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  • 1
    ISSN: 1570-7458
    Keywords: Coreidae ; Hemiptera ; phytotoxicoses ; saliva ; stylet sheath ; sucrase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the saciform, principal salivary glands ofMictis profana (Fabr.) (Coreidae: Heteroptera, Pentatomorpha), the contents of all lobes other than the posterior form gels consistent with their contributing to the solidifying saliva (stylet sheath); the posterior lobe secretes most if not all of a sucrose-hydrolysing enzyme that occurs in the nongelling (watery) saliva. Evidence for the occurrence of such an enzyme in the saliva of other coreids is presented. That inM. profana has a pH optimum near neutral and a substrate specificity consistent with sucrase (sucrose α-D-glucohydrolase, EC 3.2.1.48) as distinct from plant invertase (β-D-fruccofuranosidase, EC 3.2.1.26). Apart from some maltose-hydrolysing activity in the salivary glands, also consistent with sucrase, no other carbohydrases and neither proteinase nor lipase were detected. Phosphatases were found in gland extracts but not in secreted saliva. The saliva contains catechol oxidase (EC 1.10.3.1) from the accessory gland and ducts. Topical application of pilocarpine caused individualM. profana to secrete up to 58 μl watery saliva which showed continuous and independent variation of sucrase activity (up to ca 0.012 Units/μl) and pH (6–8), although high sucrase content tended to coincide with high pH. Total protein varied up to 10 μg/μl, and free amino acids up to 1.8 μg/μl leucine eq. Of the many proteins and/or protein subunits separable by electrophoresis of gland contents and saliva, four had sucrase activity, the most mobile with MW ca 66 000. TLC indicatedinter alia phenyl alanine and tyrosine, but no DOPA nor other diphenolic substrates of the catechol oxidase in the watery saliva. The soluble components of the saliva, which also has marked surfactant properties, are discussed in relation to the feeding process of coreids and the characteristic lesions they produce in their food plants.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 73 (1994), S. 163-173 
    ISSN: 1570-7458
    Keywords: Coreidae ; saliva ; osmotic pump ; phytotoxicoses ; sucrase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Species of Coreidae (Heteroptera) cause ‘water soaked’ lesions in their food plants. Such insects typically feed from parenchyma in and surrounding vascular tissues and also cause acropetal wilting and necrosis of small diameter shoots. Feeding byMictis profana (Fabr.) in South Australia on the shoots ofAcacia iteaphylla F. Muell. ex Benth. was found to cause a local, concurrent increase in both water content and free amino acid concentration, consistent with phloem unloading. Coreids, unlike other groups of phytophagous Heteroptera, secrete a salivary sucrase (α-D-glucohydrolase, EC 3.2.1.48) as probably the sole salivary carbohydrase, and tissues attacked byM. profana showed more sucrose hydrolysing activity than unattacked. The salivary enzyme is postulated to cause unloading of solutes into the apoplast due to the osmotic effects of conversion of endogenous sucrose to glucose and fructose, allowing the insect to suck the leaked contents of many cells from a single locus. The term ‘osmotic pump feeding’ is proposed for such a process. In demonstrations of its feasibility, infiltration of shoots with mixtures of glucose and fructose stoichiometrically equivalent to isosmotic sucrose increased the amounts of tissue sap and amino acid that could be sucked from the tissues; similarly, invertase and 1 M sugars forced into the extracellular space of stem sections increased the amino acids offloaded into the bathing solutions.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of volcanology 56 (1994), S. 193-206 
    ISSN: 1432-0819
    Keywords: Key words: Fractals ; lava ; rheology ; remote sensing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract. This study aims at quantifying the effect of rheology on plan-view shapes of lava flows using fractal geometry. Plan-view shapes of lava flows are important because they reflect the processes governing flow emplacement and may provide insight into lava-flow rheology and dynamics. In our earlier investigation (Bruno et al. 1992), we reported that flow margins of basalts are fractal, having a characteristic shape regardless of scale. We also found we could use fractal dimension (D, a parameter which quantifies flow-margin convolution) to distinguish between the two endmember types of basalts: a′a (D: 1.05–1.09) and pahoehoe (D: 1.13–1.23). In this work, we confirm those earlier results for basalts based on a larger database and over a wider range of scale (0.125 m–2.4 km). Additionally, we analyze ten silicic flows (SiO2: 52–74%) over a similar scale range (10 m–4.5 km). We note that silicic flows tend to exhibit scale-dependent, or non-fractal, behavior. We attribute this breakdown of fractal behavior at increased silica contents to the suppression of small-scale features in the flow margin, due to the higher viscosities and yield strengths of silicic flows. These results suggest we can use the fractal properties of flow margins as a remote-sensing tool to distinguish flow types. Our evaluation of the nonlinear aspects of flow dynamics indicates a tendency toward fractal behavior for basaltic lavas whose flow is controlled by internal fluid dynamic processes. For silicic flows, or basaltic flows whose flow is controlled by steep slopes, our evaluation indicates non-fractal behavior, consistent with our observations.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of volcanology 56 (1994), S. 193-206 
    ISSN: 1432-0819
