bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temperature‐induced Alterations in the Expression of Susceptibility of Cassava to Colletotrichum gloeosporioides f. sp. manihotis
Authors: Bruggen P. van der , Gregoire D. , Maraite H. 
Published: May 2008

AbstractCassava plants (Manihot esculenta Crantz) were incubated at 15, 25 or 35 °C after inoculation of green stems with Colletotrichum gloeosporioides (Penz.) f. sp. manihotis Chev. At 25 °C, the cultivar TMS 30211 was less susceptible than the cultivar TMS 30337. At 35 °C, compared to 25 °C, the lesion diameter was reduced in both cultivars, the cassava stem extracts showed an enhanced fungitoxicity, the grem tubes were more sensitive to the stem extracts and a layer of lignified, cells developed earlier around the infected tissues. At 15 °C, the lesions in both cultivars extended more rapidly than at the other temperatures, even though 15 °C, compared to 25 °C, caused a 50% reduction of mycelial growth rate on oat meal agar.
Effects of Different Cropping Systems on the Occurrence of Fluorescent Pseudomonads
Authors: Mohamed Elsherif Dr. , Grossmann F. 
Published: May 2008

AbstractIn field experiments, winter wheat was grown under different crop rotation regimes (monoculture; rotation with field beans) and differentiated intensity (cv.‘Jubilar’ with 120 kg N/ha and 1l CCC/ha; cv.‘Okapi’ with 180 kg N/ha and l CCC/ha). Plant, protection measures were carried out at three levels (no treatment; specific treatments under consideration of damage thresholds; routine spraying program). The occurrence of aerobic bacteria, fluorescent pseudomonads and strong siderophore‐producers as well as the effect of the different cropping systems on the two groups of bacteria mentioned last were determined during the vegetation period at the beginning of shooting, at full bloom and after harvesting on the surface of the roots of wheat plants. In comparison to the total population of aerobic bacteria, the populations of fluorescent pseudomonads and of the strong siderophore‐producing bacteria changed in a characteristic way: whereas at the beginning of shooting the highest and at full bloom the, lowest numbers were determined, a slight increase could be observed after harvest.On roots of wheat plants in monoculture, higher numbers of fluorescent pseudomonads and strong siderophore‐producers were detected at the begining of shooting and at full bloom, than on those grown in rotation with field beans. The roots of cv. ‘Okapi’ (higher cropping intensity) were colonized to a higher degree by both groups of bacteria as compared to those of cv. ‘Jubilar’. After application of herbicides, a stimulation of these micro‐organisms was observed at the beginning of shooting.The influences of different crop rotation schemes, intensities of cropping and plant protection measures on the occurrence of fluorescent pseudomonads were altogether less pronounced than the natural fluctuations of the population during the growth of the wheat.On the basis of morphological, physiological and biochemical properties, it could be shown that different biovars of the species Pseudomonas fluorescens dominated in the experimental field.
Effect of Nitrogen and Powdery Mildew on the Yield Formation of Two Winter Barley Cultivars1
Authors: Oerke E.‐C. , Schönbeck F. 
Published: May 2008

AbstractIn field experiments the effect of powdery mildew on the yield formation of two barley cultivars ‘Catinka’ (partially resistant) and ‘Tapir’ (susceptible) was investigated in relation to three levels of nitrogen fertilization (40, 90, 150 kg N/ha). Nitrogen increased especially the single ear yield of cv.‘Catinka’, whereas cv.‘Tapir’ showed symptoms of N oversupply. Infection density of Erysiphe graminis hordei also increased with increased nitrogen supply, although it decreased transiently, at the highest N level for cv.‘Tapir’. In general, cv.‘Catinka’ was less tolerant to infections with E. graminis than cv.‘Tapir’, but yield response of both cultivars to powdery mildew (17, 11 and 8 % and 12, 16, and 12 % yield losses for cv.,‘Catinka’ and ‘Tapir’. respectively) showed cultivar × nitrogen interrelationships. Starch and protein contents of grains indicated differences in the intensity of detrimental effects caused by powdery mildew limiting the formation of carbohydrates and/or the translocation processes. Regression analysis demonstrated a closer correlation of yield losses with the photosynthetically active leaf area (r =+0.96 and +0.93 for ‘Catinka’ and ‘Tapir’) than with disease intensity (r =−0.32 and −0.85). Theinte,rpretation of disease/yield loss relations and the detrimental effect of powdery mildew are discussed with reference to plant resistance, remaining green leaf area, the availability of nutrients, to ‘sink and source’ conditions and to the occurrence of,additional environmental stresses.
Pathogenicity of Some European Collections of Crown Rust (Puccinia coronata Corda) on Cultivars of Perennial Ryegrass
Authors: Potter L. R. , Cagaś B. , Paul V. H. , Birckenstaedt E. 
Published: May 2008

