Response of climate-growth relationships and water use efficiency to thinning in a Pinus nigra afforestation     

Darío Martín-Benito  Miren Del Río  Ingo Heinrich  Gerhard Helle  Isabel Cañellas 《Forest Ecology and Management》2010

Thinning is the main forestry measure to increase tree growth by reducing stand tree density and competition for resources. A thinning experiment was established in 1993 on a 32-year-old Pinus nigra Arn. stand in central Spain. The response of growth, climate-growth relationships and intrinsic water use efficiency (WUEi) to a stand density reduction were compared between moderate thinned plots and a control plot by a combined analysis of basal area increments (BAI), and C and O stable isotope ratios (δ¹³C_c and δ¹⁸O_c). BAI in the control plot showed a decreasing trend that was avoided by thinning in the thinned plot. Thinning also partially buffered tree-ring response to climate and trees were less sensitive to precipitation although more sensitive to temperature. Δ¹³C_c in the thinned plot was not modified indicating that stomatal conductance (g) and photosynthetic capacity (A) did not change or change in the same direction. However, δ¹⁸O_c decreased in the control plot (unrelated to δ¹⁸O of precipitation) but not in the thinned plot, suggesting a relative increase of temperature and irradiance and/or a decrease of air humidity after reducing the density consistent with an increase in A, g and BAI. As WUEi did not increase in the thinned plot, faster growth in this plot was caused by higher abundance of resources per tree. The trend of WUEi in both plots indicated low-moderate CO₂-induced improvements. Thinning might be a useful adaptation measure against climate change in these plantations reducing their vulnerability to droughts. However, because WUEi was not affected, the positive growth response might be limited if droughts and warming continue and certain thresholds are exceeded.  相似文献   

Identification of enterodiol as a masker for caffeine bitterness by using a pharmacophore model based on structural analogues of homoeriodictyol     

Ley JP  Dessoy M  Paetz S  Blings M  Hoffmann-Lücke P  Reichelt KV  Krammer GE  Pienkny S  Brandt W  Wessjohann L 《Journal of agricultural and food chemistry》2012,60(25):6303-6311

Starting from previous structure-activity relationship studies of taste modifiers based on homoeriodictyol, dihydrochalcones, deoxybenzoins, and trans-3-hydroxyflavones as obvious analogues were investigated for their masking effect against caffeine. The most active compounds of the newly investigated taste modifiers were phloretin, the related dihydrochalcones 3-methoxy-2',4,4'-trihydroxydihydrochalcone and 2',4-dihydroxy-3-methoxydihydrochalcone, and the deoxybenzoin 2-(4-hydroxy-3-methoxyphenyl)-1-(4-hydroxyphenyl)ethanone. Starting with the whole set of compounds showing activity >22%, a (Q)SAR pharmacophore model for maskers of caffeine bitterness was calculated to explain the structural requirements. After docking of the pharmacophore into a structural model of the broadly tuned bitter receptor hTAS2R10 and docking of enterolactone and enterodiol as only very weakly related structures, it was possible to predict qualitatively their modulating activity. Enterodiol (25 mg L(-1)) reduced the bitterness of the 500 mg L(-1) caffeine solution by about 30%, whereas enterolactone showed no masking but a slight bitter-enhancing effect.  相似文献   

Nuclear magnetic resonance spectroscopy and chemometrics to identify pine nuts that cause taste disturbance     

Kobler H  Monakhova YB  Kuballa T  Tschiersch C  Vancutsem J  Thielert G  Mohring A  Lachenmeier DW 《Journal of agricultural and food chemistry》2011,59(13):6877-6881

Nontargeted 400 MHz (13)C and (1)H nuclear magnetic resonance (NMR) spectroscopy was used in the context of food surveillance to reveal Pinus species whose nuts cause taste disturbance following their consumption, the so-called pine nut syndrome (PNS). Using principal component analysis, three groups of pine nuts were distinguished. PNS-causing products were found in only one of the groups, which however also included some normal products. Sensory analysis was still required to confirm PNS, but NMR allowed the sorting of 53% of 57 samples, which belong to the two groups not containing PNS species. Furthermore, soft independent modeling of class analogy was able to classify the samples between the three groups. NMR spectroscopy was judged as suitable for the screening of pine nuts for PNS. This process may be advantageous as a means of importation control that will allow the identification of samples suitable for direct clearance and those that require further sensory analysis.  相似文献   

Carry-over of thermophilic Campylobacter spp. between sequential and adjacent poultry flocks     

Thomas Alter  Rita Margarete Weber  Ahmad Hamedy  Gerhard Glünder 《Veterinary microbiology》2011,147(1-2):90-95