    Keywords: fractals ; lava ; rheology ; remote sensing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract This study aims at quantifying the effect of rheology on plan-view shapes of lava flows using fractal geometry. Plan-view shapes of lava flows are important because they reflect the processes governing flow emplacement and may provide insight into lava-flow rheology and dynamics. In our earlier investigation (Bruno et al. 1992), we reported that flow margins of basalts are fractal, having a characteristic shape regardless of scale. We also found we could use fractal dimension (D, a parameter which quantifies flow-margin convolution) to distinguish between the two endmember types of basalts: a′ a (D: 1.05–1.09) and pahoehoe (D: 1.13–1.23). In this work, we confirm those earlier results for basalts based on a larger database and over a wider range of scale (0.125 m–2.4 km). Additionally, we analyze ten silicic flows (SiO2: 52–74%) over a similar scale range (10 m–4.5 km). We note that silicic flows tend to exhibit scale-dependent, or non-fractal, behavior. We attribute this breakdown of fractal behavior at increased silica contents to the suppression of small-scale features in the flow margin, due to the higher viscosities and yield strengths of silicic flows. These results suggest we can use the fractal properties of flow margins as a remote-sensing tool to distinguish flow types. Our evaluation of the nonlinear aspects of flow dynamics indicates a tendency toward fractal behavior for basaltic lavas whose flow is controlled by internal fluid dynamic processes. For silicic flows, or basaltic flows whose flow is controlled by steep slopes, our evaluation indicates non-fractal behavior, consistent with our observations.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-5036
    Keywords: breeding ; chromosome ; copper ; copper-efficiency ; Triticum aestivum ; wheat-rye
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A greenhouse study was conducted to determine the Cu-efficiency of 5A/5RL wheat-rye translocation lines and nine wheat genotypes grown in a Cu-deficient orthic dark grey chernozemic soil. The soil used was characterized by pH 5.4 and 0.48 μg Cu g−1 soil (DTPA), and was obtained from a known Cu-deficient site at Stony Plain, Central Alberta. Twelve genotypes (three 5A/5RL wheat-rye translocation lines and nine wheat cultivars) and two Cu treatments (soil amended with 145 μg Cu kg−1 soil, and non-amended) were used. The efficiency for Cu use was evaluated for grain yield and yield components. 5A/5RL wheat-rye translocation lines individually and as a group showed significantly (p〈0.05) higher grain yield both in +Cu and −Cu treatments compared to wheat genotypes without the wheat-rye chromosome translocation. 5A/5RL wheat-rye translocation lines demonstrated Cu-efficiency ranging from 70–127% for grain yield. Only two wheat cultivars (Kenya Leopard and Columbus) showed comparable efficiency (70 and 76% respectively). Wheat cultivars Kwale, Kenya Tausi, Roblin, Katepwa, Park, Oslo and Biggar showed low Cu-efficiency (10–36%). The study confirms that the 5A/5RL wheat-rye translocation confers useful levels of Cu-efficiency to wheat, that can be used as an additional source of variability in breeding programs. ei]L V Kochian
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-5060
    Keywords: Triticum aestivum ; wheat ; anther culture ; callus initiation ; cytoplasm ; cytoplasmic male sterility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Nuclear and cytoplasmic factors affect tissue culture response in wheat (Triticum aestivum), and cytoplasmic male sterility may enhance callus initiation in anther culture. Three wheat nuclear genotypes, each in normal and two alien cytoplasms conferring cytoplasmic male sterility, were evaluated for callus initiation frequency in anther culture. Nuclear genotype had the greatest effect on callus initiation, but cytoplasm and nucleus X cytoplasm interaction also produced significant effects. The nuclear genotype of ‘Chris’ outperformed ‘Butte’ and ‘Coteau’ in all cytoplasms. Ordinary wheat and Triticum timopheevi cytoplasms outperformed Aegilops speltoides cytoplasm. Cytoplasmic male sterility did not increase callus initiation. This suggests manipulating the nuclear genotype is the best strategy for improving the capacity of wheat to initiate callus in anther culture.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 48 (1990), S. 1-8 
    ISSN: 1573-5060
    Keywords: Triticum aestivum ; wheat ; protein accumulation ; plant protein ; protein estimation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Better understanding of the physiological and genetic basis of wheat grain protein will contribute to breeding efforts for this characteristic. This study provides information about plant protein distribution in high and low grain protein winter wheats (Triticum aestivum L.) at different growth stages and its relation to grain protein. Field experiments involved two winter wheats with high grain protein, ‘Redwin’ and ‘Lancota’, and two with low grain protein, ‘Centurk’ and ‘Brule’ in two years. Protein content in the head, the upper three leaves, the first and second leaf, and the peduncle were estimated with Near Infrared Reflectance Spectrophotometer (NIR) at five growth stages. High protein cultivars had higher leaf protein at ripe and higher protein content in the heads at most growth stages than low grain protein cultivars. High protein cultivars had lower protein content in the peduncle than low protein cultivars at ripe. Correlation coefficients between plant-part protein and grain protein ranged from 0.48 to 0.87 for the heads, from −0.45 to −0.79 for the peduncle, and from 0.55 to 0.84 for the leaves. A combination of head, peduncle, and first leaf protein at heading was significantly related to grain protein (R2=0.71). Indirect selection for head, peduncle, and first leaf (flag leaf) protein at heading should result in increased grain protein. Recurrent selection for increased grain protein, with parent selectionbefore anthesis and hybridization should be successful.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-5036
