Items 21-40 of 624

    • Journal Article

      Detecting differential viability selection between environments by analysis of compositional differentiation at different levels of genetic integration 

      Gillet, Elizabeth M.; Ziehe, Martin; Gregorius, Hans-Rolf
      Silvae Genetica 2016; 65(2) p.17-29
      Viability selection can be detected directly in an environment when the genotypes of the individuals at one ontogenetic stage (e.g. seeds) and the genotypes of the survivors at a later stage are both known, but genotypes at the earlier stage often cannot be determined. In this case, differential viability selection between environments can be detected as differences in the distributions of genetic types among survivors growing in different environments, provided that the survivors stem from random samples of seeds from the same base population (e.g. seed lot). Since common FST-outlier methods for detecting selected gene loci use only allele frequencies, selection that affects the higher hierarchical levels of genetic integration (single- or multi-locus genotypes) without changing allele frequencies is not noticed. A new method for detecting differential viability selection at any level of genetic integration enables discovery of elementary mechanisms of selection that older methods miss. It is based on two measures of compositional differentiation between environments. δSD measures qualitative differences between distributions of genetic types at any given integration level without regarding differences in their constituent alleles, while ΔSD measures quantitative differences between the same distributions by additionally considering the genic differences. The difference between these measures expresses the degree to which the patterns of gene association in the genotypes differ between environments. The P-values of all measures are estimated by permutation analysis under the assumption that survivors were randomly assigned to environments. Significance indicates the occurrence of differential viability selection at the loci. As a case study, a field study of viability in juvenile beech (Fagus sylvatica L.) for twelve enzyme loci is reanalyzed. It turns out that the significant differential selection for genotypes detected at three loci can be attributed to three combinations of selective effects: on alleles only (SKDHA), mostly alleles but also association patterns (LAP-A); interaction of effects on alleles and association patterns that are nonsignificant when viewed separately (AAT-B).
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    • Journal Article

      Above and below ground carbohydrate allocation differs between ash (Fraxinus excelsior L.) and beech (Fagus sylvatica L.) 

      Thoms, Ronny; Köhler, Michael; Gessler, Arthur; Gleixner, Gerd
      PLOS ONE 2017; 12(9): Art. e0184247
      We investigated soluble carbohydrate transport in trees that differed in their phloem loading strategies in order to better understand the transport of photosynthetic products into the roots and the rhizosphere as this knowledge is needed to better understand the respiratory processes in the rhizosphere. We compared beech, which is suggested to use mainly passive loading of transport sugars along a concentration gradient into the phloem, with ash that uses active loading and polymer trapping of raffinose family oligosaccharides (RFOs). We pulse-labeled 20 four-year old European beech and 20 four-year old ash trees with 13CO2 and tracked the fate of the label within different plant compartments. We extracted soluble carbohydrates from leaves, bark of stems and branches, and fine roots, measured their amount and isotopic content and calculated their turnover times. In beech one part of the sucrose was rapidly transported into sink tissues without major exchange with storage pools whereas another part of sucrose was strongly exchanged with unlabeled possibly stored sucrose. In contrast the storage and allocation patterns in ash depended on the identity of the transported sugars. RFO were the most important transport sugars that had highest turnover in all shoot compartments. However, the turnover of RFOs in the roots was uncoupled from the shoot. The only significant relation between sugars in the stem base and in the roots of ash was found for the amount (r2 = 0.50; p = 0.001) and isotopic content (r2 = 0.47; p = 0.01) of sucrose. The negative relation of the amounts suggested an active transport of sucrose into the roots of ash. Sucrose concentration in the root also best explained the concentration of RFOs in the roots suggesting that RFO in the roots of ash may be resynthesized from sucrose. Our results interestingly suggest that in both tree species only sucrose directly entered the fine root system and that in ash RFOs are transported indirectly into the fine roots only. The direct transport of sucrose might be passive in beech but active in ash (sustained active up- and unloading to co-cells), which would correspond to the phloem loading strategies. Our results give first hints that the transport of carbohydrates between shoot and root is not necessarily continuous and involves passive (beech) and active (ash) transport processes, which may be controlled by the phloem unloading.
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    • Journal Article

