Recent Submissions

  • Journal Article

    Application of Wavelet De-Noising for Travel-Time Based Hydraulic Tomography 

    Yang, Huichen; Hu, Rui; Qiu, Pengxiang; Liu, Quan; Xing, Yixuan; Tao, Ran; Ptak, Thomas
    Water 2020; 12(6) p.1-23: Art. 1533
    Travel-time based hydraulic tomography is a promising method to characterize heterogeneity of porous-fractured aquifers. However, there is inevitable noise in field-scale experimental data and many hydraulic signal travel times, which are derived from the pumping test’s first groundwater level derivative drawdown curves and are strongly influenced by noise. The required data processing is thus quite time consuming and often not accurate enough. Therefore, an effective and accurate de-noising method is required for travel time inversion data processing. In this study, a series of hydraulic tomography experiments were conducted at a porous-fractured aquifer test site in Goettingen, Germany. A numerical model was built according to the site’s field conditions and tested based on diagnostic curve analyses of the field experimental data. Gaussian white noise was then added to the model’s calculated pumping test drawdown data to simulate the real noise in the field. Afterward, different de-noising methods were applied to remove it. This study has proven the superiority of the wavelet de-noising approach compared with several other filters. A wavelet de-noising method with calibrated mother wavelet type, de-noising level, and wavelet level was then determined to obtain the most accurate travel time values. Finally, using this most suitable de-noising method, the experimental hydraulic tomography travel time values were calculated from the de-noised data. The travel time inversion based on this de-noised data has shown results consistent with previous work at the test site.
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  • Journal Article

    Regeneration Dynamics Following the Formation of Understory Gaps in a Slovakian Beech Virgin Forest 

    Feldmann, Eike; Glatthorn, Jonas; Ammer, Christian; Leuschner, Christoph
    Forests 2020; 11(5) p.1-20: Art. 585
    The frequency and size of canopy gaps largely determine light transmission to lower canopy strata, controlling structuring processes in the understory. However, quantitative data from temperate virgin forests on the structure of regeneration in gaps and its dynamics over time are scarce. We studied the structure and height growth of tree regeneration by means of sapling density, shoot length growth and cumulative biomass in 17 understory gaps (29 to 931 m2 in size) in a Slovakian beech (Fagus sylvatica L.) virgin forest, and compared the gaps with the regeneration under closed-canopy conditions. Spatial differences in regeneration structure and growth rate within a gap and in the gap periphery were analyzed for their dependence on the relative intensities of direct and diffuse radiation (high vs. low). We tested the hypotheses that (i) the density and cumulative biomass of saplings are higher in gaps than in closed-canopy patches, (ii) the position in a gap influences the density and height growth of saplings, and (iii) height growth of saplings increases with gap size. Sapling density and biomass were significantly higher in understory gaps than under closed canopy. Density of saplings was positively affected by comparatively high direct, but low diffuse radiation, resulting in pronounced spatial differences. In contrast, sapling shoot length growth was positively affected by higher levels of diffuse radiation and also depended on sapling size, while direct radiation intensity was not influential. Conclusively, in this forest, regeneration likely becomes suppressed after a short period by lateral canopy expansion in small gaps (<100 m2), resulting in a heterogeneous understory structure. In larger gaps (≥100 m2) saplings may be capable even at low plant densities to fill the gap, often forming a cohort-like regeneration layer. Thus, gaps of different sizes imprint on the resulting canopy structure in different ways, enhancing spatial heterogeneity.
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  • Journal Article

