A theory relating focal epidemics to crop-weed interactions     

Frantzen J  Müller-Schärer H 《Phytopathology》1998,88(3):180-184

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Detection of Helicobacter-like Bacteria in Porcine Gastric Biopsy Samples by Amplification of 16S rRNA,ureB, vacA and cagA Genes by PCR     

Utriainen  M.  Hänninen  M.-L. 《Veterinary research communications》1998,22(6):373-384

Preliminary evidence for the presence of Helicobacter-like bacteria was sought in 395 porcine gastric samples by a urease test. Of the samples, 37% (146/395) were urease-positive and 82% (82/100) of the Gram-stained urease-positive samples showed large, tightly spiralled organisms. Several methods were applied to culture the organisms but isolation was unsuccessful, contaminant organisms being considered to be one of the major problems. PCR with Helicobacter genus-specific primers for 16S rRNA and ureB genes, and primers for H. pylori vacA and cagA genes were tested with 102 urease-positive biopsy samples. The PCR results showed some evidence for the presence of the urease and the vacA genes in porcine Helicobacter-like bacteria and raises the possibility of pathogenicity by these organisms.  相似文献   

Über die Veränderungen der Sorptionseigenschaften von Wurzeln zweier Pflanzenarten während der Verrottung     

Anton Kullmann  Käte Koepke 《Archives of Agronomy and Soil Science》2013,59(4):285-297

Die Steigerung der naturalen Erträge unserer Kulturpflanzen ist gegenwärtig kein wissenschaftlicher Arbeitsgegenstand der produktionsorientierten landwirtschaftlichen Forschung. Es bestehen häufig Bedenken, daß mit einer zunehmenden Ertragshöhe unerwünschte Wirkungen auf die Umwelt verbunden sind.

An ausgewählten Beispielen wird dargelegt, daß es zum einen nicht möglich ist, aus der Ertragshöhe oder den Ertragssteigerungen pauschal auf negative Umweltwirkungen der ackerbaulichen Produktion zu schließen. Zudem wird diskutiert, welche Bedeutung die Steigerung der Erträge von Kulturpflanzen für die Sicherung der technologischen, aber auch der ökologischen Ansprüche hat.

Ein Rückgang der Forschungs‐ und Publikationsleistungen zu Anbauverfahren bzw. dem Ertragsmanagement wird für die letzten Jahre dargelegt und dessen Bedeutung für die wissenschaftlichen Arbeiten der landwirtschaftlichen Produktion erörtert.  相似文献   

ASAVA oncology presentations a highlight for Cairns 2003     

Jouko Koppinen 《Australian veterinary journal》2003,81(3):121-121

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Diameter growth of Scots pine (Pinus sylvestris) trees grown at elevated temperature and carbon dioxide concentration under boreal conditions     

Peltola H  Kilpeläinen A  Kellomäki S 《Tree physiology》2002,22(14):963-972

We investigated the impacts of elevated temperature and carbon dioxide concentration ([CO2]) on diameter growth of Scots pine (Pinus sylvestris L.), aged about 20 years, grown with a low nitrogen supply in closed chambers at (i) ambient temperature and [CO2] (AT+AC), (ii) ambient temperature and elevated [CO2] (AT+EC), (iii) elevated temperature and ambient [CO2] (ET+AC), and (iv). elevated temperature and [CO2] (ET+EC). Each treatment was replicated four times. Diameter growth was monitored with a band dendrograph at 15-min intervals throughout the growing seasons of 1997, 1998 and 1999. Over the monitoring period, diameter growth began 2-3 weeks earlier in trees in the ET+EC and ET+AC chambers than in trees in the AT+AC and AT+EC chambers. However, the cessation of growth occurred about a week later in trees in the ET+EC, ET+AC and AT+EC chambers compared with the AT+AC chambers. The duration of the growing season was 115 and 108 days in the ET+EC and ET+AC chambers, respectively, and 95 and 84 days in the AT+EC and AT+AC chambers, respectively. The ET+AC and ET+EC treatments enhanced diameter growth most early in the growing season, whereas in trees in the AT+AC and AT+EC treatments diameter growth rate was highest in the middle of the growing season. Diameter growth rate leveled off more slowly in trees in the ET+EC and AT+EC treatments than in the other treatments. The growth response to elevated T, elevated [CO2] or both decreased with time and it was less than the maximum observed in other studies for small seedlings and under optimal growth conditions. Nevertheless, cumulative diameter growth for the 3-year period was 67% greater in trees in the ET+EC treatment, and 57 and 26% greater in trees in the AT+EC and ET+AC treatments, respectively, compared with trees in the AT+AC treatment. Over the 3 years, [CO2] had a statistically significant (P < 0.10) effect on both absolute and relative diameter growth, but the interaction between [CO2] and temperature was not significant.  相似文献   

Köderscheu bei Wühlmäusen (Microtinae)     

Prof. Dr. W. Bäumler 《Journal of pest science》1992,65(4):65-67

Zusammmenfassung Im Rahmen der amtlich vorgeschriebenen Prüfung von Rodentiziden wurde beobachtet, daß Jungtiere der Rötelmaus und der Erdmaus, die noch im Familienverband mit ihren Eltern leben, besonders häufig köderscheu werden. Offensichtlich ermöglicht das Lernverhalten der Jungtiere bei der Nahrungsaufnahme der Eltern ein allmähliches Kennenlernen geeigneter oder ungeeigneter Nahrung. Die Jungtiere nehmen häufig feine Nahrungspartikel von den Lippen, insbesondere des Muttertieres auf. Somit können sie allmählich auch Erfahrungen über die Wirkung von akut wirksamen Rodentiziden sammeln, ohne selbst eine letale Dosis aufzunehmen. Hinweise über eine weitergehende Informationsübertragung, die zur Köderscheu führen kann, wurden nicht gefunden.