      Analysing taxonomic structures and local ecological processes in temperate forests in North Eastern China 

      Fan, Chunyu; Tan, Lingzhao; Zhang, Chunyu; Zhao, Xiuhai; von Gadow, Klaus
      BMC Ecology 2017; 17(1): Art. 33
      BACKGROUND: One of the core issues of forest community ecology is the exploration of how ecological processes affect community structure. The relative importance of different processes is still under debate. This study addresses four questions: (1) how is the taxonomic structure of a forest community affected by spatial scale? (2) does the taxonomic structure reveal effects of local processes such as environmental filtering, dispersal limitation or interspecific competition at a local scale? (3) does the effect of local processes on the taxonomic structure vary with the spatial scale? (4) does the analysis based on taxonomic structures provide similar insights when compared with the use of phylogenetic information? Based on the data collected in two large forest observational field studies, the taxonomic structures of the plant communities were analyzed at different sampling scales using taxonomic ratios (number of genera/number of species, number of families/number of species), and the relationship between the number of higher taxa and the number of species. Two random null models were used and the "standardized effect size" (SES) of taxonomic ratios was calculated, to assess possible differences between the observed and simulated taxonomic structures, which may be caused by specific ecological processes. We further applied a phylogeny-based method to compare results with those of the taxonomic approach. RESULTS: As expected, the taxonomic ratios decline with increasing grain size. The quantitative relationship between genera/families and species, described by a linearized power function, showed a good fit. With the exception of the family-species relationship in the Jiaohe study area, the exponents of the genus/family-species relationships did not show any scale dependent effects. The taxonomic ratios of the observed communities had significantly lower values than those of the simulated random community under the test of two null models at almost all scales. Null Model 2 which considered the spatial dispersion of species generated a taxonomic structure which proved to be more consistent with that in the observed community. As sampling sizes increased from 20 m × 20 m to 50 m × 50 m, the magnitudes of SESs of taxonomic ratios increased. Based on the phylogenetic analysis, we found that the Jiaohe plot was phylogenetically clustered at almost all scales. We detected significant phylogenetically overdispersion at the 20 m × 20 m and 30 m × 30 m scales in the Liangshui plot. CONCLUSIONS: The results suggest that the effect of abiotic filtering is greater than the effects of interspecific competition in shaping the local community at almost all scales. Local processes influence the taxonomic structures, but their combined effects vary with the spatial scale. The taxonomic approach provides similar insights as the phylogenetic approach, especially when we applied a more conservative null model. Analysing taxonomic structure may be a useful tool for communities where well-resolved phylogenetic data are not available.
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    • Journal Article

      Quantitative trait locus mapping of Populus bark features and stem diameter 

      Bdeir, Roba; Muchero, Wellington; Yordanov, Yordan; Tuskan, Gerald A.; Busov, Victor; Gailing, Oliver
      BMC Plant Biology 2017; 17(1): Art. 224
      BACKGROUND: Bark plays important roles in photosynthate transport and storage, along with physical and chemical protection. Bark texture varies extensively among species, from smooth to fissured to deeply furrowed, but its genetic control is unknown. This study sought to determine the main genomic regions associated with natural variation in bark features and stem diameter. Quantitative trait loci (QTL) were mapped using an interspecific pseudo-backcross pedigree (Populus trichocarpa x P. deltoides and P. deltoides) for bark texture, bark thickness and diameter collected across three years, two sites and three biological replicates per site. RESULTS: QTL specific to bark texture were highly reproducible in shared intervals across sites, years and replicates. Significant positive correlations and co-localization between trait QTL suggest pleiotropic regulators or closely linked genes. A list of candidate genes with related putative function, location close to QTL maxima and with the highest expression level in the phloem, xylem and cambium was identified. CONCLUSION: Candidate genes for bark texture included an ortholog of Arabidopsis ANAC104 (PopNAC128), which plays a role in lignified fiber cell and ray development, as well as Pinin and Fasciclin (PopFLA) genes with a role in cell adhesion, cell shape and migration. The results presented in this study provide a basis for future genomic characterization of genes found within the QTL for bark texture, bark thickness and diameter in order to better understand stem and bark development in Populus and other woody perennial plants. The QTL mapping approach identified a list of prime candidate genes for further validation using functional genomics or forward genetics approaches.
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    • Journal Article