    Consumers’ Evaluation of Stockfree-Organic Agriculture—A Segmentation Approach 

    Jürkenbeck, Kristin; Spiller, Achim
    Sustainability 2020; 12(10) p.1-19: Art. 4230
    Recently, more and more research has been conducted on what sustainable nutrition could look like. Stockfree-organic agriculture is one possible approach but a relatively new and unstudied cultivation method. In addition to organic agriculture, it excludes any animal by-products during the whole cultivation process. Among the consumers of organic food are especially many vegetarians and vegans. To attract this target group, first farms in Europe have started to follow the stockfree-organic agriculture principles. As it is important to know the consumers’ point of view on new developments in agriculture at an early stage of the diffusion process, this study deals with consumers’ evaluation of stockfree-organic agriculture to draw conclusions about a possible market potential. This is especially important for stockfree-organic farmers, as well as for organic farmers who are considering converting their cultivation method, and for retailers who wonder whether it is worthwhile to offer these products. The data was collected in 2019 by means of an online survey. The sample consisted of 500 German respondents. Principal component and cluster analyses were used to identify consumer segments according to their attitudes towards the acceptance, advantages, and disadvantages of stockfree-organic agriculture. Additionally, the different segments were compared with each other according to various attitudes and eating behaviours. Overall, animal welfare considerations and environmental aspects were of particular importance to consumers. Animal usage was clearly rejected by one segment, which contained 24% of the sample. Nearly all vegetarians and all vegans supported stockfree-organic agriculture, whereas heavy meat consumers tended to refuse the support of stockfree-organic agriculture. The supporting group valuing high animal welfare and health concerns was much larger than the current status of this niche segment would suggest. This could be a major challenge for the agricultural sector in the long term, but could also include opportunities for greater sustainability.
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  • Journal Article

    Modeling and Measuring Pre-Service Teachers’ Assessment Literacy Regarding Experimentation Competences in Biology 

    Joachim, Cora; Hammann, Marcus; Carstensen, Claus H.; Bögeholz, Susanne
    Education Sciences 2020; 10(5) p.1-27: Art. 140
    Assessment literacy is a crucial aspect of teachers’ professional knowledge and relevant to fostering students’ learning. Concerning experimentation, teachers have to be able to assess student achievement when students form hypotheses, design experiments, and analyze data. Therefore, teachers need to be familiar with criteria for experimentation as well as student conceptions of experimentation. The present study modeled and measured 495 German pre-service teachers’ knowledge of what to assess regarding experimentation competences in biology. We applied an open-answer format for the measurement instrument. For modeling we used item response theory (IRT). We argue that knowledge of what to assess regarding experimentation competences is a one-dimensional construct and we provide evidence for the validity of the measurement. Furthermore, we describe qualitative findings of pre-service teachers’ knowledge of what to assess, in particular difficulties concerning the assessment of student conceptions as well as the use of scientific terms in the assessments. We discuss the findings in terms of implications for science teacher education and further research perspectives.
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  • Journal Article

    Growth Performance of Local Chicken Breeds, a High-Performance Genotype and Their Crosses Fed with Regional Faba Beans to Replace Soy 

    Nolte, Tanja; Jansen, Simon; Weigend, Steffen; Moerlein, Daniel; Halle, Ingrid; Link, Wolfgang; Hummel, Jürgen; Simianer, Henner; Sharifi, Ahmad Reza
    Animals 2020; 10(4) p.1-19: Art. 702
    The faba bean (Vicia faba L.) is a native protein crop and considered a promising alternative to soybeans. Due to its anti-nutritive substances such as vicin and convicin (VC) its use in animal nutrition has been restricted. In the present study, two consecutive experiments were conducted to analyse the effects of feeding 20% faba beans, which differ in their VC content on fattening performance and slaughter traits of different chicken genotypes. In a first trial, purebred male chickens of the local breeds Bresse Gauloise and Vorwerkhuhn as well as of a high-performance White Rock line were tested. In a second trial, crossbreds of them were evaluated: Vorwerkhuhn $\times$ Bresse Gauloise, Vorwerkhuhn $\times$ White Rock, Bresse Gauloise $\times$ White Rock. Daily weight gain and feed intake were recorded until slaughter at approximately 2100 g. At slaughter the final live weight, carcass yield and the weights of the valuable parts (breasts and legs) were measured. For the genotypes studied, no adverse or undesirable effects of both VC-rich and VC-poor faba beans in the feedstuff were detected regarding body weight development, carcass quality, and fattening parameters. Furthermore, there was no indication that the birds’ health was impaired.
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  • Journal Article

