reproductive tissues were removed, the number of new stems produced from holdfasts increased, and when new stems were removed, an increase in reproductive effort occurred. These results suggest that trade-off between sexual reproduction and vegetative regeneration occurs in S. thunbergii.