    Keywords: relative addition rate ; relative growth rate ; traditional solution culture ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The relative addition rate (RAR) technique allows the nutritional control of plant relative growth rate (RGR) by the provision of nutrients at exponential supply rates. The technique, however, was developed with technologically sophisticated aeroponic systems. In this paper, we report on experiments used to adapt the RAR technique to a conventional solution culture system. A background concentration requirement of 36 μM nitrogen (N), with other nutrients supplied in proportion to N, was necessary to produce a constant RGR of Triticum aestivum L. (wheat) at a low RAR. Solution pH changes were reduced by increasing the percentage of NH4 in the nitrogen supply, but the plants exhibited dry weight reductions and symptoms of toxicity above 30% NH4. For wheat, a ratio of 25/75 NH4/NO3 was optimum for minimizing pH changes within the nontoxic range. A test of the effectiveness of the RAR technique using this background concentration and NH4/NO3 ratio showed that RGR increased with RAR with a linear slope of 0.55 and an intercept of 0.07 d-1. Although the relationship between growth rate and nutrient supply was less than the one-to-one dependence of RGR on RAR that has been obtained with more sophisticated apparatus, application of the RAR technique to a conventional solution culture system still affords considerable control of RGR and presents a simple method for growing plants at different levels of nutrient stress and at distinct RGRs.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Euphytica 47 (1990), S. 121-130 
    ISSN: 1573-5060
    Keywords: Triticum aestivum ; wheat ; heritability ; protein inheritance ; genotype x environment interaction ; variance components ; indirect selection ; grain protein content ; grain yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Increasing grain protein content is an important wheat breeding goal. Noaman & Taylor (1988b) showed the combination of protein content in the head, peduncle, and flag leaf of winter wheat at heading provided a good estimate for grain protein. The objectives of this research were to apply these results in indirect selection scheme for grain protein improvement and to study the heritability of protein content in these plant parts. Two random winter wheat populations from four parents in double crosses were used in this study. Sixty randon F2-derived F5 and F6 lines were grown in randomized complete block design with 3 replicates in two years. Significant differences for grain yield, grain protein, and vegetative protein content were detected among F5 and F6 lines in both populations. Genotypic and phenotypic correlations between grain protein and vegetative protein were significant and in agreement. Estimates of narrow sense heritability of protein content using variance components method ranged from 0.46 to 0.94 for leaf 2 and head in population 1, and from 0.63 to 0.89 for peduncle and head in population 2. Correlation coefficients (r) between predicted and observed grain protein ranged from 0.50 to 0.88 and from 0.37 to 0.84 in populations 1 and 2, respectively. The highest r was obtained from the combination of head, peduncle, and flag leaf protein at heading. Correlation between protein in plant parts and grain yield was small and not significant. The high heritability of vegetative protein at heading allows the identification of genotypes before pollination which are likely to produce high grain protein. Indirect selection for head, peduncle, and flag leaf protein should result in increased grain protein without yield reduction noted in other breeding schemes.
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  • 10
    ISSN: 1573-5036
    Keywords: aluminium resistance ; doubled-haploid lines ; near-isogenic lines ; root exudate polypeptide ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We have made use of a genetic approach to develop homozygous, near-isogenic germplasm for investigating aluminium (Al) resistance in Triticum aestivum L. A conventional backcross program was used to transfer Al resistance from the Al-resistant cultivar, Maringa, to a locally-adapted, Al-sensitive cultivar, Katepwa. At the third backcross stage, a single, resistant isoline (Alikat = Katepwa*3/Maringa) was chosen on the basis of superior root growth after 14 days of exposure to a broad range of Al concentrations (0 to 600 µM). Genetic analysis of doubled-haploid lines (DH) developed from this isoline suggested that resistance is controlled by a single dominant gene. Crosses between DH Alikat and DH Katepwa yielded an Al-resistant F1 population. Backcrossing this F1 population to DH Katepwa produced a population which segregated 1:1 for Al resistance, while selfing produced a population segregating 3 : 1 for Al resistance. Under conditions of Al stress, Al-resistant F2 plants released a suite of novel low molecular weight polypeptides into the rhizosphere. One of these polypeptides (23 kD) shows substantive Al-binding capacity and segregates with the resistant phenotype. While the precise mechanisms that mediate Al resistance are still unknown, this research has provided support for a possible role of the 23 kD exudate polypeptide in mediating resistance to Al. To more fully understand the role that this polypeptide plays in Al-resistance, we are attempting to clone this gene from microsequence data obtained from purified protein.
    Type of Medium: Electronic Resource
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