The prevalence of anti-yersinia outer protein antibodies in Bavarian slaughter pigs

The aim of the present study was to provide current data on the prevalence of anti-Yersinia-antibodies in Bavarian slaughtering pigs. The recomBlot Westernblot assay based on five recombinantly produced Yersinia Outer Proteins (YopD, YopE, YopH, YopM, V-antigen) is well evaluated for the use in the diagnosis of human yersiniosis and proved to be also a valuable tool for the detection of porcine antibodies. 965 out of 1002 meat juice samples collected in 53 Bavarian pig farms contained anti-Yop/V-Ag-antibodies. Only blots with three or more detectable signals were considered as positive. On the basis of these results a possible previous history of Yersinia infection was detected in 45.4% of the pigs and all of the pig farms. The high prevalence of anti-Yersinia-antibodies found in this investigation demonstrates the need for further epidemiological surveillance and animal studies to assess consumers' endangering.     

Influence of measuring angle,nitrogen fertilization,and variety on spectral reflectance of winter oilseed rape canopies

A field experiment with winter oilseed rape was conducted near Göttingen (northern Germany) in the growing season 1998–99. Twelve varieties were compared at two nitrogen (N) application rates (0, 206 kg N ha^–1) regarding shoot dry matter production, shoot N content, shoot N uptake (beginning of shooting, beginning of flowering), and seed yield. Canopy reflectance was measured one week before the beginning of shooting and one week before flowering at different wavelengths between 550 and 940 nm using a spectral reflectance sensor, type FAL II. The vegetation indices red edge inflection point (RIP), soil adjusted vegetation index (SAVI), and normalized vegetation index (NDVI) introduced in literature as indicators of growth parameters were calculated from the reflectance values and compared with growth parameters. The results showed that the measuring angle (–45° to 45°) had a significant influence on the calculated vegetation indices. Therefore, the measuring angle should be kept constant during the measurements. Nitrogen fertilization led to an increase of all vegetation indices. The results revealed significant differences between the tested varieties, indicating problems regarding an accurate estimation of the N status of the crop. Consistent differences in the vegetation indices appeared between varieties with extremely different growth parameters. However, no general relationship between growth parameters and vegetation indices of the 12 varieties could be found. Therefore, variety‐specific calibrations are necessary. The indices RIP and SAVI resulted in similar statements and seem to be good parameters regarding N effects and variety differences, whereas NDVI could resolve variety differences in the fertilized treatments only imperfectly.     

Uncertainty analysis of a dynamic vapor sorption-fast gas chromatography-flame ionization detection method for the rapid analysis of volatile release from glassy matrices

Uncertainty analysis was conducted with a dynamic vapor sorption-fast gas chromatography-flame ionization detection (DVS-fast GC-FID) method, developed to rapidly analyze the extent of volatile release that occurs from carbohydrate glasses due to humidification and temperature increases. Triplicate samples progressed through a two-step special automatic operation method in the DVS. Samples were exposed to relative humidities ranging from 40 to 90% (in 10% increments) at 15, 25, and 35 degrees C. Uncertainty analysis shows that the DVS-fast GC-FID method uncertainty is smaller than the natural sample uncertainty, indicating that the variability in a sample's physical properties has a dominant impact on the overall uncertainty of the volatile retention results obtained using the DVS-fast GC-FID method. Uncertainty analysis also indicates that the variance associated with the mass of benzaldehyde measured by the DVS-fast GC-FID is the largest contributor to the overall benzaldehyde retention variance when the cumulative mass of benzaldehyde measured is small.     

Priming negatively affects feeding behaviour and aphid biomass of Rhopalosiphum padi on barley

Plants have developed numerous strategies for responding to abiotic and biotic stresses. In particular, the microbiota surrounding plants may have a positive effect on plant stress responses. One is the reaction to rhizobacteria, which can lead to induced systemic resistance. Gram-negative soil bacteria that produce N-acyl homoserine lactones (AHL), for example, Ensifer meliloti, induce a primed state in plants that is part of the inducible resistance phenomenon. Observing Rhopalosiphum padi feeding behaviour on a priming sensitive barley genotype, treated with the AHL-producing E. meliloti strain expR?+?ch, using electrical penetration graph technique showed decreased ingestion of food. Aphids appear to overcome this effect within the eight-hour observation period, possibly explaining the absence of differences of reproduction. Reproduction was observed for a period of 14 days on primed and control-treated plants. Long-term observations over a period of 40 days after aphid infestation showed a lower aphid biomass in contrast to a control group, interpreted as delayed population growth, and an increase in the biomass of barley plants. Priming-related genotypic effects of the defence response to aphids were observed, with no beneficial effects on the plant genotype when its sensitivity to priming was low. Previously, an AHL-priming sensitive barley genotype showed enhanced resistance against fungi when primed with the expR?+?ch strain of E. meliloti. The present study reports the same effect against R. padi. These findings suggest that sensitivity to AHL-priming may represent a new approach for plant breeding, targeting multiple pests in parallel by induced plant resistance.