      The Performance of Wood Decking after Five Years of Exposure: Verification of the Combined Effect of Wetting Ability and Durability 

      Humar, Miha; Kržišnik, Davor; Lesar, Boštjan; Brischke, Christian
      Forests 2019; 10(10): Art. 903
      Wood is one of the most important construction materials, and its use in building applications has increased in recent decades. In order to enable even more extensive and reliable use of wood, we need to understand the factors affecting wood’s service life. A new concept for characterizing the durability of wood-based materials and for predicting the service life of wood has recently been proposed, based on material-inherent protective properties, moisture performance, and the climate- and design-induced exposure dose of wooden structures. This approach was validated on the decking of a model house in Ljubljana that was constructed in October 2013. The decay and moisture content of decking elements were regularly monitored. In addition, the resistance dose DRd, as the product of the critical dose Dcrit, and two factors taking into account the wetting ability of wood (kwa) and its inherent durability (kinh), were determined in the laboratory. DRd correlated well with the decay rates of the decking of the model house. Furthermore, the positive effect of thermal modification and water-repellent treatments on the outdoor performance of the examined materials was evident, as well as the synergistic effects between moisture performance and inherent durability.
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    • Journal Article

      Wood Protection through Plasma Powder Deposition—An Alternative Coating Process 

      Köhler, Robert; Sauerbier, Philipp; Ohms, Gisela; Viöl, Wolfgang; Militz, Holger
      Forests 2019; 10(10): Art. 898
      In contrast to conventional coating processes such as varnishing, plasma powder deposition by means of an atmospheric pressure plasma jet on wood is not yet widely used. A key advantage of this process is that volatile organic compounds and organic solvents are avoided. In the present work, European beech (Fagus sylvatica L.) and pine sapwood (Pinus sylvestris L.) were coated with polymer (polyester), metal (aluminum coated silver) or metal oxide (bismuth oxide) particles. Furthermore, a layer system consisting of polyester and metal or metal oxide was investigated. The layer thickness and topography were analyzed with a laser scanning microscope and scanning electron microscope, revealing thicknesses of 2–22 µm depending on the coating material. In general, the chemical composition of the layers was determined using X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy measurements. The coatings consisting of metal and metal oxide showed a band gap and plasmon resonance in the range of 540 and 450 nm. Through this absorption, the wood may be protected against ultraviolet (UV) radiation. In the water uptake and release tests, the polyester layers exhibited a reduction of water vapor absorption after 24 h in 100% relative humidity (RH) by 53%–66%, whereas the pure metal oxide layers indicated the best desorption performance. The combination of metal oxide and polyester in the one-layer system combines the protection properties of the single coatings against water vapor and UV radiation
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    • Journal Article

      The scaling relationships of leaf biomass vs. leaf surface area of 12 bamboo species 

      Huang, Weiwei; Su, Xiaofei; Ratkowsky, David A.; Niklas, Karl J.; Gielis, Johan; Shi, Peijian
      Global Ecology and Conservation 2019; 20: Art. e00793
      There is convincing evidence for a scaling relationship between leaf dry weight (DW) and leaf surface area (A) for broad-leaved plants, and most estimates of the scaling exponent of DW vs. A are greater than unity. However, the scaling relationship of leaf fresh weight (FW) vs. A has been largely neglected. In the present study, we examined whether there is a statistically strong scaling relationship between FW and A and compared the goodness of fit to that of DW vs. A. Between 250 and 520 leaves from each of 12 bamboo species within 2 genera (Phyllostachys and Pleioblastus) were investigated. The reduced major axis regression protocols were used to determine scaling relationships. The fit for the linearized scaling relationship of FW vs. A was compared with that of DW vs. A using the coefficient of determination (i.e., r2). A stronger scaling relationship between FW and A than that between DW and A was observed for each of the 12 bamboo species investigated. Among the 12 species examined, five had significantly smaller scaling exponents of FW vs. A compared to those of DW vs. A; only one species had a scaling exponent of FW vs. A greater than that of DW vs. A. No significant difference between the two scaling exponents was observed for the remaining 6 species. Researchers conducting future studies might be well advised to consider the influence of leaf fresh weight when exploring the scaling relationships of foliar biomass allocation patterns.
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    • Journal Article