AbstractThree collections of crown rust (Puccinia coronata), from Czechoslovakia, West Germany and the U.K., were tested for their pathogenicity on sixteen cultivars of perennial ryegrass. The Czechoslovakian collection had the highest level of infection on twelve of the cultivars, although with most cultivars there were no significant differences in infection levels. Three cultivars, although with most cultivars there were no significant differences in infection levels. Three cultivars, Kerem, Loret, ta and Tando, contained qualitative resistance to crown rust which was overcome by the Czechoslovakian collection, although they retained a moderately high level of background resistance to this collection.
Differentiation of Closely Related Globodera pallida (Stone) Populations by Means of DNA Restriction Fragment Length Polymorphisms (RFLPs)
Authors: Schnick D. , Rumpenhorst H. J. , Burgermeister W. 
Published: May 2008

AbstractA small genomic library from DNA of G. pallida population Delmsen (pathotype 3) was constructed. A number of clones were tested as hybridization probes with 21 G. pallida and 6 G. rostochiensis populations. The two species were easily distinguished by their hybridization patterns. A total of 32 RFLP markers were identified which permitted the differentiation of all G. pallida populations. By means of cluster analysis of the RFLP data the genetic distances between the 21,G. pallida populations were calculated and a dendrogram was constructed. The arrangement of the 21 G. pallida populations in the dendrogram suggests a partial correlation between genetic distance and virulence according to biological pathotyping.
Biological Control of Macrophomina phaseolina Charcoal Rot of Sunflower and Mung Bean
Authors: Hussain S. , Ghaffar A. , Aslam M. 
Published: May 2008

AbstractInfection by Macrophonina phaseolina was substantially reduced following treatment of sunflower and mungbean seeds with Trichoderma harzianum, Gliocladium virens, Paecilomyces lilacinus or Streptomyces sp. which gave promising control of charcoal rot disease. Treatment of mungbean seeds with Rhizobium meliloti also gave good disease control.
Alternaria cassiae Alters Phenylpropanoid Metabolism in Sicklepod (Cassia obtusifolia)
Authors: Hoagland R. E. 
Published: May 2008

AbstractPhenylpropaniod metabolism has been implicated in plant defence mechanism(s) against pathogen attack. In this study, phenylpropanoid metabolism was examined over a 72 h time course in the weed sicklepod (Cassia obtusifolia) in relation to pathogenic effects of the fungus Alternaria cassiae. When 3‐ to 4‐week old seedlings were challenged by the pathogen, extrable phenylalanine ammonia‐lyase (PAL, E.C. 4.3.1.5) activity was dramatically increased above that in uninfected plants severalhours after inoculation and exposure to dew. Greatest increases of enzyme activity (3‐fold, specific activity basis) occurred at ca 15–23 after treatment with fungal spores. After this peak of activity, PAL activity declined with time in infectedtissue, but remained greater than in uninfected plants through 65 h after treatment. Total methanol‐soluble hydroxyphenolic compound levels (PAL products) were higher in shoots (stems and leaves) of infected plants at 48–72 h. Leaves contained a higherconcentration (per gram fresh weight) of hydroxyphenolic compounds than did stems, and infected leaves exhibited a phenolic content greater than that of uninfected leaves at ca 27–72 h. Increased soluble phenolic compound production correlated with the appearance of lesions and necrotic spots on leaves and stems. UV irradiation examination and spectrofluorometric analysis of thin layer chromatographic separations of methanolic exatracts revealed a substantial increase of several components ininfected tissue 48 h after inoculation. Results support the view that PAL activity increases correlate with increased phenolic compound production in this host/pathogen interaction.
Induction of β‐1,3‐Glucanase and Chitinase Activity in Compatible and Incompatible Interactions Between Colletotrichum lindemuthianum and Bean Cultivars
Authors: Daugrois J. H. , Lafitte C. , Barthe J. P. , Touze A. 
Published: May 2008