    Sexual modulation in a polyploid grass: a reproductive contest between environmentally inducible sexual and genetically dominant apomictic pathways 

    Karunarathne, Piyal; Reutemann, Anna V.; Schedler, Mara; Glücksberg, Adriana; Martínez, Eric J.; Honfi, Ana I.; Hojsgaard, Diego H.
    Scientific Reports 2020; 10(1) p.1-14: Art. 8319
    In systems alternating between sexual and asexual reproduction, sex increases under unfavorable environmental conditions. In plants producing sexual and asexual (apomictic) seeds, studies on the influence of environmental factors on sex are equivocal. We used Paspalum intermedium to study environmental effects on the expression of sexual and apomictic developments, and on resulting reproductive fitness variables. Flow cytometric and embryological analyses were performed to characterize ploidy and reproductive modes, and effects of local climatic conditions on sexual and apomictic ovule and seed frequencies were determined. Seed set and germination data were collected and used to estimate reproductive fitness. Frequencies of sexual and apomictic ovules and seeds were highly variable within and among populations. Apomictic development exhibited higher competitive ability but lower overall fitness. Frequencies of sexual reproduction in facultative apomictic plants increased at lower temperatures and wider mean diurnal temperature ranges. We identified a two-fold higher fitness advantage of sexuality and a Tug of War between factors intrinsic to apomixis and environmental stressors promoting sexuality which influence the distribution of sex in apomictic populations. This points toward a crucial role of local ecological conditions in promoting a reshuffling of genetic variability that may be shaping the adaptative landscape in apomictic P. intermedium plants.
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  • Journal Article

    Epigenetic Patterns and Geographical Parthenogenesis in the Alpine Plant Species Ranunculus kuepferi (Ranunculaceae) 

    Schinkel, Christoph C. F.; Syngelaki, Eleni; Kirchheimer, Bernhard; Dullinger, Stefan; Klatt, Simone; Hörandl, Elvira
    International Journal of Molecular Sciences 2020; 21(9) p.1-20: Art. 3318
    Polyploidization and the shift to apomictic reproduction are connected to changes in DNA cytosine-methylation. Cytosine-methylation is further sensitive to environmental conditions. We, therefore, hypothesize that DNA methylation patterns would differentiate within species with geographical parthenogenesis, i.e., when diploid sexual and polyploid apomictic populations exhibit different spatial distributions. On natural populations of the alpine plant Ranunculus kuepferi, we tested differences in methylation patterns across two cytotypes (diploid, tetraploid) and three reproduction modes (sexual, mixed, apomictic), and their correlation to environmental data and geographical distributions. We used methylation-sensitive amplified fragment-length polymorphism (methylation-sensitive AFLPs) and scored three types of epiloci. Methylation patterns differed independently between cytotypes versus modes of reproduction and separated three distinct combined groups (2x sexual + mixed, 4x mixed, and 4x apomictic), with differentiation of 4x apomicts in all epiloci. We found no global spatial autocorrelation, but instead correlations to elevation and temperature gradients in 22 and 36 epiloci, respectively. Results suggest that methylation patterns in R. kuepferi were altered by cold conditions during postglacial recolonization of the Alps, and by the concomitant shift to facultative apomixis, and by polyploidization. Obligate apomictic tetraploids at the highest elevations established a distinct methylation profile. Methylation patterns reflect an ecological gradient rather than the geographical differentiation.
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  • Journal Article

    Effect of Alternative Protein Feeds on the Content of Selected Endogenous Bioactive and Flavour-Related Compounds in Chicken Breast Meat 

