Major gene resistance in Brassica napus (oilseed rape) is overcome by changes in virulence of populations of Leptosphaeria maculans in France and Australia     

Susan J. Sprague  Marie-Hélène Balesdent  Hortense Brun  Helen L. Hayden  Stephen J. Marcroft  Xavier Pinochet  Thierry Rouxel  Barbara J. Howlett 《European journal of plant pathology / European Foundation for Plant Pathology》2006,114(1):33-40

Resistance of Brassica napus (oilseed rape, canola) conferred by three different major resistance genes has been overcome by changes in virulence of Leptosphaeria maculans populations in France and Australia. In South Australia where B. napus cultivars with major gene resistance derived from Brassica rapa ssp. sylvestris were grown extensively, resistance was rendered ineffective within 3 years of commercial release of the cultivar. Disease severity was higher on cultivars with sylvestris-derived resistance than cultivars with polygenic resistance. This Australian situation is compared to that in France, where resistance conferred by the Rlm1 gene was overcome nation-wide in 5 years under commercial cropping practices, and also where a source of resistance introgressed into B. napus from B. juncea was rendered inefficient in 3 years in experimental field plots near Rennes.  相似文献   

An Aqueous Extract of the Dry Mycelium of Penicillium chrysogenum Induces Resistance in Several Crops under Controlled and Field Conditions     

Barbara Thuerig  Andres Binder  Thomas Boller  Urs Guyer  Sonia Jiménez  Christina Rentsch  Lucius Tamm 《European journal of plant pathology / European Foundation for Plant Pathology》2006,114(2):185-197

We have examined the effect of Pen, an aqueous extract of the dry mycelium of Penicillium chrysogenum, on plant–pathogen interactions. Pen controlled a broad range of pathogens on several crop plants under greenhouse and field conditions. Pen protected grapevine from downy and powdery mildew (caused by Plasmopara viticola and Uncinula necator), tomato from early blight (caused by Phytophthora infestans), onion from downy mildew (Peronospora destructor) and apple trees from apple scab (caused by Venturia inaequalis) to a similar extent as fungicides such as copper and sulphur or well-known inducers such as benzothiadiazole or β-aminobutyric acid. Pen had no major direct fungicidal effect and is thus supposed to protect plants by activating their defense mechanisms. The raw material for extraction of Pen was available in constant quality, a prerequisite for commercial application. Under certain conditions, Pen caused phytotoxic side effects. The symptoms mostly consisted of small necrotic spots or, more rarely, of larger necrotic areas. The development of the symptoms was dependent on several parameters, including concentration of Pen, the number of applications, the persistence on the plant tissue, the plant species and variety and environmental conditions. In grapevine, a partially purified fraction of Pen was much less toxic than the crude Pen extract, but protected the plants to a similar extent against P. viticola. Our data show that Pen has interesting and unique properties as a plant protection agent, but more research is needed to further reduce its phytotoxic side effects.  相似文献   

A Combination Chemotherapy Protocol (VELCAP-L) for Dogs with Lymphoma   总被引：3，自引：1，他引：2  

Barbara I. Zemann  Antony S. Moore  William M. Rand  Gail Mason  David M. Ruslander  Angela E. Frimberger  Carrie A. Wood  Deborah A. L'Heureux  John Gliatto  Susan M. Cotter 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1998,12(6):465-470

Ninety-eight dogs with lymphoma treated with a 5-drug combination chemotherapy regimen (vincristine, L-asparaginase. cyclophosphamide, doxorubicin, prednisone [VELCAP-L]) were evaluated for pretreatment characteristics predictive for response and remission duration. The complete remission rate was 69%, with a median remission duration of 55 weeks. Dogs with advanced stage of disease, constitutional signs, dogs that were older, and dogs that were dyspneic were less likely to achieve remission. Once in remission, small dogs and dogs without pretreatment thrombocytopenia were likely to have longer remission duration. Toxicoses were frequent, but rarely fatal, and no predictitive factors were found for a dog developing toxicoses. VELCAP-L is an effective treatment for dogs in stage I-III lymphoma, particularly in young, small animals.  相似文献   

Challenging the boundaries     

Barbara Horsfield 《Australian veterinary journal》1997,75(5):372-372

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AVA meets head of new Department     

Barbara Horsfield 《Australian veterinary journal》1998,76(11):765-765

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Setting New Year resolutions     

Barbara Horsfield 《Australian veterinary journal》1997,75(12):914-914

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Organic and inorganic sulfur transport in the xylem sap and the sulfur budget of Picea abies trees     