AbstractInoculation of different bean cultivars with Colletotrichum lindemuthianum race β results in a marked increase of β‐1,3‐glucanase and chitinase activities. The increase is much faster in incompatible than in compatible interactions. Induced β‐1,3‐glucanase (pI 9,5) differs from the constitutive β‐1,3‐glucanase (pI 4,5) of healthy plants. The induced enzyme can partly degrade, in vitro, the cell walls of C. lindemutianum. The possible role of these hydrolytic enzymes inplants defence is discussed.
The Effects of Temperature on the Respiratory Responses of Groundsel (Senecio vulgaris) to Infection by Rust (Puccinia lagenophorae)
Authors: Jennings Diane , Ayres PeterG. 
Published: May 2008

AbstractGroundsel (Senecio vulgaris) was grown in either a warm (20°C) or a cool (8°C) controlled environment and infected with Puccinia lagenophorae. Dark respiration, measured over the range 6 to 18°C, was higher in leaves of healthy plants grown under low temperatures than in those of plants grown under high temperatures. Infection increased the rates of dark respiration in the region of sporulating lesions in both sets of plants, but the greater increase in plants grown under warm conditions resulted in both sets having similar respiration rates across the range 6 to 18°C. The conclusion that the magnitude of the respiratory increase following rust infection depends upon the conditions under which plants were grown is supported by literature on other rust diseases and has implications for the utilization of carbohydrate reserves and the survival of both rust and host populations over winter.
Physiologische Eigenschaften des PilzesTrichoderma longibrachiatumRifai und seine Pathogenität für Maiskeimlinge bzw. junge Maispflanzen1
Authors: Maček J. , Celar F. 
Published: May 2008

AbstractPhysiological properties of the fungusTrichoderma longibrachiatumRifai and its pathogenicity for maize seedling and young maize plantsIn the 1977–1980 periodTrichoderma longibrachiatumwas found to make 1.7 % of the maize seed mycoflora in Slovenia/Yugoslavia. Its mycelium growth was investigated on complex as well as on defined substrates with regard to spore formation, light induction (which is indispensable for spore formation), temperature requirements, relative humidity and different C‐ and N‐sources. These observations showed that the properties of the investigated fungus are those which characterize otherTrichodermaspecies as well.
Mechanisms Involved in Biological Control of Dutch Elm Disease
Authors: Scheffer R. J. 
Published: May 2008

AbstractAn effective suppression of Dutch elm disease symptom development was observed in elms resistant to the non‐aggressive strain of Ophiostoma ulmi, but not to the aggressive strain, after a preventive treatment by this non‐aggressive strain. Anequally effective isolate of Verticillium dabliae suppressed symptom development even in the very susceptible field elm (Ulmus carpinifolia).Induction of resistance is proposed for the major mechanism explaining these and earlier experiments. The primary stimuli initiating a resistance reaction are unknown, but the intermediates of the univalent reduction of oxygen may play a role. In an experiment the activities of two groups of enzymes involved in the catalytical scavenging of these radicals, superoxide dismutase and peroxidase, were monitored, but no correlation with induction of resistance was observed. Resistant elms showed the highest activities, probably reflecting a more effective defence against radicals than susceptible ones.
Erwinia amylovra Infection of Hawthorn Blossom: III. The Nectary
Authors: Wilson M. , Sigee D. C. , Epton H. A. S. 
Published: May 2008

Abstract The nectaries of hawthorn flowers on detached branches were inoculated with Erwinia amylovora and the population development was followed by viable counts and light and electron microscopy. On nectaries bearing surface moisture at the time of inoculation (“wet nectary” material), the population increased rapidly after a short drop, or lag, lasting 6–12 h. Scanning electron microscopy showed that bacteria had multiplied within the nectarthodes during the first 6 h after inoculation, although, the total population had dropped. Death of cells on the surface of the nectary, possibly due to desiccation, may account for the overall drop. This differential response is not consistent with a bactericidal effect of the hawthorn nectary. On nectaries lacking surface moisture at the time of inoculation (“dry nectary” material), there was a 36 h lag period before the population started to increase – which coincided with the commencement of nectar production.Although the nectary is an important site of infection during humid periods, the role of contaminated nectar in blossom‐to‐blossom spread of the disease is probably not of great importance.
Production of Phytohormones by Pseudomonas amygdali and their Role in the Hyperplastic Bacterial Canker of Almond
Authors: Iacobellis N. S. , Evidente A. , Surico G. , Sisto A. , Gammaldi G. 
Published: May 2008