Nineteen flocks of four poultry species were monitored at a veterinary field station to investigate the distribution and spread of Campylobacter genotypes between sequential and adjacent flocks. Caecal and liver samples were obtained at frequent intervals from birds of all flocks and examined for Campylobacter. Amplified fragment length polymorphism (AFLP) analysis was performed to genotype Campylobacter isolates. Of the 1643 caecal and liver samples investigated, 452 (27.5%) caecal samples and 11 (0.7%) liver samples contained Campylobacter. Of the caecal isolates 76.3% were identified as Campylobacter jejuni and 23.7% were identified as Campylobacter coli. Poultry flocks were largely colonized by more than one AFLP type and an intense exchange of Campylobacter genotypes between different poultry flocks occurred. These findings indicate that multiple genotypes can constitute the Campylobacter population within single poultry flocks, hinting to different sources of exposure and/or genetic drifts within the Campylobacter population. Nevertheless, in most flocks single Campylobacter genotypes predominated. Some strains superseded others resulting in colonization by successive Campylobacter genotypes during the observation period. In conclusion, the data demonstrate that the large genetic diversity of Campylobacter must be considered in epidemiological evaluations and microbial risk assessments of Campylobacter in poultry.  相似文献   

Efficacy of adding ramipril (VAsotop) to the combination of furosemide (Lasix) and pimobendan (VEtmedin) in dogs with mitral valve degeneration: The VALVE trial     

Gerhard Wess  Jan-Gerd Kresken  Ralph Wendt  Juliane Gaugele  Markus Killich  Lisa Keller  Julia Simak  Peter Holler  Alexander Bauer  Helmut Küchenhof  Tony Glaus 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2020,34(6):2232-2241

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Left ventricular M-mode prediction intervals in 7651 dogs: Population-wide and selected breed-specific values     

Lilith Carla Esser  Martin Borkovec  Alexander Bauer  Jens Häggström  Gerhard Wess 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2020,34(6):2242-2252

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Temporal changes in clinical and radiographic variables in dogs with preclinical myxomatous mitral valve disease: The EPIC study     

Adrian Boswood  Sonya G. Gordon  Jens Häggström  Martin Vanselow  Gerhard Wess  Rebecca L. Stepien  Mark A. Oyama  Bruce W. Keene  John Bonagura  Kristin A. MacDonald  Mark Patteson  Sarah Smith  Philip R. Fox  Karen Sanderson  Richard Woolley  Viktor Szatmári  Pierre Menaut  Whitney M. Church  M. Lynne O'Sullivan  Jean-Philippe Jaudon  Jan-Gerd Kresken  John Rush  Kirstie A. Barrett  Steven L. Rosenthal  Ashley B. Saunders  Ingrid Ljungvall  Michael Deinert  Eric Bomassi  Amara H. Estrada  Maria J. Fernandez Del Palacio  N. Sydney Moise  Jonathan A. Abbott  Yoko Fujii  Alan Spier  Michael W. Luethy  Roberto A. Santilli  Masami Uechi  Anna Tidholm  Christoph Schummer  Philip Watson 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2020,34(3):1108-1118

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Grundzüge standortgerechter Verfahren der Mineraldüngeranwendung auf der Grundlage von Feldversuchsergebnissen     

Hermann Ansorge  Hans Görlitz  Gerhard Specht  Peter Kundler 《Archives of Agronomy and Soil Science》2013,59(5-6):525-535

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Beeinflussung von Qualitätsmerkmalen durch Pflanzenzüchtung — Möglichkeiten und Probleme     

Gerhard Röbbelen 《Plant foods for human nutrition (Dordrecht, Netherlands)》1976,26(1-3):149-166