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Bait shyness of voles

Some rodents like the Common Vole (Microtus agrestis) and the Bank Vole (Clethrionomys glareolus) can cause severe damages in forest cultivations and orchards by gnawing roots and bark of the trees. Among other countermeasures zinc phosphide baits are used to prevent losses. However, some individuals get bait shy against the used acute poison usually. It was observed in some choice tests that young voles can learn very easily from her parents to avoid baits which contain an acute poison. The nestlings are licking the lips especially of her mother during food consumption. In this way they can get some information about palatable and non-palatable food items. Young voles living in her family can become bait shy rapidly during the learning and food imprinting process.

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Mit einer Tabelle  相似文献   

Sekrete und Delta-16-Steroide als Lockmittel für die Rötelmaus (Clethrionomys glareolus)     

Prof. Dr. W. Bäumler  I. Haag 《Journal of pest science》1989,62(3):55-59

Zusammenfassung Lebendfallen, die Nestmaterial oder Ausscheidungen von Rötelmäusen enthielten, wurden im Freiland von Artgenossen signifikant häufiger besucht als nicht-kontaminierte Fallen. Die Untersuchungen wurden im Spätsommer und Herbst in den Jahren 1986 und 1987 in Forstkulturen durchgeführt. In den Monaten August bis Oktober wurden Fallen, die kontaminierte Einstreu von Artgenossen enthielten, bevorzugt, in den Monaten November und Dezember Fallen mit Nestgeruch.Von den beiden Verbindungen 16-(5-alpha)-androsten-3-on (Androsten-on) und 16-(5-alpha)-androsten-3-alpha-ol (Androsten-ol) wurde die letztere signifikant von der Rötelmaus bevorzugt.

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Secretions and Delta-16-steroids as attractants for Bank Voles (Clethrionomys glareolus)

Bank Voles (Clethrionomys glareolus) preferred significantly live traps containing bedding or nesting material contaminated by conspecifics in comparision to clean traps (=control). The tests were conducted in forest cultivations in late summer and autumn of 1986 and 1987. In both years at the begin in August the traps contaminated with urin of conspecifics were most attractive. Females were significantly more frequently caught in traps contaminated by conspecific males and vice versa males visited preferably traps with bedding material of females. Later during October and November traps with nest odour were preferred by both sexes.It was assumed that derivatives of hormones could act as pheromones. Both compounds 16-(5-alpha)-androsten-3-one and 16-(5-alpha)-androsten-3-alpha-ol were tested in field plots. The latter was significantly preferred by Bank Voles but not by other species.

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Mit 7 Abbildungen und einer Tabelle  相似文献   

Auftreten vonThomasiniana crataegi Barnes (Weiβdornzweiggallmücke) an Weiβdorn     

K. Küthe  K. Krämer 《Journal of pest science》1959,32(3):40-41

Ohne Zusammenfassung  相似文献   

Über die Rolle der Biogeozönose im Wurzelbereich von Waldbäumen     

H. Blaschke  W. Bäumler 《European Journal of Forest Research》1986,105(1):122-130

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Age effects on Norway spruce (Picea abies) susceptibility to ozone uptake: a novel approach relating stress avoidance to defense     

Wieser G  Tegischer K  Tausz M  Häberle KH  Grams TE  Matyssek R 《Tree physiology》2002,22(8):583-590

Cumulative ozone (O3) uptake and O3 flux were related to physiological, morphological and biochemical characteristics of Norway spruce (Picea abies (L.) Karst.) trees of different ages. Under ambient CO2 conditions, photosynthetic capacity (Amax) declined in mature trees when cumulative O3 uptake into needles, which provides a measure of effective O3 dose, exceeded 21 mmol m-2 of total needle surface area. A comparable decline in Amax of seedlings occurred when cumulative O(3) uptake was only 4.5 mmol m-2. The threshold O3 flux causing a significant decline in Amax ranged between 2.14 and 2.45 nmol m-2 s-1 in mature trees and seedlings subjected to exposure periods of > or = 70 and > or = 23 days, respectively. The greater O3 sensitivity of young trees compared with mature trees was associated with needle morphology. Biomass of a 100-needle sample increased significantly with tree age, whereas a negative correlation was found for specific leaf area, these changes parallel those observed during differentiation from shade-type to sun-type needles with tree ontogeny. Age-dependent changes in leaf morphology were related to changes in detoxification capacity, with area-based concentrations of ascorbate increasing during tree ontogeny. These findings indicate that the extent of O3-induced injury is related to the ratio of potentially available antioxidants to O3 influx. Because this ratio, when calculated for ascorbate, increased with tree age, we conclude that the ratio may serve as an empirical basis for characterizing age-related differences in tree responses to O3.  相似文献