Abstract The cytokinin and auxin production by Pseudomonas amygdali was studied in relation to bacterial virulence on almond plants. All isolates of Pseudomonas amygdali used in this study secreted indoles and cytokinins in culture medium although their relative amount varied among the strains. t‐zeatin (t‐Z) and indole‐3‐acetic acid (IAA), which proved to be the main componenets of cytokinin and indole mixtures, ranged respectively, as determined by HPLC, from 0.013 to 4.621 mgl,−1 and from 0.1 to 15.14 mg l−1.The production of IAA and t‐Z appeared to be correlated to virulence of P. amygdali. The highly virulent strains, having the shortest incubation period and inducing the longest cankers produced high levels of IAA and t‐Z in vitro. On the other hand, the weakly virulent strains, having longer incubation periods and inducing shorter cankers, secreted low levels of IAA and t‐Z. Strain A142, producing high level of IAA and low level of t‐Z had the same incubation, period as the highly virulent strains but a canker similar to that of the other weakly virulent strains.These results suggest that in the disease process by P. amygdali on almond the amount of IAA and cytokinins are correlated respectively to the length of the incubation period and to the final length of the cankers.
Sclerotinia sclerotiorum: Epidemiological Factors Affecting Infection of Greenhouse Aubergine Crops
Authors: Torés J.A. , Moreno R. 
Published: May 2008

AbstractA series of greenhouse cultivations of Aubergine plants were studied for a three‐year period which included the 1981—1982, 1984—1985 and 1985—1986 growing seasons to determine the number of infections produced by S. sclerotiorum and the plant organs infected. A time‐phase difference was detected between the discharge of air‐borne spores and the appearance of infections. The appearance of flowers, the plant organ most susceptible to infection, appeared to mark the end of the latent period and the beginning of infections. The distribution of the infections within the greenhouse was random for two of the three seasons studied and fitted a Poisson distribution (p < 0.01). Analysis of the tendencies of the number of infections and numbers of infected plants revealed a sigmoidal curve that was a function of the accumulated hours in which relative humidity was 80 % or more.
Populationsänderungen von Pseudocercosporella herpotrichoides mit und ohne Fungizidselektion
Authors: Waldner‐Zulauf M. , Gisi U. 
Published: May 2008

Abstract Population changes in Pseudocercosporella herpotrichoides with and without fungicide selection A conidium mixture of W (wheat‐type) and R (rye‐type) strains of Pseudocercosporella herpotrichoides (W:R = 1:1) was incubated on PD‐agar without fungicide or amended with the imidazole prochloraz or the triazole cyproconazole. The W:R ratio was assessed over four generations using the different benomyl sensitivity of the strains as marker. In untreated mixtures, the R strain completely dominated the population already after two generations. Similarly, in cyproconazole‐treated mixtures, the R strain increased to 100% after the second generation, whereas in prochloraz‐treated mixtures the R strain either followed the same pattern as in untreated mixtures or fluctuated around the initial proportion of 50% over four generations. The W and R strains displayed different fitness properties. The average hyphal growth rate was 8.5 mm/10 d and 4.5 mm/10 d for the W and the R strains, respectively; the sporulation capacity was 80 and 400 conidia/colony, respectively, for the two strains. The different fitness resulted in a strong dominance of the R strains both in vitro and in field populations towards the end of the vegetation period. This shift towards R‐dominance occurred about equally fast with or without fungicide selection.
Infection of Arabidopsis thaliana by Plasmodiophora brassicae
Authors: Koch E. , Cox R. , Williams P. H. 
Published: May 2008

