bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interaction between Venturia inaequalis and Apple Callus Tissue Cultures: an Electron Microscopic Study
Authors: Beech I. , Gessler C. 
Published: May 2008

AbstractUntrastructural interactions between Venturia inaequalis and callus cultures from scab susceptible and resistant apple varieties, were similar. Host cell wall changes, appositions, and invagination of host plasmamembrane at sites of close contact with fungal hyphae were regularly observed. The ultrastructural observations are described and discussed. The host cell alterations as well as many fungal structures corresponded to those known in young leaves of susceptible apple varieties.
Induced Systemic Resistance in Tomato Plants against Phytophthora infestans
Authors: Heller Werner E. , Gessler Cesare 
Published: May 2008

AbstractInfection of lower leaves of tomato plants with Phytophthora infestans followed by a period unfavourable to disease development increased the general resistance of the plants against the pathogen. Induced resistance to a second infection of upper leaves was expressed in the development of necrotic lesions that were sharply defined and reduced in size. Sporulation of the pathogen was suppressed. Lesions on unprotected plants expanded with a sporulating zone passing gradually to the healthy tissue under the same conditions. Induced resistance delayed and reduced penetration of the pathogen into the epidermis and subsequent colonisation of the mesophyll by formation of papillae in epidermal cells and hypersensitive‐like reactions of penetrated, mesophyll cells.
Ultrastructural and Histochemical Studies on Mildew of Barley (Erysiphe graminis DC. f. sp. hordei Marchal)
Authors: Heitefuss R. , Ebrahim‐Nesbat F. 
Published: May 2008

AbstractPlants of the mildew susceptible barley cultivar Peruvian and the adult plant resistant cultivar Osiris were inoculated with Erysiphe graminis f. sp. hordei at the first and fifth leaf stages. Samples taken at 32 hr after inoculation were examined by electron microscopy to compare papillae associated either with penetration failure or with successful penetration of the fungus into the epidermal cell and haustorium formation. Four types of papillae with ultrastructural differences could, be classified. Although their definite association with fungal ingress or failure is not possible, our data suggest that papillae with larger, more compacted and amorphous or globular structures may be more effective as penetration barriers than others, with more or less uniform distribution of irregular, smaller electrondense structures.
Cross Protection Between Strains of Fusarium oxysporum f. sp. vasinfectum and its Effect on Vascular Resistance Mechanisms
Authors: Hillocks R. J. 
Published: May 2008

AbstractThe severity of symptoms induced in cotton plants by stem inoculation with Fusarium oxysporum f. sp. vasinfectum was reduced by inoculation with a non‐pathogenic strain (NPS) of the fungus 3 days previously. Symptom reduction was associated with reduced populations of the pathogen in the stele tissue of the stem. This cross‐protective response became effective within 24 h of inoculation with the NPS. Although both vascular occlusion and terpenoid aldehyde synthesis were induced by theNPS, the short time required for cross protection to become effective and the duration of the effect, indicated that vascular occlusion rather than fungitoxicity of the terpenoid aldehyde compounds was the mechanism of protection.
Effect of Herbicides and Oat Amendment on Soybean Disease Development and Seed Quality
Authors: Bowman J. E. , Sinclair J. B. 
Published: May 2008

AbstractThe effects of four herbicides and hand weeding and no weeding on soybean disease development and seed quality were studied in the field. Chloramben, dinoseb, fluchloralin, and trifluralin were preplant incorporated at recommended rates. In addition, the effect of an in‐furrow oat (Avena sativa L.) amendment used as an inoculum carrier was studied in all treatments. Compared with the hand‐weeded control, yield, incidence of Septoria leafspot (Septoria glycines), and the recovery of Phomopsis spp. from pod and stem tissues were reduced in the week‐infested control and dinosebtreated plots. Recovery of Alternaria spp. was greater from crown tissues of plants grown in chloramben‐ and fluchloralin‐treated plots compared with, either the weed‐infested or hand‐weeded control. Septoria leafspot ratings and recovery of Phomopsis spp. from various plant tissues were higher in plants from hand‐weeded plots compared with weed‐infested plots, whereas the opposite was truefor, the recovery of Fusarium spp. Chloramben‐treated plots were high‐yielding and had the best weed control of all herbicide treatments. Seed quality was not affected by herbicide treatment. Plants from furrows with autoclaved oats had a lower incidence of Septoria glycines, a greater recovery of Fusarium spp. from pod and stem pieces, and produced seed with lower quality than plants from rows with no oat amendment.
The Nature of Systemic Invasion of Stem and Leaves of Sunflowers by Plasmopara helianthi Novot. var. helianthi Novot. with Mechanism of Sporulation and Zoospore Release
Authors: Döken M. Timur 
Published: May 2008

