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  • onion fly  (4)
  • Electron microscopy  (3)
  • Triticum aestivum  (3)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 43 (1987), S. 279-286 
    ISSN: 1570-7458
    Schlagwort(e): Delia antiqua ; Hylemya ; Anthomyiidae ; onion fly ; antixenosis ; oviposition behaviour ; plant-insect interactions ; resistance ; host-plant stimuli
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé A la lumière d'opinions récentes concernant la découverte des plantes-hôtes par D. antiqua, nous avons examiné les conditions de la ‘résistance’ chez plusieurs lignées de A. cepa les moins attaquées lors d'essais en plein champ aux Pays-Bas, et dont on considérait que la ‘résistance’ était due à une antixénose. Des femelles gravides en présence, au laboratoire, d'un choix de plants de 6 semaines, pondent en moyenne 1,6 à 34,8 oeufs par plant. Les différences entre les pontes correspondent aux tailles des plants. Si l'on tient compte de ces dernières, l'analyse de covariance ne montre pas de différence significative entre les pontes sur les différentes lignées. Des substituts de feuilles ont été créés de façon à faire varier les paramètres de taille tout en maintenant constants les autres stimuli de la plante: pour des plantes, dont le diamètre à la base variait de 1 à 4 mm et la hauteur de 100 à 350 mm, seul le diamètre a significativement influé sur la ponte. Les pontes sur les plantes hors de ces dimensions n'ont pu être expliquées par les seules différences de diamètre. Comme les paysans des principales régions productrices d'oignons d'Europe et des U.S.A. font des bénéfices importants avec la culture d'oignons précoces, ces lignées, sélectionnées par mégarde pour leur développement lent, ne sont probablement pas une bonne source de ‘résistance’ à la mouche de l'oignon. Cependant, ces résultats soulignent la nécessité de tenir autant compte de la taille de la plante que de son chimisme ou de sa texture lors de l'évaluation et de la création de cultivars résistants.
    Notizen: Abstract When gravid onion fly females, Delia antiqua (Meigen) (Diptera: Anthomyiidae) were presented in laboratory choice test with 6-week-old plants of a susceptible cultivar and of onion breeding lines selected for resistance, mean numbers of eggs laid ranged from 34.8 to 1.6 eggs per plant. Differences in ovipositional responses were mirrored by differences in plant size. Analysis of covariance revealed no significant differences in ovipositional responses to breeding lines when differences in size were taken into account. Foliar surrogates were developed so that single size parameters could be varied while holding all other plant stimuli constant. Tests using these surrogates revealed that among plants with basal diameters of 1 to 4 mm and heights of 100 to 350 mm, diameter alone significantly influenced responses of ovipositing females. Ovipositional responses to plants beyond this size range could not be explained strictly by diameter differences. These results underscore the necessity of considering plant size as well as plant chemistry and texture in efforts to evalute and design resistant cultivars.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 38 (1985), S. 151-155 
    ISSN: 1570-7458
    Schlagwort(e): Onion maggot ; onion fly ; Delia antiqua ; feeding preference ; Allium cepa ; plant nitrogen ; insect/plant interactions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract When given a choice of feeding sites in laboratory arenas, Delia antiqua (Meigen) larvae exhibited a 3: 1 bias for internal vs outer sections of onion bulbs and distributed themselves non-randomly among identical preferred onion sections. Larval clustering did not appear to be correlated with increased fitness in the laboratory; larval development was identical across the range of densities from 1 to 50 larvae per onion. Larvae feeding on preferred internal sections developed 14% faster, were 38% heavier upon pupation, and were two times more likely to survive to the adult stage than larvae feeding on outer sections. D. antiqua larval food preference was therefore positively correlated with increased fitness.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 47 (1979), S. 1-11 
    ISSN: 1432-0533
    Schlagwort(e): Experimental Concussion ; Peroxidase, neuronal uptake ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Neuronal inundation with i.v. infused horseradish peroxidase was studied following concussive brain injury by means of both light and electron microscopy. In animals sustaining mechanical brain injury of insufficient intensity as to elicit either microscopic intraparenchymal hemorrhage or other neuropathological change, yet of sufficient intensity as to provoke a physiological concussive response, vascular peroxidase exudation concomitant with neuronal peroxidase inundation occurred throughout the raphe and reticular core. Initially such inundated neurons were totally flooded with the tracer and as such appeared reminiscent of cells visualized in Golgi preparations. However, over the course of a 24-h period these peroxidase flooded neurons apparently organized the peroxidase into vesicles and vacuoles which assumed a perinuclear position from where the peroxidase ultimately reached both the nucleus und nucleolus. It was remarkable that these events occurred without any evidence of subcellular alteration. We interpret such initial inundation with this protein tracer, its ultimate reorganization, and its nuclear and nucleolar uptake as being consistent with some form of subtle and transient neuronal perturbation. We speculate that as such this neuronal perturbation may constitute a morphological correlate of the concussive episode.