AbstractThree populations of Arabidopsis thaliana (L.) Heynh. were inoculated with three isolates of Plasmodiophora brassicae Woron. Inoculation of young Arabidopsis plants caused clubbing of roots and, in the late flowering population CrGC 9–4, infection of shoots. In this population, the number of inoculated plants reaching the flowering stage was reduced, and the majority of plants died prematurely. Symptoms of shoot infections were compressed rosettes with thickened and stunted leaves containing resting spores of P. brassicae. The results showed clearly that A. thaliana is susceptible to P. brassicae.
Mechanism of Cold‐induced Peach Stem Infection by Pseudomonas s. pv. persicae: Water Congestion in Tissues
Authors: Vigouroux A. 
Published: May 2008

AbstractWe have previously shown that water congestion in tissues, caused by thawing after a period of slightly negative temperatures, results in the absorption and diffusion of bacteria in the bark tissues of peach stems (Prunus persica). In the present study we demonstrate that in peach branches acclimated to cold and inoculated with the bacterium Pseudomonas syringae pv. persicae, this freezing‐thawing process is sufficient to induce, with no further treatment than incubation at + 10 °C, the development of cankers very similar to those observed in orchards in the winter. The first step of the process induces a particularly effective form of contamination and thus corresponds to an epidemiological phenomenon. The diffused bacterium, then, initiates pathogenic activity in locations favorable to its development. Moreover, an additional freezing‐thawing sequence can result in the extension of ongoing infection by causing diffusion of bacteria from infected tissue to healthy areas.
Ascospore Discharge and Survival in Pseudopezicula tracheiphila, Causal Agent of Rotbrenner of Grape
Authors: Pearson R. C. , Siegfried W. , Bodmer M. , Schüepp H. 
Published: May 2008

AbstractA recording volumetric spore trap was operated continuously amidst overwintered grape leaves in a vineyard at Walenstadt, Switzerland from early May to mid‐July 1988. Ascospores of Pseudopezicula tracheiphila were captured in the air beginning 11 May and 96 % of the total seasonal release occurred between 16 May and 2 June. Rain always preceded ascospore release. However, trap catches were associated with the simulataneous cessation of rainfall, decreased relative humidity (RH), increased temperature, and drying of foliage. Maximum ascospore release occurred in the second hour, following commencement of drying. Ascospores discharged dry onto glass coverslips survived with greater than 60 % viability after 1, 3, and 6 days exposure to 10, 15, 20, and 25°C at 70 % RH. Only at 30°C was viability reduced to slightly less than 50 % after 6 days.
Virus Free Garlic (Allium Sativum L.) Plants Obtained by Thermotherapy and Meristem Tip Culture
Authors: Conci VilmaC. , Nome S. F. 
Published: May 2008

AbstractVirus infection in garlic considerably reduces yield and quality in Argentina. The production of virus free “seed” was attempted by means of thermotherapy and meristem tip culture.A hot water treatment was employed to determine the lethal temperature/time combination for clonal type (c.t.) Blanco cloves. It was established that 50°C × 20 min, 50°C × 15 min and 55°C × 5 min were the limit thermal/time combinations which garlic could withstand. Those treatments were employed followed by meristem tip culture, however, none of the successfully developed plants after culture (only 13 %) were virus‐free.Hot air treatments in a growth chamber at 36°C lasting for 30, 40 and 60 days, and at 25°–32° for 30 days in a greenhouse were tested on c.t. Blanco. Cloves kept at room temperature throughout the experiment were employed as controls. In the 25°–32°C treatment, 73% of meristems produced plants and, of these, 33 % were virus free. After 30 and 40 days at 36 °C, 62 % and 67 % of the meristems developed into plantlets, of which respectively 51 % and 50 % were virus‐free. Very few meristems (10 %) developed into plants when cloves had been kept at 36°C for 60 days but the resulting plantlets were all virus free. Controls produced 78 % of plants, of which 14 % were virus free.Results of hot air treatments of 36 °C for 40 days performed on c.t. Colorado, Rosado, Paraguayo, Espaol and Hilario Ascasubi were similar to those obtained with c.t. Blanco. In Espaol and Hilario Ascasubi, no virus‐free plants were detected among control specimens (no thermotherapy treatment).The only virus (from up to 3 that infected the plants) that persisted in some plants after themotherapy and meristem tip culture was garlic yellow streak.