     

Production physiology of three native shrubs intercropped in a young longleaf pine plantation

The objective of this study was to evaluate how competition would affect the physiology, and thus productivity of American beautyberry (Callicarpa americana L.), wax myrtle [Morella cerifera (L.) Small] and inkberry [Ilex glabra (L.) A. Gray] when intercropped in a longleaf pine (Pinus palustris Mill.) plantation in the southeastern United States. The effect of competition was assessed via comparisons of mortality, biomass, light transmittance, gas exchange and soil moisture between intercropping and monoculture (treeless) treatments. Overall, shrubs in the intercropping treatment performed worse than those in the monoculture, with higher mortality, and reductions in biomass of 75.5, 50.6, and 68.7% for C. americana, M. cerifera and I. glabra, respectively. Root–shoot ratios for all species were significantly higher and soil moisture during dry periods was significantly lower in the intercropping treatment. Light transmittance below the pine canopy was high (57.7%) and I. glabra was the only species that exhibited reduced A _max when belowground resources were not limiting. These results suggest that the effect of shading is minimal and belowground competition is likely the most important determinant of productivity in this system.     

A generalized algebraic difference approach allows an improved estimation of aboveground biomass dynamics of <Emphasis Type="Italic">Cunninghamia lanceolata</Emphasis> and <Emphasis Type="Italic">Castanopsis sclerophylla</Emphasis> forests

Key message

A generalized algebraic difference approach (GADA) developed in this study improved the estimation of aboveground biomass dynamics of Cunninghamia lanceolata (Lamb.) Hook and Castanopsis sclerophylla (Lindl.) Schott forests. This could significantly improve the fieldwork efficiency for dynamic biomass estimation without repeated measurements.

Context

The estimation of biomass growth dynamics and stocks is a fundamental requirement for evaluating both the capability and potential of forest carbon sequestration. However, the biomass dynamics of Cunninghamia lanceolata and Castanopsis sclerophylla using the generalized algebraic difference approach (GADA) model has not been made to date.

Aims

This study aimed to quantify aboveground biomass (AGB, including stem, branch and leaf biomass) dynamics and AGB increment in C. lanceolata and C. sclerophylla forests by combining a GADA for diameter prediction with allometric biomass models.

Methods

A total of 12 plots for a C. lanceolata plantation and 11 plots for a C. sclerophylla forest were selected randomly from a 100 m × 100 m systematic grid placed over the study area. GADA model was developed based on tree ring data for each stand.

Results

GADA models performed well for diameter prediction and successfully predicted AGB dynamics for both stands. The mean AGB of the C. lanceolata stand ranged from 69.4 ± 7.7 Mg ha^?1 in 2010 to 102.5 ± 11.4 Mg ha^?1 in 2013, compared to 136.9 ± 7.0 Mg ha^?1 in 2010 to 154.8 ± 8.0 Mg ha^?1 in 2013 for C. sclerophylla. The stem was the main component of AGB stocks and production. Significantly higher production efficiency (stem production/leaf area index) and AGB increment was observed for C. lancolata compared to C. sclerophylla.

Conclusion

Dynamic GADA models could overcome the limitations posed by within-stand competition and limited biometric data, can be applied to study AGB dynamics and AGB increment, and contribute to improving our understanding of net primary production and carbon sequestration dynamics in forest ecosystems.

     

Large-scale reduction of ungulate browsing by managed sport hunting

Browsing by free-living ungulates is a serious threat to forest regeneration. Although predictors of browsing and potential consequences are well researched, less information is available in the scientific literature about possible solutions to the problem. We investigated whether a large-scale game management system in a traditional sport hunting culture has the potential to effectively reduce browsing damage. Our analysis was based on browsing survey data from 2006 and 2009 covering more than 25,000 km² in Bavaria, Germany. After an initial assessment of browsing damage throughout Bavaria in 2006, game management plans were altered, and the effect of this intervention was assessed in 2009. Browsing damage clearly declined in 2009 in areas where the suggested deer harvests were increased in 2006 game management plans. This is the first report of a successful implementation of a large-scale game management system aiming at reducing browsing damage to facilitate unfenced forest regeneration.     

Resistance against <Emphasis Type="Italic">Fusarium graminearum</Emphasis> and the relationship to β-glucan content in barley grains

Fusarium head blight (FHB) caused by Fusarium graminearum (FG) is a destructive disease impacting barley worldwide. The disease reduces the grain yield and contaminates grains with mycotoxins, such as the trichothecene deoxynivalenol (DON). Although the infection mainly affects the grain yield, little is known about its impact on grain structural and biochemical properties. Yet, such information is instrumental to characterize the facets of resistance in the grains. After artificial inoculation of six barley cultivars with FG in a 2 years field test, different levels of symptoms on spikes, of colonisation of grains and of DON content were observed. The infections caused a reduction in grain weight and an average decrease of 10% of the β-glucan content in grains, indicating alterations of grain filling, composition and structure. According to our results, we postulate the presence of two distinct resistance mechanisms in the grain, tolerance to grain filling despite infection as well as the inhibition of mycotoxin accumulation. Differently to wheat, in barley, type IV resistance (tolerance of the grain to infection) is directly linked with type III resistance (resistance against kernel infection). The resistance against toxin accumulation (named type V resistance in wheat) appeared to be independent to all other resistance types. Generally, the resistance was significantly influenced by the environment and by genotype x environment interactions explaining the generally weak stability of resistance in barley. Interestingly, a significant and inverse relationship between DON contamination and β-glucan content in grains suggests that high β-glucan content in grains contributes to type V resistance.