    Gkarane, Vasiliki; Ciulu, Marco; Altmann, Brianne; Mörlein, Daniel
    Foods 2020; 9(4) p.1-8: Art. 392
    Currently, soybean meal constitutes the main protein source for poultry production. However, the environmental and social issues related to soybean production are calling for more sustainable protein sources that can offset soybean requirements in animal production. Hermetia illucens larvae and the microalga spirulina (Arthrospira platensis) have proven to be effective alternatives to soybean meal for poultry production. In this study, the effect of 100% replacement of soy with partially defatted Hermetia illucens larvae and spirulina on the contents of selected endogenous bioactive (anserine, creatine and carnosine) and flavour-related (inosine and inosine-5´-monophosphate, IMP) compounds in chicken breast meat was evaluated. The results showed that the spirulina-based diet lowered the levels of anserine, carnosine and creatine compared to the control diet (3.3 vs. 4.1 mg/g, 0.15 vs. 0.72 mg/g and 1.49 vs. 2.49 mg/g, respectively) while IMP levels tended to be higher in spirulina-fed samples. Compared to the control group, Hermetia illucens-fed samples showed a lower content of bioactive peptides (anserine: 3.6 vs. 4.1 mg/g; carnosine: 0.39 vs. 0.72 mg/g; creatine: 2.03 vs. 2.49 mg/g), albeit to a lesser extent than the spirulina treatment group.
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  • Journal Article

    Hey, look over there: Distraction effects on rapid sequence recall 

    Miner, Daniel; Tetzlaff, Christian
    PLOS ONE 2020; 15(4) p.1-22: Art. e0223743
    In the course of everyday life, the brain must store and recall a huge variety of representations of stimuli which are presented in an ordered or sequential way. The processes by which the ordering of these various things is stored and recalled are moderately well understood. We use here a computational model of a cortex-like recurrent neural network adapted by a multitude of plasticity mechanisms. We first demonstrate the learning of a sequence. Then, we examine the influence of different types of distractors on the network dynamics during the recall of the encoded ordered information being ordered in a sequence. We are able to broadly arrive at two distinct effect-categories for distractors, arrive at a basic understanding of why this is so, and predict what distractors will fall into each category.
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  • Journal Article

    Encoding Information From Rotations Too Rapid To Be Consciously Perceived as Rotating: A Replication of the Motion Bridging Effect on a Liquid Crystal Display 

    Stein, Maximilian; Fendrich, Robert; Mattler, Uwe
    i-Perception 2020; 11(3) p.1-11: Art. 204166952092511
    A ring of points that is rotated so rapidly is perceived as a stationary outline circle that can induce an illusory rotation with the same spin direction in a subsequently presented ring of stationary points. This motion bridging effect (MBE) demonstrates that motion information can be conveyed by temporal frequencies generally thought to exceed the processing capabilities of the human visual system. It was first described in displays shown with an analog oscilloscope, but the rapid rotation rates needed to produce the MBE have heretofore prevented it from being investigated with conventional raster scan monitors. Here, we demonstrate the MBE can be reliably generated using the new generation of 240 Hz LCD gaming monitors, and exhibits basic characteristics similar to those reported previously. These monitors therefore provide a readily available resource for research on the MBE and the studies of the visual processing rapid motions in general.
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  • Journal Article

    Identification of Age-Specific and Common Key Regulatory Mechanisms Governing Eggshell Strength in Chicken Using Random Forests 