      Mapping Cellular Microenvironments: Proximity Labeling and Complexome Profiling (Seventh Symposium of the Göttingen Proteomics Forum) 

      Valerius, Oliver; Asif, Abdul R.; Beißbarth, Tim; Bohrer, Rainer; Dihazi, Hassan; Feussner, Kirstin; Jahn, Olaf; Majcherczyk, Andrzej; Schmidt, Bernhard; Schmitt, Kerstin; et al.
      Urlaub, HenningLenz, Christof
      Cells 2019; 8(10): Art. 1192
      Mass spectrometry-based proteomics methods are finding increasing use in structural biology research. Beyond simple interaction networks, information about stable protein-protein complexes or spatially proximal proteins helps to elucidate the biological functions of proteins in a wider cellular context. To shed light on new developments in this field, the Göttingen Proteomics Forum organized a one-day symposium focused on complexome profiling and proximity labeling, two emerging technologies that are gaining significant attention in biomolecular research. The symposium was held in Göttingen, Germany on 23 May, 2019, as part of a series of regular symposia organized by the Göttingen Proteomics Forum.
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    • Journal Article

      Antifreezing Hydrogel with High Zinc Reversibility for Flexible and Durable Aqueous Batteries by Cooperative Hydrated Cations 

      Zhu, Minshen; Wang, Xiaojie; Tang, Hongmei; Wang, Jiawei; Hao, Qi; Liu, Lixiang; Li, Yang; Zhang, Kai; Schmidt, Oliver G.
      Advanced Functional Materials: Art. 1907218
      Hydrogels are widely used in flexible aqueous batteries due to their liquid-like ion transportation abilities and solid-like mechanical properties. Their potential applications in flexible and wearable electronics introduce a fundamental challenge: how to lower the freezing point of hydrogels to preserve these merits without sacrificing hydrogels’ basic advantages in low cost and high safety. Moreover, zinc as an ideal anode in aqueous batteries suffers from low reversibility because of the formation of insulative byproducts, which is mainly caused by hydrogen evolution via extensive hydration of zinc ions. This, in principle, requires the suppression of hydration, which induces an undesirable increase in the freezing point of hydrogels. Here, it is demonstrated that cooperatively hydrated cations, zinc and lithium ions in hydrogels, are very effective in addressing the above challenges. This simple but unique hydrogel not only enables a 98% capacity retention upon cooling down to −20 °C from room temperature but also allows a near 100% capacity retention with >99.5% Coulombic efficiency over 500 cycles at −20 °C. In addition, the strengthened mechanical properties of the hydrogel under subzero temperatures result in excellent durability under various harsh deformations after the freezing process.
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    • Journal Article

      Comparison of three dielectric barrier discharges regarding their physical characteristics and influence on the adhesion properties on maple, high density fiberboards and wood plastic composite 

      Peters, F.; Hünnekens, B.; Wieneke, S.; Militz, H.; Ohms, G.; Viöl, W.
      Journal of Physics D: Applied Physics 2017; 50(47)
      In this study, three different dielectric barrier discharges, based on the same setup and run with the same power supply, are characterized by emission spectroscopy with regards to the reduced electrical field strength, and the rotational, vibrational and electron temperature. To compare discharges common for the treatment on wood, a coplanar surface barrier discharge, a direct dielectric barrier discharge and a jet system/remote plasma are chosen. To minimize influences due to the setups or power, the discharges are realized with the same electrodes and power supply and normalized to the same power. To evaluate the efficiency of the different discharges and the influence on treated materials, the surface free energy is determined on a maple wood, high density fiberboard and wood plastic composite. The influence is measured depending on the treatment time, with the highest impact in the time of 5 s.
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    • Journal Article