    Materialart: Digitale Medien
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  • 4
    ISSN: 1432-0533
    Schlagwort(e): Postischemic recirculation ; Complete cerebral ischemia ; Ischemic neuronal injury ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The neuronal response to complete cerebral ischemia (CCI) of 5–15 min duration was evaluated at the light and electron microscopic level subsequent to postischemic recirculation periods of up to 60 min. Following postischemic reperfusion, the homogeneous neuronal changes characteristic of permanent CCI were modified into a heterogeneous pattern of selectively vulnerable neuronal responses. Four basic types of neuronal injury were represented within this heterogeneous neuronal population. The Type I neuronal response was most numerous and consisted of chromatin clumping, nucleolar condensation and a breakdown of polysomes. This response may represent a reversal of some of the neuronal changes observed after permanent CCI. In addition to the above changes, Type II neurons contained swollen mitochondria and Golgi saccules which appeared as microvacuoles under the light microscope. Type III neurons displayed varying degrees of neuronal shrinkage and numerous swollen mitochondria. Type IV neurons were markedly shrunken and electron-dense with few identifiable subcellular structures. The distribution of Type I neurons was random but the other neuronal responses occurred in “selectively vulnerable” brain regions. The number of Type II, III, and IV neurons increased with extended insult durations but were unaffected by the length of recirculation. Ten minutes of CCI represented the threshold for a significant increase in the number of severely altered neurons. These findings suggest that considerable neuronal injury may be present after 10–15 min of CCI, and the lack of a recirculation period following CCI appears to afford the brain parenchyma an extensive degree of structural protection.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 48 (1979), S. 113-125 
    ISSN: 1432-0533
    Schlagwort(e): Complete cerebral ischemia ; Postischemic recirculation ; Electron microscopy ; Nuclear perturbations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Neuronal, astrocytic, and oligodendrocytic elements in several brain loci of the cat were examined at the light and electron microscopic level immediately after periods of complete cerebral ischemia (CCI) uncomplicated by post-ischemic recirculation. Such CCI episodes ranged from 1.5–25 min duration and were methodically produced in a cat model employing rigorous physiological controls. Subsequent to these CCI insults, morphological alterations occurred in a homogeneous manner within each cell type of all loci examined; however, variation in the temporal onset and magnitude of alterations among the various cell types was observed. With brief ischemic insults all cell nuclei demonstrated pronounced nuclear alterations, while their cytoplasmic organelles displayed minimal change. Chromatin clumping and nucleolar condensation were observed in both neurons and glia subsequent to 1.5–5 min of CCI, respectively. With increasing durations of CCI such changes were more dramatic and conspicuous alterations of the cytoplasmic organelles were observed. On the basis of extensive morphological analyses the present study illustrates that nuclear alterations are the first to occur subsequent to CCI. The homogeneity of neuronal involvement seen subsequent to CCI uncomplicated by post-ischemic recirculation is inconsistent with the “selective vulnerability” purported to occur by others. The significance of this inconsistency remains to be assessed; yet, the suggestion is advanced that post-ischemic recirculation may be a factor in the genesis of such vulnerability.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 90 (1995), S. 1158-1163 
    ISSN: 1432-2242
    Schlagwort(e): Triticum aestivum ; Puccinia graminis ; Aneuploid ; Cytogenetics ; Monosomics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The chromosomal locations of genes for resistance to stem rust (Puccinia graminis Pers.: Pers. f. sp. tritici Eriks. & E. Henn.) in the wheat (Triticum aestivum L.) cultivar ‘Waldron’ (WDR) were determined by monosomic analyses. Wheat lines WDR-B1, -C2, -E4, and -F1,which have single genes for resistance to stem rust derived previously from WDR sel. ‘Little Club’, were crossed onto a complete set of 21 ‘Chinese Spring’ monosomics. The F2 and backcross-F1 (BC1F1) seedlings from each of the 84 crosses were tested for reaction to culture 111-SS2 (CRL-LCBB) of stem rust, and a few selected segregants were analyzed cytologically for chromosome number. The F2 from 2 crosses of WDR-C2, -E4 and -F1 and the BC1F1 from 2 crosses of WDR-F1 were tested also with culture Or11c (CRL-QBCN). Significant deviations from disomic ratios towards monosomic ratios in the F2 and BC1F1 were used to determine which chromosomes carried the genes for resistance. Cytological analyses of certain BC1F1 and susceptible F2 plants were used to help identify the location of the genes for rust resistance. WDR-B1 has a gene, herein designated Sr41, for resistance on chromosome 4D. WDR-C2 has a gene on chromosome 7 A that may be the same as one previously designated SrWld2. WDR-E4 has a gene on chromosome 2A, possibly SrWld1, which is effective against most or all North American stem rust cultures. WDR-F1 has a gene on chromosome 6B that is the same as or similar to Sr11.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 90 (1995), S. 1164-1168 