Köstner B  Schupp R  Schulze ED  Rennenberg H 《Tree physiology》1998,18(1):1-9

Temporal changes in inorganic and organic sulfur compounds (sulfate, glutathione, cysteine, methionine) were analyzed in xylem sap of 40-year-old Norway spruce (Picea abies (L.) Karst.) trees growing on acidic soils at a healthy and a declining stand in the Fichtelgebirge (North Bavaria, Germany). Studies were carried out (1) to quantify glutathione (GSH) transport in the xylem of spruce, (2) to study the significance of reduced sulfur versus sulfate (SO(4) (2-)) transport in the xylem, and (3) to compare total sulfur (S) transport in the xylem with the amount of foliar uptake of SO(2) in an air-polluted environment. Glutathione was the main reduced S compound in the xylem ranging in concentration from 0.5 to 5 &mgr;mol l(-1). Concentrations of inorganic SO(4) (2-) in the xylem sap were up to 50 times higher than those of GSH ranging from 60 to 230 &mgr;mol l(-1). During the growing season, concentrations of all S compounds in the xylem were highest in May (up to 246 &mgr;mol l(-1)) and decreased during summer and fall (up to 21 &mgr;mol l(-1)). On average, SO(4) (2-) concentrations in xylem sap were 30% higher at the declining site compared with the healthy site. Diurnal changes in organic S compounds were significant for GSH and cysteine with high concentrations during the night and low concentrations during the day. Diurnal changes in inorganic concentrations were not significant. Xylem sap concentrations of SO(4) (2-) and cysteine were twice as high and GSH concentrations were tenfold higher in surface roots than in branches. At both sites, transport of organic S was low (up to 3% of total S) compared to transport of SO(4) (2-). Annual transport of total S in the xylem (SO(4) (2-) was the main component) ranged from 60 to 197 mmol tree(-1) year(-1) at the healthy site and from 123 to 239 mmol tree(-1) year(-1) at the declining site. Although gaseous uptake of SO(2) was estimated to be similar at both sites (38 mmol tree(-1) year(-1); Horn et al. 1989), the ratio between annual gaseous uptake of SO(2) and transport of S in the xylem was 1:4 and 1:5 at the healthy and declining sites, respectively.  相似文献   

A Review of Fine Root Dynamics in Populus Plantations   总被引：1，自引：0，他引：1  

R. M. A. Block  K. C. J. Van Rees  J. D. Knight 《Agroforestry Systems》2006,67(1):73-84

Production of native and hybridized varieties of Populus has received considerable interest in temperate regions as an alternative to agricultural crops and an additional wood source, while acting as a potential carbon (C) sink to offset emissions of fossil fuel-based greenhouse gases. Research of root system dynamics in Populus species is expanding, however, our understanding of the nature and role of fine roots (FR) is incomplete. The study objective, therefore, was to review the literature regarding FR production, mortality and longevity in Populus, and evaluate the magnitude and significance of the FR fraction to C sequestration. FRs, conventionally defined as less than 2 mm in diameter and responsible for water and nutrient uptake, are an essential component of the tree. Populus FRs are relatively short-lived, with reported lifespans ranging from 30 to 300 days, depending on root diameter, tree species and age, and soil environmental factors. Standing FR biomass fluctuates throughout the growing season. Fine root production generally peaks in mid-summer, and ranges between 1.0 and 5.0 mg ha⁻¹ yr⁻¹, while FR mortality has less seasonal amplitude. Production and mortality dynamics in Populus are highly plastic in response to soil environmental conditions, and although opposing conclusions have been proposed, research suggests soil moisture and nitrogen to be most important. Results from the literature indicate annual FR turnover to the soil C pool may be small (0.2–1.6 mg C ha⁻¹ yr⁻¹), but substantial in maintaining or enhancing C levels in natural and managed stands of Populus.  相似文献   

Vitalitätsansprache von Fichten auf der Grundlage spektraler Rückstrahlungsmessungen     

Barbara Koch  U. Ammer  H. Wittmeier 《European Journal of Forest Research》1986,105(1):352-357

Zusammenfassung Ziel des Projekts ist die Erarbeitung spektraler Rückstrahlungscharakteristiken von Einzelb?umen und Bestandesoberfl?chen zur Erfassung und kontinuierlichen Beobachtung von Vitalit?tsunterschieden bzw. Sch?digungen an Waldb?umen, insbesondere an Fichten. (Ammer et al. 1983;Hildebrandt 1976). Die für die Spektroradiometermessungen wichtigen objektunabh?ngigen Einflu?parameter wie Sonnenstand, Me?richtung, Neigungswinkel, ?ffnungswinkel und Beleuchtungsverh?ltnisse sind durch eine Vielzahl von Voruntersuchungen bestimmt worden. Erste Me?ergebnisse an Testfl?chen im H?glwald und im Erbersberger Forst lassen deutliche Reaktionen im Spektralverhalten erkennen, die auf Vitalit?ts- und ph?nologische Unterschiede zurückgeführt werden k?nnen.

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Judging vigor of spruces on the basis of spectral reflection measurements

Summary Objective of the research project is the evaluation of characteristic spectral signatures for single trees and stands to assess and continuously monitor differences in vigor, or damages of trees, respectively, especially for spruce. The object-independent parameters which are important for the spectro-radiometer measurements, such as angle and elevation of the sun, inclination, measuring direction, angle of view, and illumination have been determined by numerous previous investigations. First results from the testsites “H?glwald” and “Ebersberger Forst” show distinct differences in the spectral curves which can be related to different degrees of vigor and phenology.

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Beitrag Nr. 16 der H?glwald-Serie 1986  相似文献   

Root architecture might account for contrasting establishment success of <Emphasis Type="Italic">Pseudotsuga menziesii</Emphasis> var. <Emphasis Type="Italic">menziesii</Emphasis> and <Emphasis Type="Italic">Pinus sylvestris</Emphasis> in Central Europe under dry conditions     

Barbara Moser  Christoph Bachofen  Jonathan D. Müller  Marek Metslaid  Thomas Wohlgemuth 《Annals of Forest Science》2016,73(4):959-970

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