      Scaling Relationships between Leaf Shape and Area of 12 Rosaceae Species 

      Yu, Xiaojing; Hui, Cang; Sandhu, Hardev S.; Lin, Zhiyi; Shi, Peijian
      Symmetry 2019; 11(10)
      Leaf surface area (A) and leaf shape have been demonstrated to be closely correlated with photosynthetic rates. The scaling relationship between leaf biomass (both dry weight and fresh weight) and A has been widely studied. However, few studies have focused on the scaling relationship between leaf shape and A. Here, using more than 3600 leaves from 12 Rosaceae species, we examined the relationships of the leaf-shape indices including the left to right side leaf surface area ratio (AR), the ratio of leaf perimeter to leaf surface area (RPA), and the ratio of leaf width to length (RWL) versus A. We also tested whether there is a scaling relationship between leaf dry weight and A, and between PRA and A. There was no significant correlation between AR and A for each of the 12 species. Leaf area was also found to be independent of RWL because leaf width remained proportional to leaf length across the 12 species. However, there was a negative correlation between RPA and A. The scaling relationship between RPA and A held for each species, and the estimated scaling exponent of RPA versus A approached −1/2; the scaling relationship between leaf dry weight and A also held for each species, and 11 out of the 12 estimated scaling exponents of leaf dry weight versus A were greater than unity. Our results indicated that leaf surface area has a strong scaling relationship with leaf perimeter and also with leaf dry weight but has no relationship with leaf symmetry or RWL. Additionally, our results showed that leaf dry weight per unit area, which is usually associated with the photosynthetic capacity of plants, increases with an increasing A because the scaling exponent of leaf dry weight versus A is greater than unity. This suggests that a large leaf surface area requires more dry mass input to support the physical structure of the leaf.
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    • Journal Article

      Contrasting Global Patterns of Spatially Periodic Fairy Circles and Regular Insect Nests in Drylands 

      Getzin, Stephan; Yizhaq, Hezi; Cramer, Michael D.; Tschinkel, Walter R.
      Journal of Geophysical Research: Biogeosciences
      Numerical analysis of spatial pattern is widely used in ecology to describe the characteristics of floral and faunal distributions. These methods allow attribution of pattern to causal mechanisms by uncovering the specific signatures of patterns and causal agents. For example, grassland‐gap patterns called fairy circles (FCs) in Namibia and Australia are characterized by highly regular and homogenous distributions across landscapes that show spatially periodic ordering. These FCs have been suggested to be caused by both social insects and competitive plant interactions. We compared eight Namibian and Australian FC patterns and also modeled FCs to 16 patterns of social insect nests in Africa, Australia, and America that include the most regular termite mound patterns known. For pattern‐process inference, we used spatial statistics based on both nearest‐neighbor analysis and neighborhood‐density functions. None of the analyzed insect‐nest distributions attain the spatially periodic ordering that is typical of FCs. The inherently more variable patterns of termite and ant nests are commonly attributable to well documented aspects of the faunal life‐history. Our quantitative evidence from drylands shows that the more variable insect‐nest distributions in water‐limited environments cannot explain the characteristic spatial signature of FCs. The analysis demonstrates the interpretation of scale‐dependent neighborhood‐density functions and that it is the identification of unique spatial signatures in regular patterns that need to be linked to process. While our results cannot verify a specific hypothesis, they support the hypothesis that FCs in these drylands are more likely an emergent vegetation pattern caused by strong plant competition for water.
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    • Journal Article

      Episodic fluid flow in an active fault 

      Louis, Sarah; Luijendijk, Elco; Dunkl, István; Person, Mark
      Geology 2019; 47(10) p.938-942
      We present a reconstruction of episodic fluid flow over the past ∼250 k.y. along the Malpais normal fault, which hosts the Beowawe hydrothermal system (Nevada, USA), using a novel combination of the apatite (U-Th)/He (AHe) thermochronometer and a model of the thermal effects of fluid flow. Samples show partial resetting of the AHe thermochronometer in a 40-m-wide zone around the fault. Numerical models using current fluid temperatures and discharge rates indicate that fluid flow events lasting 2 k.y. or more lead to fully reset samples. Episodic fluid pulses lasting 1 k.y. result in partially reset samples, with 30–40 individual fluid pulses required to match the data. Episodic fluid flow is also supported by an overturned geothermal gradient in a borehole that crosses the fault, and by breaks in stable isotope trends in hydrothermal sinter deposits that coincide with two independently dated earthquakes in the past 20 k.y. This suggests a system where fluid flow is triggered by repeated seismic activity, and that seals itself over ∼1 k.y. due to the formation of clays and silicates in the fault damage zone. Hydrothermal activity is younger than the 6–10 Ma age of the fault, which means that deep (∼5 km) fluid flow was initiated only after a large part of the 230 m of fault offset had taken place.
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    • Journal Article