AbstractDuring the systemic development of Plasmopara helianthi Novot. var. helianthi Novot. the hyphae in the stem advance especially through the intercellular spaces of loose parenchyma forming haustoria in adjacent cells. The hyphae which reach leaf blades through petioles continue their growth along the main veins intercellularly in non‐vascular tissues enclosing the vascular bundles. At the same time, the hyphae spread to intercellular spaces of spongy parenchyma where the growth is limited by the veinlets resulting in angular chlorotic lesions.Under humid conditions the sporangiophores arising from the aggregated hyphae in a substomatal cavity emerge through the stomatal pore on the lower side of the leaf and zoosporangia are borne terminally on sporangiophores. Soon after biflagellated zoospores are liberated into distilled water from the zoosporangia, they retract their flagellae and then lyse.
Phialophora parasitica, Causal Agent of Cherry Dieback
Authors: Rumbos I. C. 
Published: May 2008

AbstractA serious fungal disease causing dieback symptoms on cherry tree was observed in the period 1982–86 in different locations of Greece. Isolations from affected branches yielded consistently the fungus Phialophora parasitica. Pathogenicity tests carried out on cherry, apricot, olive and peach trees showed that the pathogen was capable to induce disease symptoms on all these fruit trees.
Variability in Sensitivity to Polyoxin B of Isolates of Alternaria mali and Decreased Fitness of Polyoxin resistant Isolates
Authors: Hwang Byung Kook , Yun Ju Ho 
Published: May 2008

AbstractThe 540 monoconidial isolates of Altemaria mali were obtained in 1983 from apple orchards at Seoul, Suweon, Cheongju, Kochang, Daegu, and Jinju in Korea. The sensitivity of A. mali to polyoxin B greatly varied among isolates and locations. Most of isolates were sensitive to polyoxin B, but 11 isolates showed a high level of resistance, particularly from Kochang and Daegu where polyoxin B had been applied frequently. Conidial germination and mycelial growth of resistant isolates were not inhibited at higher concentrations of polyoxin B compared to the sensitive ones. The polyoxin‐resistant isolates were not resistant to the fungicides iprodione and polydong and showed a reduced activity for conidial formation and mycelial growth. The isolates of A. mali with resistance to polyoxin B appear to have decreased fitness in nature.
The Effect of Glumes on Fungal Infection of Germinating Seed of Spelt (Triticum spelta L.) in Comparison to Wheat (Triticum aestivum L.)
Authors: Riesen Th. , Winzeler H. , Rüegger A. , Fried P. M. 
Published: May 2008

AbstractThe influence of fungi on seedling emergence of naked and hulled spelt (Triticum spelta L.) and winter wheat (Triticum aestivum L.) was investigated. Seeds were sown in flat trays and placed in a growth chamber under stress conditions (low temperature and water logging) for four weeks, followed by favourable growth conditions. At weekly intervals, 150 seeds were removed, surface sterilized, and investigated for fungi. Pythium aristosporum Vanterpool, a causal agent of damping‐off, was found to be best adapted to the unfavourable conditions and to be a major cause of pre‐emergence damping‐off. The frequency of seed‐borne fungi decreased during the stress period, whereas soil‐borne fungi survived and could be isolated from seeds and glumes in the following period with more favourable growth conditions. Seedlings from hulled seeds of spelt emerged more frequently than from naked kernels of spelt and both emerged at a higher rate than from seeds of winter wheat. This is good evidence that glumes protect seeds against fungal colonization and therefore increase the fitness of spelt under unfavourable germinating conditions.
Pathogenic Potential of Soil Fusaria from Malaysian Oil Palm Habitats
Authors: Ho Y. W. , Varghese G. 
Published: May 2008