    Ramzan, Faisal; Klees, Selina; Schmitt, Armin Otto; Cavero, David; Gültas, Mehmet
    Genes 2020; 11(4) p.1-18: Art. 464
    In today’s chicken egg industry, maintaining the strength of eggshells in longer laying cycles is pivotal for improving the persistency of egg laying. Eggshell development and mineralization underlie a complex regulatory interplay of various proteins and signaling cascades involving multiple organ systems. Understanding the regulatory mechanisms influencing this dynamic trait over time is imperative, yet scarce. To investigate the temporal changes in the signaling cascades, we considered eggshell strength at two different time points during the egg production cycle and studied the genotype–phenotype associations by employing the Random Forests algorithm on chicken genotypic data. For the analysis of corresponding genes, we adopted a well established systems biology approach to delineate gene regulatory pathways and master regulators underlying this important trait. Our results indicate that, while some of the master regulators ($Slc22a1$ and $Sox11$) and pathways are common at different laying stages of chicken, others (e.g., $Scn11a$, $St8sia2$, or the TGF-$\beta$ pathway) represent age-specific functions. Overall, our results provide: (i) significant insights into age-specific and common molecular mechanisms underlying the regulation of eggshell strength; and (ii) new breeding targets to improve the eggshell quality during the later stages of the chicken production cycle.
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  • Journal Article

    Apomixis Technology: Separating the Wheat from the Chaff 

    Hojsgaard, Diego
    Genes 2020; 11(4) p.1-24: Art. 411
    Projections indicate that current plant breeding approaches will be unable to incorporate the global crop yields needed to deliver global food security. Apomixis is a disruptive innovation by which a plant produces clonal seeds capturing heterosis and gene combinations of elite phenotypes. Introducing apomixis into hybrid cultivars is a game-changing development in the current plant breeding paradigm that will accelerate the generation of high-yield cultivars. However, apomixis is a developmentally complex and genetically multifaceted trait. The central problem behind current constraints to apomixis breeding is that the genomic configuration and molecular mechanism that initiate apomixis and guide the formation of a clonal seed are still unknown. Today, not a single explanation about the origin of apomixis o er full empirical coverage, and synthesizing apomixis by manipulating individual genes has failed or produced little success. Overall evidence suggests apomixis arise from a still unknown single event molecular mechanism with multigenic e ects. Disentangling the genomic basis and complex genetics behind the emergence of apomixis in plants will require the use of novel experimental approaches benefiting from Next Generation Sequencing technologies and targeting not only reproductive genes, but also the epigenetic and genomic configurations associated with reproductive phenotypes in homoploid sexual and apomictic carriers. A comprehensive picture of most regulatory changes guiding apomixis emergence will be central for successfully installing apomixis into the target species by exploiting genetic modification techniques.
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  • Journal Article

    Improved Protocol for DNA Extraction from Subsoils Using Phosphate Lysis Buffer 

    Guerra, Victor; Beule, Lukas; Lehtsaar, Ena; Liao, Hui-Ling; Karlovsky, Petr
    Microorganisms 2020; 8(4) p.1-16: Art. 532
    As our understanding of soil biology deepens, there is a growing demand for investigations addressing microbial processes in the earth beneath the topsoil layer, called subsoil. High clay content in subsoils often hinders the recovery of suffcient quantities of DNA as clay particles bind nucleic acids. Here, an effcient and reproducible DNA extraction method for 200 mg dried soil based on sodium dodecyl sulfate (SDS) lysis in the presence of phosphate buffer has been developed. The extraction protocol was optimized by quantifying bacterial 16S and fungal 18S rRNA genes amplified from extracts obtained by different combinations of lysis methods and phosphate buffer washes. The combination of one minute of bead beating, followed by ten min incubation at 65°C in the presence of 1 M phosphate buffer with 0.5% SDS, was found to produce the best results. The optimized protocol was compared with a commonly used cetyltrimethylammonium bromide (CTAB) method, using Phaeozem soil collected from 60 cm depth at a conventional agricultural field and validated on five subsoils. The reproducibility and robustness of the protocol was corroborated by an interlaboratory comparison. The DNA extraction protocol offers a reproducible and cost-effective tool for DNA-based studies of subsoil biology.
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  • Journal Article

    Effect of Grazing System on Grassland Plant Species Richness and Vegetation Characteristics: Comparing Horse and Cattle Grazing 