      Multiple components of plant diversity loss determine herbivore phylogenetic diversity in a subtropical forest experiment 

      Wang, Ming‐Qiang; Li, Yi; Chesters, Douglas; Anttonen, Perttu; Bruelheide, Helge; Chen, Jing‐Ting; Durka, Walter; Guo, Peng‐Fei; Härdtle, Werner; Ma, Keping; et al.
      Michalski, Stefan G.Schmid, BernhardOheimb, GoddertWu, Chun‐ShengZhang, Nai‐LiZhou, Qing‐SongSchuldt, AndreasZhu, Chao‐Dong
      Journal of Ecology 2019; 107(6) p.2697-2712
      Plant diversity loss can alter higher trophic -level communities via non -random species interactions, which in turn may cascade to affect key ecosystem func-tions. These non -random linkages might be best captured by patterns of phyloge-netic diversity, which take into account co -evolutionary dependencies. However,lack of adequate phylogenetic data of higher trophic levels hampers our mecha-nistic understanding of biodiversity relationships in species-rich ecosystems.2. We used DNA barcoding to generate data on the phylogenetic diversity of lepi-dopteran caterpillars in a large- scale forest biodiversity experiment in subtropicalChina. We analysed how different metrics of lepidopteran phylogenetic diversity(Faith's PD, MPD, MNTD) and taxonomic diversity were influenced by multiple components of tree diversity (taxonomic, functional, phylogenetic).3. Our data from six sampling periods represent 7,204 mitochondrial cytochrome c oxidase subunit I (COI) sequences of lepidopteran larvae, clustered into 461 mo-lecular operational taxonomic units. Lepidopteran abundance, the effective num-ber of species (irrespective of the focus on rare or common species) and Faith's PD and MPD (reflecting basal evolutionary splits), but not MNTD (reflecting re-cent evolutionary splits), significantly increased with experimentally manipulated ree species richness. Lepidopteran MNTD decreased with increasing tree MNTD. Path analyses showed that tree phylogenetic and functional diversity explained part, but not all of the effects of tree species richness on lepidopteran diversity. Importantly, tree diversity effects on lepidopteran diversity were to a large extent indirect, operating via changes in lepidopteran abundance. 4. Synthesis. Our study shows that evolutionary dependencies determine the response of herbivore communities to changes in host plant diversity. Incorporating a wider range of diversity metrics both at the level of producers and consumers can thus help to develop a more comprehensive understanding of the functional consequences of biodiversity change across trophic levels. Moreover, the dependence of trophic linkages on herbivore abundances underlines the need to address the consequences of current declines in insect abundances for ecosystem structure and functioning.
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    • Journal Article

      Rapid plant colonization of the forelands of a vanishing glacier is strongly associated with species traits 

      Franzén, Markus; Dieker, Petra; Schrader, Julian; Helm, Aveliina
      Arctic, Antarctic, and Alpine Research 2019; 51(1) p.366-378
      Recently developed glacier forelands provide valuable insights into vegetation dynamics. We studied the vascular plants in the glacier forelands of the Ålmajallojekna glacier in comparison to the plants in the surrounding area. The glacier is retreating rapidly at an average rate of 0.17 km2 per year from 1898 to 2012. In the newly emerged glacier forelands, we found that 32 percent of the 381 plant taxa occurred in the surrounding region. Sixty-eight plant species were present on the youngest terrain (0–31 y), an additional thirteen species occurred on terrain aged 32–53 years, and an additional forty-two species were detected on terrain aged 54–114 years. Of the surrounding species pool, plant species that had successfully established in recently deglaciated terrains were characterized by high regional abundance and low seed weight, and they were more likely to be members of the plant families Saxifragaceae, Salicaceae, and Asteraceae. Woody plant species with a preference for well-drained soils were more likely to be present in the youngest terrain. Our results show that the vegetation of glacier forelands is developing rapidly depending on the plant species in the surrounding area and the species’ life-history traits.
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      Climatologies at high resolution for the earth’s land surface areas 