AbstractA total of 353 Fusarium isolates consisting of 8 species and 2 varieties obtained from the soils of 22 sampling sites in oil palm habitats in Peninsular Malaysia was tested on 2‐leaf stage oil palm seedlings. None of the isolates tested produced any symptoms of vascular wilt or other diseases. However, some of the isolates did have an adverse effect on the growth and vigour of the palms. They were found to cause significant reduction in palm growth. Isolates causing a reduction in the growth of the oil palm seedlings were not confined to a certain type of soil or a particular location.
Isolation and Characterization of a Virus Inhibitor from Spinach (Spinacia oleracea L.)
Authors: Straub Petra , Adam G. , Mundry K.‐W. 
Published: May 2008

AbstractA virus inhibiting protein (VI) was isolated from spinach (Spinacia oleracea L.). The VI inhibited infections of test plants with plus‐ and minus‐strand RNA viruses. Inoculation of both local lesion and systemic hosts with TMV in the presence of varying amounts of the VI resulted in typical dose response curves for the number of local lesions or the amount of virus respectively. The lowest concentration of VI leading to a significant reduction in the number of local lesions was 0.06 μg/ml. The VI was found to inhibit local lesion formation only when applied within 2–3 h p.i. but still reduced the number of local lesions when applied up to 9 h prior to virus inoculation.The antiviral activity could be attributed to a protein of molecular weight 29,000 dalton with an isoelectric point of 10.3. Its activity was destroyed by heating for 30 min to 70°C. These characteristics resemble those of other virus inhibiting proteins described for members of the order Caryophyllales such as the Phytolacca inhibitor against which a serological relationship was obtained.
Factors Affecting the Production of Antifungal Compounds by Enterobacter aerogenes and Bacillus subtilis, Antagonists of Phytophthora cactorum1
Authors: Gupta V. K. , Utkhede R. S. 
Published: May 2008

AbstractThe effects of temperature and pH on the production of antifungal compounds and growth in sterilized soil of Enterobacter aerogenes and Bacillus subtilis, antagonists of Phytophthora cactorum, the cause of crown rot of apple trees, were studied. With E. aerogenes maximum amounts of antifungal compounds were produced between 14 and 21°C and at pH levels between 3.5 and 5.0. Bacillus subtilis produced maximum amounts of antifungal compounds between 21 and 28°C andwith pH levels between 5.0 and 8.0. P. cactorum inoculum, produced in the presence of E. aerogenes or B. subtilis at optimum temperature and pH levels, was significantly less virulent compared with controls. The optimum temperature of maximum population growth in sterilized soil for E. aerogenes was 18°C and for B. subtilis 25°C. The population growth of B. subtilis was much slower than that of E. aerogenes. Fosetyl Al stimulated the multiplication of bacteria at lower temperatures while metalaxyl had the same effect at higher temperatures. These results indicate that populations of these antagonistic bacteria increase in sterile soil up to the 33rd day from inoculation and that the fungicides fosetyl, Al and metalaxyl did not limit their multiplication and production of antifungal compounds.
Hyperparasitism of Streptomyces albus on a Destructive Mycoparasite Nectria inventa
Authors: Tu J. C. 
Published: May 2008

AbstractUsing scanning electron microscopy, Streptomyces albus was proved to be a hyperparasite of Nectria inventa, itself a well‐known mycoparasite on many fungi. The hyperparasite had no apparent antagonistic activity against N. inventa, but did have intense tropic response toward it. Upon contact with the host, the hyperparasite grew along, and formed appressorium‐like structures on the host hyphae. The parasitism that led to the eventual collapse of the host cells was not necessarily accompanied by actual hyphal penetration. The hyperparasite could, however, readily penetrate the host hyphae, and its hyphae were frequently found inside the host hyphae.
Zum Einfluß von Pythium ultimum und Cochliobolus sativus auf Wachstum und Wurzelleistung der Wintergerste in Abhängigkeit vom Düngungsniveau
Authors: Brinkmann R. , Schönbeck F. 
Published: May 2008