    Schmitz, Anja; Isselstein, Johannes
    Sustainability 2020; 12(8) p.1-17: Art. 3300
    Horses are of increasing relevance in agriculturally managed grasslands across Europe. There is concern to what extent grazing with horses is a sustainable grassland management practice. The effect of longer-term horse grazing on the vegetation characteristics of grasslands has received little attention, especially in comparison to grazing cattle. Our study analyses the relative importance of grazing system (grazer species and regime) and grassland management for vegetation characteristics in grasslands as indicator for sustainable management. We monitored grassland vegetation in western central Germany and compared paddocks grazed by horses under two different regimes, continuous (HC) vs. rotational (HR), to paddocks grazed by cattle (C) under similar trophic site conditions. We observed more plant species and more High Nature Value indicator species on HC compared to C. The vegetation of C was more grazing tolerant and had higher forage value than HC. Regardless of the grazing regime, the competitive component was lower, the stress-tolerant component higher and the floristic contrast between patch-types stronger on HC and HR paddocks compared to C. Species richness was strongly influenced by the extent of the floristic contrast. Our results emphasize the potential of horse grazing for biodiversity in agriculturally managed grasslands.
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  • Journal Article

    Acceptance and Feasibility of a Guideline for the Animal Welfare Assessment of Fattening Pigs from Farmers’ Point of View 

    Pfeifer, Mareike; Koch, Alexandra; Lensches, Clara; Schmitt, Armin O.; Hessel, Engel F.
    Animals 2020; 10(4) p.1-14: Art. 711
    The welfare of farm animals is being increasingly discussed in society and politics. To evaluate animal welfare, indicator systems are often used. Such a system has been developed by the German Association for Technology and Structures in Agriculture and suggested in the publication “Animal Welfare Indicators: Practical Guide—Pigs”. The association’s aim is to provide farmers with a useful method for recording the welfare of pigs. Crucial for the acceptance of the guide by farmers is a high degree of feasibility of the recommended indicators as well as the proposed methods for their recording. To evaluate this, 40 farmers keeping fattening pigs were interviewed. The guided semi-structured interview was conducted on the farms after the farmers evaluated the welfare of their fattening pigs according to the guide. The results are: Apart from the indicators faecal soiling and tail length, all the other eleven indicators are accepted for the assessment of fattening pig welfare by a majority of the interviewed farmers (between 57.5% and 90% acceptance per indicator). Furthermore, the feasibility of the individual indicators was assessed as being positive. The relationship between time expenditure and benefit was rated on a five-point scale at an average of 3.1 (medium), which clearly shows that there is a need for further development of this guide. Some possible changes with a potential for improvement could be identified; for example, the aggregation of the results after the collection of the individual indicators to an overall result that can be compared and interpreted.
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  • Journal Article

    Precipitation is the most crucial factor determining the distribution of moso bamboo in Mainland China 

    Shi, Peijian; Preisler, Haiganoush K.; Quinn, Brady K.; Zhao, Jie; Huang, Weiwei; Röll, Alexander; Cheng, Xiaofei; Li, Huarong; Hölscher, Dirk
    Global Ecology and Conservation 2020; 22 p.1-15: Art. e00924
    Moso bamboo is widespread in natural forests and is cultivated over large areas in China. This study investigated how climate controls its distribution, about which little is known. We collected moso bamboo presence-absence data from 674 sites with long-term climate data in Mainland China. Generalized additive models that included location and climate variables were used to test the effects of these predictors on the species’occurrence. We identified the best model as the one with the lowest Akaike’s Information Criterion value that contained only statistically significant predictors. We found precipitation, especially the mean (APRE) and interannual standard deviation (SDPRE) of the annual precipitation at each site, rather than temperature, to be the main factors determining the distribution of moso bamboo in Mainland China. In addition, we found that there was a significant power law relationship between the mean and interannual variance of precipitation, which made it possible to make long-term predictions. The SDPRE in climate scenarios of changes in the APRE could then be calculated using thefitted power law relationship. We simulated six climate scenarios, in which the APRE increased/decreased by 25, 50, and 75%. We used the 0.5 and 0.9 probability contour lines of model predictions to represent the suitable and core distributions, respectively, of moso bamboo under each scenario. The current core distribution of moso bamboo in Mainland China predicted by our model agreed with actual observations. Our model suggested that the middle and lower reaches of the Huaihe River Plain in eastern China should be climatically suitable for the growth of moso bamboo; it seems likely that its current absence there has resulted from intensive land use. Our model predicted that changes in APRE can strongly alter the distribution of moso bamboo. Increased APRE would expand the core distribution of moso bamboo into southern Shandong Province and over all of Chongqing and most of Guizhou Provinces, which are areas not currently in the species’core distribution. Conversely, decreased APRE would shrink the core distribution of moso bamboo to the junction of Anhui, Fujian, Jiangxi, and Zhejiang Provinces. We showed that the current distribution of moso bamboo is mainly determined by annual precipitation rather than temperature. The deviations between the moso distributions predicted by the climate model and the current distribution in some plain areas might have resulted from human activities. Future changes in annual precipitation will probably change the distribution of moso bamboo considerably.
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  • Journal Article