      Karger, Dirk Nikolaus; Conrad, Olaf; Böhner, Jürgen; Kawohl, Tobias; Kreft, Holger; Soria-Auza, Rodrigo Wilber; Zimmermann, Niklaus E.; Linder, H. Peter; Kessler, Michael
      Scientific Data 2017; 4(1)
      High-resolution information on climatic conditions is essential to many applications in environmental and ecological sciences. Here we present the CHELSA (Climatologies at high resolution for the earth's land surface areas) data of downscaled model output temperature and precipitation estimates of the ERA-Interim climatic reanalysis to a high resolution of 30 arc sec. The temperature algorithm is based on statistical downscaling of atmospheric temperatures. The precipitation algorithm incorporates orographic predictors including wind fields, valley exposition, and boundary layer height, with a subsequent bias correction. The resulting data consist of a monthly temperature and precipitation climatology for the years 1979-2013. We compare the data derived from the CHELSA algorithm with other standard gridded products and station data from the Global Historical Climate Network. We compare the performance of the new climatologies in species distribution modelling and show that we can increase the accuracy of species range predictions. We further show that CHELSA climatological data has a similar accuracy as other products for temperature, but that its predictions of precipitation patterns are better.
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      Effect of Phosphinothricin on Transgenic Downy Birch (Betula pubescens Ehrh.) Containing bar or GS1 Genes 

      Lebedev; Krutovsky; Shestibratov
      Forests 2019; 10(12): Art. 1067
      Weeds are a big problem in agriculture and forestry, and herbicides are the main tools to control them. Phosphinotricin (ammonium glufosinate, PPT) is one of the most effective non-selective herbicides, to which weeds hardly gain resistance, but the reasons for its effect and toxicity to plants are still unclear, and especially, it is little studied in trees, including transgenic ones. We studied the physiological responses of downy birch (Betula pubescens Ehrh.) containing the herbicide resistance bar gene or the cytosol glutamine synthetase GS1 gene (the target enzyme of the herbicide) to PPT-based Basta herbicide treatment in various doses under open-air conditions during two years. Birch saplings with the bar gene were resistant to a double field dose (10 L/ha), but the expression of the GS1 gene only slightly increased resistance compared to the control. Herbicide treatment increased the ammonium level in leaf tissue by 3–8 times, but this, apparently, was not the main cause of plant death. Among leaf pigments, chlorophyll B was the most resistant to PPT, and carotenoids were the most sensitive. Responses of birch trees with the GS1 gene (accumulation of ammonium, pigment content, and dehydration) during treatment with a low dose of herbicide were less pronounced than in control plants. One-year-old control and transgenic plants with the GS gene died after 2.5 L/ha treatment, and two-year-old plants lost foliage after such treatment but remained alive and developed buds four weeks after treatment. Herbicide treatment of plants with the bar gene did not cause significant deviations in height (first year) or the accumulation of aboveground biomass (second year). The obtained results improve our understanding of the effect of PPT on woody plants and can be used both to clarify mechanisms of herbicide action and in plantation forestry.
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      Bamboo Water Transport Assessed with Deuterium Tracing 

