Ertragsstrukturelle Untersuchungen an der Wintergerste — ein Vorschlag zur Aufstellung einer Ertragsfunktion     

Norbert Makowski 《Archives of Agronomy and Soil Science》2013,59(10):891-897

  相似文献   

Plant availability of isotopically exchangeable and isotopically nonexchangeable phosphate in soils     

Ricardo Cabeza  Bernd Steingrobe  Wilhelm Römer  Norbert Claassen 《植物养料与土壤学杂志》2013,176(5):688-695

Isotopically exchangeable P (IEP) is usually considered to be completely plant‐available and the major source of P for plant uptake. The aim of the present study is to test whether plants can, besides IEP, also use non‐IEP and if part of the IEP has an equilibrium concentration in soil solution which is below the minimum concentration, C_Lmin, and can therefore not be taken up by plants. A pot experiment was carried out with maize for two years on two soils, an acid sandy and a neutral loamy soil, either without P fertilizer or fertilized with ten P sources of different solubility. Throughout both years of the study, pots were kept moist either without plants or planted twice with maize (Zea mays L., cv. Athletico). At the end of the experiment, plant P uptake, P concentration in the soil solution (C_L), and P accessible to isotopic exchange within 5 d (E_5d) were measured. Plant growth decreased the E_5d which was about equal to P uptake by maize for most treatments in the acid soil. But for some treatments, i.e., five in the acid and eight in the neutral soil, P uptake was up to 50% larger than the decrease of E_5d, indicating that plants had, besides IEP, also used P from non‐IEP sources. At adequate P supply, both soils had an E_5d of about 100 mg P (kg soil)^–1, but about 30 to 40 mg kg^–1 of this IEP had an equilibrium P concentration in the soil solution below C_Lmin of 0.1 μmol L^–1 at which P would actually not be plant‐available. This study shows that plants take up P mainly from IEP, but not the whole IEP is plant‐available. Furthermore, plants may also use P from non‐IEP sources.  相似文献   

Impact of the N-terminal amino acid on the formation of pyrazines from peptides in Maillard model systems     

Van Lancker F  Adams A  De Kimpe N 《Journal of agricultural and food chemistry》2012,60(18):4697-4708

Only a minor part of Maillard reaction studies in the literature focused on the reaction between carbohydrates and peptides. Therefore, in continuation of a previous study in which the influence of the peptide C-terminal amino acid was investigated, this study focused on the influence of the peptide N-terminal amino acid on the production of pyrazines in model reactions of glucose, methylglyoxal, or glyoxal. Nine different dipeptides and three tripeptides were selected. It was shown that the structure of the N-terminal amino acid is determinative for the overall pyrazine production. Especially, the production of 2,5(6)-dimethylpyrazine and trimethylpyrazine was low in the case of proline, valine, or leucine at the N-terminus, whereas it was very high for glycine, alanine, or serine. In contrast to the alkyl-substituted pyrazines, unsubstituted pyrazine was always produced more in the case of experiments with free amino acids. It is clear that different mechanisms must be responsible for this observation. This study clearly illustrates the capability of peptides to produce flavor compounds such as pyrazines.  相似文献   

Species-specific and generic biomass equations for seedlings and saplings of European tree species     

Peter Annighöfer  Aitor Ameztegui  Christian Ammer  Philippe Balandier  Norbert Bartsch  Andreas Bolte  Lluís Coll  Catherine Collet  Jörg Ewald  Nico Frischbier  Tsegay Gebereyesus  Josephine Haase  Tobias Hamm  Bastian Hirschfelder  Franka Huth  Gerald Kändler  Anja Kahl  Heike Kawaletz  Christian Kuehne  André Lacointe  Na Lin  Magnus Löf  Philippe Malagoli  André Marquier  Sandra Müller  Susanne Promberger  Damien Provendier  Heinz Röhle  Jate Sathornkich  Peter Schall  Michael Scherer-Lorenzen  Jens Schröder  Carolin Seele  Johannes Weidig  Christian Wirth  Heino Wolf  Jörg Wollmerstädt  Martina Mund 《European Journal of Forest Research》2016,135(2):313-329

  相似文献   

The relationship between clinical signs of respiratory system disorders and lung lesions at slaughter in veal calves     