    Mycorrhizal Phosphorus Efficiencies and Microbial Competition Drive Root P Uptake 

    Clausing, Simon; Polle, Andrea
    Frontiers in Forests and Global Change 2020; 3 p.1-15: Art. 54
    Phosphorus (P) availability shows large differences among different soil types, affecting P nutrition of forest trees. Chemical binding of P to soil moieties affects partitioning of P between soil particles and solution, influencing soluble P concentrations upon which plants, their associated mycorrhizal symbionts, and microbes feed. The goal of this study was to characterize root P uptake by mycorrhizal and non-mycorrhizal root tips in competition with microbes in situ in the organic and mineral layer of a P-rich and a P-poor forest. We used intact soil cores (0.2 m depth) from beech (Fagus sylvatica) forests to tracing the fate of $^{33}$P in soil, plant and microbial fractions.We used the dilution of $^{33}$P in the rhizosphere of each soil layer to estimate the enrichment with new P in mycorrhizal and non-mycorrhizal root tips and root P uptake. In soil cores from P-rich conditions, 25 and 75% of root P uptake occurred in the organic and mineral layer, respectively, whereas in the P-poor forest, 60% occurred in the organic and 40% in the mineral layer. Mycorrhizal P efficiency, determined as enrichment of new P in mycorrhizal root tips, differed between soil layers. Root P uptake was correlated with mycorrhizal P efficiency and root tip abundance but not with root tip abundance as a single factor. This finding underpins the importance of the regulation of mycorrhizal P acquisition for root P supply. The composition of mycorrhizal assemblages differed between forests but not between soil layers. Therefore, differences in P efficiencies resulted from physiological adjustments of the symbionts. Non-mycorrhizal root tips were rare and exhibited lower enrichment with new P than mycorrhizal root tips. Their contribution to root P supply was negligible. Microbes were strong competitors for P in P-poor but not in P-rich soil. Understory roots were present in the P-rich soil but did not compete for P. Our results uncover regulation of mycorrhizal P efficiencies and highlight the complexity of biotic and abiotic factors that govern P supply to trees in forest ecosystems.
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  • Journal Article

    Tail Lesions and Losses of Docked and Undocked Pigs in Different Farrowing and Rearing Systems 