Abstract Influence of Pythium ultimum and Cochliobolus sativus on growth and root efficiency of winter barley dependent on fertilizer level The colonization of barley roots by Pythium ultimum and Cochliobolus sativus can be symptomless or cause root rot. Disease severity of the root systems was increased at higher fertilizer level. Since root length growth was much more affected than shoot growth, the undamaged roots of an infected root systems had an increased efficiency per unit root length. Nevertheless the total root systems, when infected, were positively inferior to the healthy ones. Their utilization of additionaln, utrients was less efficient. This indicates the importance of root health in economical and ecological respect.
Ultrastructural and Histochemical Studies on Mildew of Barley (Erysiphe graminis DC. f. sp. hordei Marchal)
Authors: Ebrahim‐Nesbat F. , Heitefuss R. , Rohringer R. 
Published: May 2008

AbstractFifth leaves of the barley cultivar ‘Osiris’ with adult plant resistance against powdery mildew were inoculated with Erysiphe graminis f. sp. hordei. Samples were taken at 32 hours after inoculation for cytochemical treatments and electron microscopy. Deposition of gold‐labelled wheat germ lectin was detected in the wall of the haustorial neck of the fungus and in an outer layer of a papilla, indicating the presence of oligomers of N‐acetylglucosamine. Con A binding was detected mainly, in a middle layer of a papilla, demonstrating the presence of α‐bound glucose and/or mannose. Treatment with PA‐TSH‐SP revealed glycosubstances with vicinal hydroxyl groups present mainly in an outer layer of another type of papilla. Pretreatment with, protease before PA‐TSH‐SP staining resulted in a positive Thiery reaction in spherical structures of a papilla, indicating that vicinal hydroxyl groups were exposed to staining after removal of protein from these structures.
Nutzung von In‐vitro‐Pflanzen der Kartoffel zur Prüfung der antiphytoviralen Wirkung von 2,4‐Dioxohexahydro‐1,3,5‐triazin (DHT) in Kombination mit N‐Cyanoguanidin
Authors: Bittner H. , Schenk G. , Schuster G. 
Published: May 2008

Abstract Suitability of in vitro potato plantlets for testing of antiphytoviral effect of a combination of 2,4‐dioxo‐hexahydro‐1,3,5‐triazine (DHT) and N‐cyano guanidine The suitability of a semiquantitative determination of virus content for the detection of antiphytoviral effects of chemicals was demonstrated by ELISA directly applying at in vitro potato cultures systemically infected and chemotherapeutically treated. The combination of 2, 4‐dioxohexahydro‐1,3,5‐triazine (DHT) and N‐cyanoguanidine both applied at a concentration of 0.03% to the culture medium resulted in a high significant reduction of the relative concentration of the potato virus S in the, potato genotype ‘M‐812820’ of 44–73 %. A phytotoxic influence of the substances was not observed. The combination of the two antiphytoviral substances had no effect against potato virus Y in explants of the variety ‘Ackersegen’. Differences in the susc, eptibility of various genotypes against biologically active substances were indicated.
Identification of Scopoletin as a Phytoalexin of the Rubber Tree Hevea brasiliensis1
Authors: Giesemann A. , Biehl B. , Lieberei R. 
Published: May 2008

AbstractIn leaves of Hevea sp. the production of a blue fluorescing phytoalexin is induced by various fungi. This compound is shown by chromatographic and spectrophotometric means to be scopoletin.
Factors Affecting Race Prevalence of Melampsora lini1
Authors: Saharan G. S. , Singh B. M. 
Published: May 2008

AbstractNo correlation was found between virulence of races and their prevalence, although races which attacked one or two genes for resistence only constituted more than 71% of the isolates studied. Differences in race prevalence were not associated with their incubation or latent period. Uredospore germination of races differing in virulence indicated that a race of narrow virulence and wide prevalence germinated better over a wider range of temperature than races of higher virulence and showed better germ tube elongation at extreme temperatures. These factors may be in part responsible for the wider prevalence of some races.
Stalk Rot of Maize: Host‐pathogen Interaction
Authors: Chambers K. R. 
Published: May 2008

AbstractFour maize cultivars were each separately inoculated with 10 different isolates of Diplodia zeae, Fusarium moniliforme, F. graminearum and Macrophomina phaseolina. D. zeae consistently caused most stalk rot, followed in decreasing order by M. phaseolina, F. graminearum and F. moniliforme. Significant intraspecific differences in stalk rot were recorded. No significant stalk rot x cultivar interaction occurred. Stalk rot correlated non‐significantly with yield loss but significantly with cellulase production in vitro.
Fusarium lateritium Nees ex Link as a Parasite and Host in Interfungal Hyphal Interactions
Authors: Vajna L. 
Published: May 2008