Leruste H  Brscic M  Heutinck LF  Visser EK  Wolthuis-Fillerup M  Bokkers EA  Stockhofe-Zurwieden N  Cozzi G  Gottardo F  Lensink BJ  van Reenen CG 《Preventive veterinary medicine》2012,105(1-2):93-100

The presence and severity of lung lesions recorded post-mortem is commonly used as an indicator to assess the prevalence of respiratory problems in batches of bovines. In the context of a welfare monitoring based on on-farm measures, the recording of clinical signs on calves at the farm would be more convenient than the recording of lung lesions at slaughter. The aim of the present study was to investigate the relationship between clinical respiratory signs at farm and post-mortem analyses of lung lesions observed at slaughter in veal calves. If clinical signs were a good predictor of lung lesions it could be possible to integrate only those measures in a welfare monitoring system. One-hundred-and-seventy-four batches of calves were observed 3 times: at 3 and 13 weeks after arrival of the calves at the unit and at 2 weeks before slaughter. For each batch a maximum of 300 calves was observed and the proportions of calves showing abnormal breathing, nasal discharge and coughing were recorded. Post-mortem inspection was carried out on a sample of lungs belonging to calves from the observed batches. Each examined lung was classified according to a 4-point scale for pneumonia from healthy lung (score 0) to severe lesions (score 3). The clinical signs recorded infra vitam were significantly correlated with moderate and severe lung lesions for observations at 13 weeks and 2 weeks before slaughter and the level of the correlation was highly variable (r(sp) from 0.16 to 0.40). Receiver operating characteristic (ROC) curves were created and the area under the curves showed that batches with a high proportion of lungs with moderate or severe lesions could not be accurately detected by the three clinical signs of respiratory disorders. These results suggest that both clinical signs and post-mortem inspection of lung lesions must be included in a welfare monitoring schemes for veal calves.  相似文献   

Cell tropism of Staphylococcus aureus in bovine mammary gland cell cultures.     

A Lammers  P J Nuijten  E Kruijt  N Stockhofe-Zurwieden  U Vecht  H E Smith  F G van Zijderveld 《Veterinary microbiology》1999,67(2):77-89

Staphylococcus aureus is one of the most important pathogens of the bovine mammary gland. The interaction of S. aureus with cells of the bovine mammary gland is considered to play an essential role in the pathogenesis. In this study, we identified a new target cell for S. aureus adhesion and invasion. For that purpose, cells which compose the alveoli of the mammary gland were cultured. In these cultures, two morphologically different cell types, elongated and cubic cells, were observed. Adhesion and invasion of S. aureus was studied using microscopical and microbiological methods. S. aureus adhered specifically and in large numbers (about 300 bacteria/cell) to the elongated cell type. No adhesion to the cubic cell type was observed. In addition, bacteria were also found intracellularly in the elongated cells, and enclosed in membrane vesicles. Adhesion and invasion were time dependent and reached maximum levels after 4 h. Invasion was strongly reduced by staurosporine and genistein. The newly identified target cell was further characterized.  相似文献   

Canopy composition as a measure to identify patterns of nutrient input in a mixed European beech and Norway spruce forest in central Europe     

S. Mohammad Hojjati  Anna Hagen-Thorn  Norbert P. Lamersdorf 《European Journal of Forest Research》2009,128(1):13-25

The influence of canopy composition on litterfall and throughfall was investigated in a mixed spruce beech forest in central Germany. We hypothesised that different parts of the mixed canopy created distinct patterns of element inputs via litterfall and throughfall. The investigation was carried out in two plots, representing the most contrasting cases of mixed forests: a stand greatly dominated by spruce (SDP) and a stand greatly dominated by beech (BDP). The canopies of the two plots were classified in four categories: pure beech, pure spruce, mixed canopy and gap. Amounts of throughfall water were lower and major element fluxes were higher under spruce than under beech in both plots, indicating that the nutrient inputs under the canopies of individual trees are driven by species-specific properties of the canopies and are quite independent of the degree of admixture. With the exception of K⁺, mixed canopies showed intermediate element inputs via throughfall, compared with pure canopy classes. The K⁺ input was significantly greater under mixed canopies, and these differences were more pronounced in the SDP than in the BDP. Results suggest that individual spruce trees in the BDP induce greater spatial heterogeneity of throughfall input than individual beech trees in the SDP. Nutrient inputs via foliar litterfall were similar among the different canopy classes, but the Mg input was lower under spruce canopy. This effect was balanced by higher Mg input via spruce throughfall. In our study, throughfall was the main source of heterogeneity in nutrient inputs, while foliar litterfall had a homogenising effect.  相似文献   