    Gentz, Maria; Lange, Anita; Zeidler, Sebastian; Lambertz, Christian; Gauly, Matthias; Burfeind, Onno; Traulsen, Imke
    Agriculture 2020; 10(4) p.1-11: Art. 130
    This study aimed to investigate the effects of farrowing and rearing systems on tail lesions and losses of docked and undocked pigs. Pigs from three farrowing systems: Conventional farrowing crate (FC), free farrowing (FF) and group housing of lactating sows (GH) were randomly allocated to different rearing systems: A conventional system (CONV), where the pigs were regrouped and transferred to conventional finishing pens at ten weeks of age or a wean-to-finish (W-F) system, where the pigs remained in their pens until slaughter with higher space allowance during rearing. Weekly, tail lesions and losses were assessed individually. The incidence of tail lesions was higher in undocked CONV pigs compared to undocked W-F pigs (maximum: CONV 58.01%, W-F 41.16%). The rearing system had a significant effect on tail losses at the end of finishing (CONV 67.63%,W-F 38.2%). The significant effect of the rearing system might be explained by higher space allowance during rearing and reduced regrouping stress forW-F pigs. In conclusion, farrowing systems showed no effects, but the W-F rearing system reduces the frequency of tail lesions and losses; the curves of tail lesions increased slower and stayed on a lower level, which resulted in lower losses as well.
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  • Journal Article

    Performance of Modern Varieties of Festuca arundinacea and Phleum pratense as an Alternative to Lolium perenne in Intensively Managed Sown Grasslands 

    Becker, Talea; Isselstein, Johannes; Jürschik, Rena; Benke, Matthias; Kayser, Manfred
    Agronomy 2020; 10(4) p.1-13: Art. 540
    In future, grass swards need to be adapted to climate change and interactions of management and site are becoming more important. The persistence of Lolium perenne on peatland or during dry periods is limited and alternative forage species are required. We tested the performance of a modern variety of Festuca arundinacea and Phleum pratense as an alternative to Lolium perenne on clay, peat, and sandy soils. Each of these grasses was sown as main species in mixture with Poa pratensis and Trifolium repens and the mixtures were subjected to different frequencies of defoliation. Differences in yield proportions in the third year were significantly influenced by main species, site and their interaction. Remaining mass proportions of main species after three years were smallest on peat; on all sites Festuca arundinacea showed the highest persistence and largest yield, followed by Lolium perenne. Mass proportions of Phleum pratense were small on peat soils and Phleum had been replaced there by Holcus lanatus, and by Lolium perenne and Poa pratensis on the clay and sandy soils. We conclude that the choice of grass species in mixtures is a management tool to control stability and productivity of grass swards under specific site conditions.
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  • Journal Article

    High-Resolution Melting (HRM) Curve Assay for the Identification of Eight Fusarium Species Causing Ear Rot in Maize 

    Schiwek, Simon; Beule, Lukas; Vinas, Maria; Pfordt, Annette; von Tiedemann, Andreas; Karlovsky, Petr
    Pathogens 2020; 9(4) p.1-13: Art. 270
    Maize plants are often infected with fungal pathogens of the genus Fusarium. Taxonomic characterization of these species bymicroscopic examination of pure cultures or assignment to mating populations is time-consuming and requires specific expertise. Reliable taxonomic assignment may be strengthened by the analysis of DNA sequences. Species-specific PCR assays are available for most Fusarium pathogens, but the number of species that infect maize increases the labor and costs required for analysis. In this work, a diagnostic assay for major Fusarium pathogens of maize based on the analysis of melting curves of PCR amplicons was established. Short segments of genes RPB2 and TEF-1$\alpha$, which have been widely used in molecular taxonomy of Fusarium, were amplified with universal primers in a real-time thermocycler and high-resolution melting (HRM) curves of the products were recorded. Among major Fusarium pathogens of maize ears, F. cerealis, F. culmorum, F. graminearum, F. equiseti, F. poae, F. temperatum, F. tricinctum, and F. verticillioides, all species except for the pair F. culmorum/F. graminearum could be distinguished by HRM analysis of a 304 bp segment of the RPB2 gene. The latter two species could be differentiated by HRM analysis of a 247 bp segment of the TEF-1$\alpha$gene. The assay was validated with DNA extracted from pure cultures of fungal strains, successfully applied to total DNA extracted from infected maize ears and also to fungal mycelium that was added directly to the PCR master mix (“colony PCR”). HRM analysis thus offers a cost-efficient method suitable for the diagnosis of multiple fungal pathogens.
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