AbstractIn dual cultures Fusarium lateritium Nees ex Link coiled, penetrated and destroyed young actively growing hyphae of Botrytis cinerea Pers., Cytospora rubescens Fr., Eutypa armeniacae Hansf. et Carter, Sphaeropsis malorum Peck, Rhizoctonia solani Kühn, Trichoderma koningii Oud. (Tk‐1) and Trichoderma hamatum (Bon.) Bain. (Tha‐2), and conidiophores and conidia of Botrytis cinerea Pers. The isolates of Trichoderma koningii Oud. (Tk‐3) and Trichoderma pseudokoningii Rifai (Tp‐1) parasited and destroyed the hyphae of Fusarium lateritium. There was no hyphal interaction between Fusarium lateritium and an isolate of Trichoderma longibrachiatum Rifai. Hyphal, interactions occurred mostly on the aerial hyphae of test fungi which grew over the inhibition zone formed between the colonies of Fusarium lateritium and the test fungus, and contacted the hyphae of Fusarium lateritium.Details of dual culture studies are given.
Induced Resistance in Hypersensitive Tobacco Against Tobacco Mosaic Virus by Injection of Intercellular Fluid from Tobacco Plants with Systemic Acquired Resistance
Authors: Wieringa‐Brants D. H. , Dekker W. C. 
Published: May 2008

AbstractAcquired resistance in hypersensitive tobacco plants against tobacco mosaic virus (TMV) was induced by components occurring in the intercellular fluid (IV) obtained from virus‐infected plants or by plant cell wall components. Induced resistance could be transmitted through seed to the progeny. Lesion size and number were reduced significantly when the progeny was tested by TMV‐inoculation.IV was extracted from the upper uninoculated leaves of four times TMV‐inoculated Nicotiana tabacum cv. ‘Xanthi’ nc plants. Injection of IV from induction‐inoculated plants (SAR‐IV) into leaves of healthy plants followed by TMV‐infection reduced lesion size significantly. A concentration of 5 × 10−7 g SAR‐IV/ml was still active. IV from healthy plants was inactive. The IV's were partly purified by gel filtration on a Sephadex G‐50 column. Some fractions were active in inducing resistance as expressed in reduction of lesion size. Fractions of control‐IV were inactive.It is still unknown whether the active substances in SAR‐IV are in fact cell wall fragments acting as regulatory molecules in disease resistance.
The Role of Calcium Nutrition on Fusarium‐Wilt Syndrome in Muskmelon
Authors: Spiegel Y. , Netzer D. , Kafkafi U. 
Published: May 2008

AbstractThe influence of various calcium salts was evaluated on non‐inoculated muskmelon plants and on plants inoculated with the Fusarium‐wilt pathogen, and maintained in silica sand or vermiculite. Disease severity of inoculated seedlings maintained in vermiculite was markedly higher than that of seedlings grown in silica sand, and onset of wilt was recorded earlier in the former. These trends were more conspicuous in seedlings treated with Ca2+, especially when this cation was accompanied, by nitrate. In vermiculite–compared with silica sand, Mg and K contents in the shoot were higher while Ca values were lower. Irrespective of the form of calcium salt or the plant's growth medium, the Ca concentration was higher in Fusarium‐inoculated shoots while K content was depleted, compared with non‐inoculated plants.
Deposition of Erysiphe graminis Conidia on a Barley Crop
Authors: McCartney H. A. , Bainbridge A. 
Published: May 2008

AbstractNaturally released Erysiphe graminis conidia were trapped (on horizontal slides, on vertical sticky cylinders and in suction traps) in a barley crop infected with powdery mildew and the numbers of single spores and of clumps of different sizes deposited on the traps were counted. The efficiencies of impaction calculated from deposits and wind speed measurements were higher than expected from mean wind speed measurements. The values were consistent with the hypothesis that spores were removedpredominantly in gusts. More than half the conidia were removed in clumps of two or more spores. The measurements suggest that clumps were more effectively deposited than single spores. The measurements demonstrate that spore release mechanisms can influence spore deposition significantly, especially close to the source.