      Mei, Tingting; Fang, Dongming; Röll, Alexander; Hölscher, Dirk
      Forests 2019; 10(8): Art. 623
      Bamboo water transport comprises the pathway rhizomes-culms-leaves as well as transfer among culms via connected rhizomes. We assessed bamboo water transport in three big clumpy bamboo species by deuterium tracing. The tracer was injected into the base of established culms, and water samples were collected from leaves of the labeled culms and from neighboring culms. From the base of labeled culms to their leaves, the average tracer arrival time across species was 1.2 days, maximum tracer concentration was reached after 1.8 days, and the tracer residence time was 5.6 days. Sap velocities were high (13.9 m d−1). Daily culm water use rates estimated by the tracer method versus rates measured by a calibrated sap flux method were highly correlated (R2 = 0.94), but the tracer estimates were about 70% higher. Elevated deuterium concentrations in studied neighbor culms point to deuterium transfer among culms, which may explain the difference in culm water use estimates. We found no differences in deuterium concentrations between neighbor-established and neighbor freshly sprouted culms of a given species. In two species, elevated concentrations in both neighbor-established and neighbor freshly sprouted culms were observed over an extended period. An applied mixing model suggests that five neighbor culms received labeled water. In contrast, for the third species, elevated concentrations in neighbor culms were only observed at the earliest sampling date after labeling. This could indicate that there was only short-term transfer and that the tracer was distributed more widely across the rhizome network. In conclusion, our deuterium tracing experiments point to water transfer among culms, but with species-specific differences.
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      Transcriptome profiling in Camellia japonica var. decumbens for the discovery of genes involved in chilling tolerance under cold stress 

      Wu, Yawen; Müller, Markus; Bai, Tian; Yao, Shunyang; Gailing, Oliver; Liu, Zhen
      Annals of Forest Research 2014; 62(1)
      Camellia japonica var. decumbens is a naturally occurring highly cold resistant variety of Camellia japonica which is suitable for snowy and cold regions. However, the underlying cold-adaptive mechanisms associated with gene regulation have been poorly investigated. We analyzed the transcriptomic changes caused by cold stress in a cold-tolerant accession. Samples were collected at the end of each temperature treatment (T1, T3, T5, T7 and T9 represent the temperatures 25°C, 0°C, -4°C, -8°C and -12°C, respectively). Sample T1 at 25°C was used as control. Based on transcriptome analysis, 2828, 2384, 3099 and 3075 differentially expressed genes (DEGs) were up-regulated, and 3184, 2592, 2373 and 2615 DEGs were down-regulated by analyzing T3/T1, T5/T1, T7/T1 and T9/T1, respectively. A gene ontology (GO) analysis revealed an enrichment of GO terms such as response to stimulus, metabolic process, catalytic activity or binding. Out of the larger number of DEGs, 67 functional and regulatory DEGs stood out, since they were functionally characterized in other models. These genes are cold-responsive transcription factors (26) or involved in cold sensor or signal transduction (17) and in the stabilization of the plasma membrane and osmosensing response (24). These results suggest rapid and multiple molecular mechanisms of perception, transduction and responses to cold stress in cold acclimation of Camellia japonica var. decumbens. They could also serve as a valuable resource for relevant research on cold-tolerance and help to explore cold-related genes to foster the understanding of low-temperature tolerance and plant-environment interactions.
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      Seasonal drivers of understorey temperature buffering in temperate deciduous forests across Europe 

      Zellweger, Florian; Coomes, David; Lenoir, Jonathan; Depauw, Leen; Maes, Sybryn L.; Wulf, Monika; Kirby, Keith J.; Brunet, Jörg; Kopecký, Martin; Máliš, František; et al.
      Schmidt, WolfgangHeinrichs, Steffiden Ouden, JanJaroszewicz, BogdanBuyse, GauthierSpicher, FabienVerheyen, KrisDe Frenne, Pieter
      Global Ecology and Biogeography 2019; 28(12) p.1774-1786
      Aim: Forest understorey microclimates are often buffered against extreme heat or cold, with important implications for the organisms living in these environments. We quantified seasonal effects of understorey microclimate predictors describing canopy structure, canopy composition and topography (i.e., local factors) and the forest patch size and distance to the coast (i.e., landscape factors). Location: Temperate forests in Europe. Time period: 2017–2018. Major taxa studied: Woody plants. Methods: We combined data from a microclimate sensor network with weather‐ station records to calculate the difference, or offset, between temperatures meas‐ ured inside and outside forests. We used regression analysis to study the effects of local and landscape factors on the seasonal offset of minimum, mean and maximum temperatures.
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