Zusammenfassung Der steigende Bedarf an Nahrungs- und Futtermitteln, vermehrt durch erhöhte Ansprüche, löste in den letzten Jahrzehnten verstärkte Bemühungen zur züchterischen Qualitätsverbesserung pflanzlicher Grundprodukte aus. Diese Entwicklung ist grundsätzlich keineswegs neu. Bereits aus den Anfängen einer bewußten Pflanzenzüchtung lassen sich dafür zahlreiche Beispiele anführen. Neu aber ist die züchterische Effizienz, mit der heute die Verbesserung von sogenannten inneren Qualitätsmerkmalen betrieben werden kann. Das beruht einerseits auf dem enormen Fortschritt der analytischen Technik, der die Durchmusterung riesiger Anzahlen von Pflanzenmustern in kurzer Zeit mit niedrigen Kosten und sehr kleinen Probenmengen (oft nur Teilen eines Samens) ermöglichte. Andererseits stellen große internationale Sammlungen im Netzwerk der Genbanken solchen Untersuchungen eine bis dahin kaum erreichbare Vielfalt an Genotypen zur Verfügung. Diese kann durch laufende Verbesserungen in der Kunst der experimentellen Mutationsauslösung zunehmend verbreitert werden. Nicht unwichtig sind für den Pflanzenzüchter in vielen Fällen neue Erkenntnisse über beteiligte stoffwechselreaktionen oder Biogeneseschritte der qualitätsbestimmenden Stoffgruppen, wenngleich hier für besser gezielte züchterische Eingriffe noch viel zu tun bleibt. Zuchtmethodisch ist neben anderen Problemen die Frage zu klären, ob der zumeist unzureichende Erfolg der z.Zt. vorwiegend verwendeten drastischen, einfach vererbten Qualitätsmutanten, wie deropaque-Mutante vom Mais oder der Hiproly-Mutante von Gerste, auf eben dieser qualitativen Natur beruht und man sich als Züchter auf lange Sicht nicht mehr auf quantitative, polygen bedingte Merkmalsänderungen stützen sollte. Unentbehrlich schließlich sind für die Qualitätszüchtung langfristig vorausbestimmte Züchtungsprioritäten, die auch noch nach Abschluß der Zuchtarbeiten, d.h. 10–15 Jahren, Gültigkeit haben und die den neuen Sorten dann einen ausreichend breiten Anbau und Markt sicherstellen. Bei den sich laufend erweiternden Erkenntnissen über den Komplex Ernährung sowie den oft rapiden marktwirtschaftlichen Fluktuationen ist diese Grundforderung einer erfolgreichen Qualitätszüchtung heute nicht immer erfüllt. Dementsprechend spielt in der landwirtschaftlichen Erzeugung nach wie vor die Quantität die überragende und die innere Qualität der erzeugten Produkte gewöhnlich nur eine untergeordnete Rolle.

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Manipulations of quality traits by plant breeding — Challenge and problems

Polyploidy, giant growth, and allometric development contributed to the improvement of nutritive quality in cultivated plants since their first origin. But only recently, rapid progress in biochemical analytical techniques, in the evaluation and induction of genetic variability, and in the understanding of underlying physiological processes, gave way to an enormous increase in intensity and efficiency in the field of breeding for quality. The specific methodology of this kind of selection, however, still lacks much essential knowledge and the same holds true for nutritional data, which are basic for the formulation of valid breeding aims.

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Vortrag, gehalten auf der gemeinsamen Tagung der Internationalen Vereinigung zur Erforschung der Qualität von Nahrungspflanzen (CIQ) und der Deutschen Gesellschaft für Qualitätsforschung (Pflanzliche Nahrungsmittel) e.V. (DGQ) in Wädenswil/Schweiz am 7. Oktober 1975.  相似文献   

Soil heterogeneity at the field scale: a challenge for precision crop protection     

Stefan Patzold  Franz Michael Mertens  Ludger Bornemann  Britta Koleczek  Jonas Franke  Hannes Feilhauer  Gerhard Welp 《Precision Agriculture》2008,9(6):367-390

Crop protection seldom takes into account soil heterogeneity at the field scale. Yet, variable site characteristics affect the incidence of pests as well as the efficacy and fate of pesticides in soil. This article reviews crucial starting points for incorporating soil information into precision crop protection (PCP). At present, the lack of adequate field maps is a major drawback. Conventional soil analyses are too expensive to capture soil heterogeneity at the field scale with the required spatial resolution. Therefore, we discuss alternative procedures exemplified by our own results concerning (i) minimally and non-invasive sensor techniques for the estimation of soil properties, (ii) the evidence of soil heterogeneity with respect to PCP, and (iii) current possibilities for incorporation of high resolution soil information into crop protection decisions. Soil organic carbon (SOC) and soil texture are extremely interesting for PCP. Their determination with minimally invasive techniques requires the sampling of soils, because the sensors must be used in the laboratory. However, this technique delivers precise information at low cost. We accurately determined SOC in the near-infrared. In the mid-infrared, texture and lime content were also exactly quantified. Non-invasive sensors require less effort. The airborne HyMap sensor was suitable for the detection of variability in SOC at high resolution, thus promising further progress regarding SOC data acquisition from bare soil. The apparent electrical conductivity as measured by an EM38 sensor was shown to be a suitable proxy for soil texture and layering. A survey of arable fields near Bonn (Germany) revealed widespread within-field heterogeneity of texture-related ECa, SOC and other characteristics. Maps of herbicide sorption and application rate were derived from sensor data, showing that optimal herbicide dosage is strongly governed by soil variability. A phytoassay with isoproturon confirmed the reliability of spatially varied herbicide application rates. Mapping areas with an enhanced leaching risk within fields allows them to be kept free of pesticides with related regulatory restrictions. We conclude that the use of information on soil heterogeneity within the concept of PCP is beneficial, both economically and ecologically.  相似文献