    ISSN: 1432-2242
    Schlagwort(e): Triticum aestivum ; Puccinia graminis ; Allelism ; Inheritance ; Segregation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The Triticum aestivum L. cultivar ‘Waldron’ has long lasting resistance to most North American stem rust (Puccinia graminis Pers.:Pers. f. sp. tritici Eriks. and E. Henn.) isolates. The objective of this research was to develop wheat lines monogenic for resistance to stem rust from ‘Waldron’ using allelism tests and tests for reaction to a series of ten stem rust cultures having a range of virulences. Twelve lines homozygous for single resistance genes were selected as parents of a diallel cross to test for allelism among genes for resistance. We identified 6 lines or groups of lines (WDR-A1, the WDR-B1 and WDR-B2 group, the WDR-C1 and WDR-C2 group, WDR-D1, the WDR-E1, WDR-E2, WDR-E3, and WDR-E4 group, and WDR-F1) that carried different single genes for resistance from ‘Waldron’. A seventh line (WDR-G1) probably has two genes for resistance, one in common with WDR-C1 and WDR-C2. The gene in the WDR-E group is probably the same as SrWld1, and the one in WDR-F1 the same as Sri11. ‘Waldron’ probably has two or more genes for resistance to stem rust that previous genetic studies did not detect.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 26 (1977), S. 103-112 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; hybrid wheat ; male sterility ; cross pollination ; seed production
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Several chemicals were evaluated for their gametocidal properties to control pollination in hybrid wheat (Triticum aestivum L. em Thell.) seed production. In a preliminary study, four chemicals were applied to three cultivars of spring wheat at two application times. RH-532 was the most effective of the four gametocides, reducing fertility to a 0 10% level for all three cultivars. In a second experiment, RH-532 was applied to one cytoplasmic male-sterile and three normal spring wheats at four rates (0.56, 1.12, 2.24, and 4.48 kg/ha) and at two times of application. Alternate strips of pollinator were planted throughout the experiment. All treatments decreased fertility. plant height, and spike length of the three normal wheats. RH-532 did not inhibit spike emergence of two semidwarf cultivars or one of conventional height. Cultivars did not respond similarly to treatments. Yields of cross-pollinated seed were only 1 21% of the normal yield when fertility levels on treated plants reached 0 10%. Hybrid seed content of the harvested seed ranged from 2 55%. On the treated male-sterile line, yield was significantly reduced in comparison with the open-pollinated check. Inhibitory properties of this chemical suppressed the fertilization potential of the female as well as inducing male sterility. The differential response of genotypes to treatments indicates that cultivars should be screened for male and female sensitivity to this chemical. If differential sensitivity is found, breeding and selection to improve this trait may be possible. Different environmental conditions may alter the response of cultivars to this chemical, with less effect on the female structures.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 10 (1984), S. 1477-1488 
    ISSN: 1573-1561
    Schlagwort(e): Delia antiqua ; onion fly ; Diptera ; Anthomyiidae ; food attractants ; host attractants ; microbial attractants ; Klebsiella pneumoniae ; bacteria ; Allium ; onion ; garlic ; chive
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Of various chopped vegetables tested,Allium spp. high in propyl-containing alkyl sulfides (e.g.,cepa group) caught the most onion flies in trapping tests in the field. Fly catches to chopped onion increased with bait quantity. Attractancy of chopped onion changed dramatically during aging in the field; catch increased over the first few days, peaked at ca. fivefold over fresh material by 3–5 days, and then declined sharply. This age-dependent increase in attraction was not seen for garlic (known to have antimicrobial properties) nor with chopped onion mixed with chopped garlic. These data suggested that attraction of onion flies to onions was strongly influenced by microbial activity associated with decomposing onions. The bacteriumKlebsiella pneumoniae was identified as a major colonizer of onions maximally attractive to onion flies. This increased attraction is not due to the previously reported microbially produced volatiles ethyl acetate and tetramethyl pyrazine.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 11 (1985), S. 435-440 
    ISSN: 1573-1561
    Schlagwort(e): Delia (Hylemya) antiqua ; Diptera ; Anthomyiidae ; onion fly ; onion maggot ; tube trap ; insect attractants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Responses of onion flies,Delia antiqua, to known attractants were measured in the laboratory with a novel tube-trap bioassay. The relative numbers of flies caught in tube traps baited with enzymatic yeast hydrolysate, brewer's yeast, andn-dipropyl disulfide were similar to those obtained previously with cone traps in the field. Changing the shape of the bioassay cage from a cuboid to a cylinder decreased the experimental error obtained from analysis of variance, as did rotating the floor of the circular cage. This bioassay should be useful in evaluating attractants for other insects that orient along the substrate.
    Materialart: Digitale Medien
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