“近自然林”——一种理念的起源与传播   总被引：1，自引：0，他引：1  

张德顺  李秀芬  Norbert Weber 《山东林业科技》2009,39(2):102-105

欧洲林业在走过了大面积纯林种植后,出现了地力衰退、病虫害频发、系统稳定性差等种种弊端,人们逐渐认识到遵循自然规律,以自然的力量改造、经营森林,将会使森林产生最大的生态效益、经济效益和社会效益。1886年,德国慕尼黑工业大学造林学教授卡尔嘎耶（KarlGayer）在其著作“gesmifchte wald（历史森林）--Jeine begriindung und pflege（没有培育和养护的林业）”一书中写到“我们师法自然而不应该过于远离大自然的规律,  相似文献   

德国中部Soiling云杉-山毛榉混交林冠层组成对土壤CO2排放的影响     

Seyed Mohammd Hojjati  Norbert P. Lamersdorf 《林业研究》2010,21(4):461-464

It was hypothesized that soil respiration can be affected by canopy composition. Hence, admixture of trees as a common forest management practice may cause significant change in the carbon cycling. This study was conducted in a mixed spruce-beech stand at Solling forest in central Germany to investigate the effect of canopy composition on soil respiration. The canopy cover was classified in four major canopy classes (pure beech, pure spruce, mixed and gap), and the area under each canopy class was identified as a sub-plot. Soil respiration in each sub-plot (n=4) was measured monthly from Jun 2005 to July 2006. Results show significant difference in annual soil respiration between the beech (359 g·m⁻²·a⁻¹ C) and gap (211 g·m⁻²·a⁻¹ C) sub-plots. The estimation of the total below-ground carbon allocation (TBCA) based on a model given by Raich and Nadelhoffer revealed considerably higher root CO₂ production in the beech sub-plot (231 g·m⁻²·a⁻¹ C) compare to the gap sub-plot (51 g·m⁻²·a⁻¹ C). The contribution of the root respiration to the total soil respiration was higher in the soil under the beech canopy (59%) compared with the soil in the gap (29%). The findings suggested that the condition under the beech canopy may cause more desirable micro-site for autotrophic respiration and consequently higher CO₂ release into the atmosphere.  相似文献   

Impact of Stolbur Phytoplasmas on Potato Tuber Texture and Sugar Content of Selected Potato Cultivars     

Kerstin Lindner  Norbert U. Haase  Marinela Roman  Erich Seemüller 《Potato Research》2011,54(3):267-282

Potato stolbur is a phytoplasmal disease that seriously affects yield and tuber quality in South Eastern Europe, Russia and the Mediterranean areas. In 2007 and 2008, field experiments were carried out to determine stolbur resistance of processing potato cultivars at Sannicolau Mare (Romania) by determining consistency and concentration of reducing sugars (fructose and glucose), sucrose and phytoplasmas in potato tubers. In both years, non-symptomatic potato tubers showed sucrose levels in the range of 3,000 mg kg⁻¹ fresh weight (FW). In contrast, sucrose concentrations were up to 11,820 mg kg⁻¹ FW in 2007 and 19,560 mg kg⁻¹ FW in 2008 in tubers showing severe symptoms. These high values severely affect suitability of tubers for processing as sucrose serves as substrate for the formation of reducing sugars that are the limiting factor in fried potato production for Maillard-related discolouration. The cultivars examined differed considerably in susceptibility to stolbur disease. Whereas cvs. ‘Courage’ and ‘Lady Rosetta’ showed high numbers of diseased tubers and high sucrose concentrations, ‘Lady Claire’ had a lower incidence of symptomatic tubers and lower sucrose concentrations. However, fully resistant cultivars were not observed. Across all cultivars examined, phytoplasmal concentration was significantly higher in symptomatic tubers than in non-symptomatic ones.  相似文献