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  • Artikel  (106)
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  • 1
    Digitale Medien
    Digitale Medien
    DNA in wheat seeds from European archaeological sites (1994)
    Springer
    Cellular and molecular life sciences 50 (1994), S. 571-575 
    Details
    ISSN: 1420-9071
    Schlagwort(e): Ancient DNA ; archaeobotany ; carbonized grain ; DNA sequences ; glutenin alleles ; seed proteins ; Triticum ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract We have used hybridization analysis to detect ancient DNA in wheat seeds collected from three archaeological sites in Europe and the Middle East. One of these samples, carbonizedT. spelta dated to the first millennium BC, has yielded PCR products after amplification with primers directed at the leader regions of the HMW (high molecular weight) glutenin alleles. Sequences obtained from these products suggest that the DNA present in the Danebury seeds is chemically damaged, as expected for ancient DNA, and also indicate that it should be possible to study the genetic variability of archaeological wheat by ancient DNA analysis. Finally, we describe a PCR-based system that enables tetraploid and hexaploid wheats to be distinguished.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01921727
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  • 2
    Digitale Medien
    Digitale Medien
    Using hydrophilic polymers to control nutrient release (1994)
    Springer
    Nutrient cycling in agroecosystems 38 (1994), S. 53-59 
    Details
    ISSN: 1573-0867
    Schlagwort(e): controlled-release fertilizer ; gel ; iron ; manganese ; nitrogen ; polyacrylamide
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Using diverse technological approaches, many types of delivery devices have been used to supply plant nutrients at a controlled rate in the soil. One new approach is the use of hydrophilic polymers as carriers of plant nutrients. These polymers may be generally classified as 1) natural polymers derived from polysaccharides, 2) semi-synthetic polymers (primarily cellulose derivatives), and 3) synthetic polymers. By controlling the reaction conditions when forming the polymers, various degrees of cross-linking, anionic charge, and cationic charge can be added, thereby changing their effectiveness as fertilizer carriers. When fertilizer-containing solutions are mixed with hydrophilic polymers to form a “gel” prior to application in the soil, the release of soluble nutrients can be substantially delayed compared with soluble fertilizer alone. The effectiveness of a specific controlled-release polymeric system is determined in part by its specific chemical and physical properties, its biodegradation rate, and the fertilizer source used. Addition of some polymers with nutrients has been shown to reduce N and K leaching from well-drained soils and to increase the plant recovery of added N, P, Fe, and Mn in some circumstances
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750062
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  • 3
    Digitale Medien
    Digitale Medien
    Land application of poultry litter and water quality in Oklahoma, U.S.A. (1994)
    Springer
    Nutrient cycling in agroecosystems 40 (1994), S. 165-173 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Animal manure ; eutrophication ; ground water ; nitrogen ; phosphorus ; surface runoff
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract With the rapid growth of the poultry industry in Oklahoma, U.S.A., more litter is applied to farm land. Thus, information is required on the impact of applications on regional soil and water resources. The effect of soil and poultry litter management on nitrogen (N) and phosphorus (P) loss in runoff and subsurface flow from four 16 m2 plots (Ruston fine sandy loam, 6 to 8% slope) was investigated under natural rainfall. Plots under Bermudagrass (Cynodon dactylon) received 11 Mg litter ha−1, which amounts to contributions of approximately 410 kg N and 140 kg P ha−1 yr−1. In spring, litter was broadcast on 3 of the plots; the upper half of one and total area of the other two. One of the total-area broadcast plots was tilled to 6 cm, the other remained as no till. The fourth plot served as a control. Relative to the control, litter application increased mean concentrations of total N and total P in runoff during the 16-week study for no-till (15.4 and 5.8 mg L−1) and tilled treatments (16.7 and 6.1 mg L−1). However, values for the half-area application (5.6 and 2.0 mg L−1) were similar to the control (5.7 and 1.3 mg L−1). Interflow (subsurface lateral flow at 70 cm depth) P was not affected by litter application; however, nitrate-N concentrations increased from 0.6 (control) to 2.9 mg L−1 (no till). In all cases, 〈 2 % litter N and P was lost in runoff and interflow, maintaining acceptable water quality concentrations. Although litter increased grass yield (8518 kg ha−1) compared to the control (3501 kg ha−1), yields were not affected by litter management. An 8-fold increase in the plant available P content of surface soil indicates long-term litter management and application rates will be critical to the environmentally sound use of this nutrient resource.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750462
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  • 4
    Digitale Medien
    Digitale Medien
    Assessing risk associated with N fertilizer recommendations in the absence of soil tests (1994)
    Springer
    Nutrient cycling in agroecosystems 40 (1994), S. 175-183 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Nitrogen response ; on-farm research ; risk ; probability ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In many developing countries, fertilizer recommendations must be made in the absence of plant and soil analyses. When the region is variable in terms of soils, weather, and magnitude of response to fertilizer, a recommendation is likely to involve a high degree of risk for the farmer. Quantification of such risk is key to developing appropriate recommendations for the farmer. However, most methodologies generally used in analyzing fertilizer trials do not allow adequate quantification, especially as a continuous function, of the risk associated with a given recommendation. Three years of on-farm trials conducted in the High Valley of Mexico were used to evaluate different methodologies for generating N fertilization recommendations and their associated risk for wheat (Triticum aestivum) production in the absence of soil tests. When the traditional approach, using average yield responses or separate trial results, was used, an economic optimum was identified, but it was not possible to quantify the associated risk. In contrast, however, by using a combination of response surface methodology and simple probability analysis, the risk associated with any given recommendation was developed, even under the highly variable conditions of the study zone. The approach uses a treatment difference matrix (developed using average yield differences between a treatment and the zero N (0N) check) and its associated standard deviation over locations. From the matrix, an equation (being a function of N rate and relative grain:N price ratios) was developed that shows the probability of outperforming the 0N check for the economic optimum rate.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750463
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  • 5
    Digitale Medien
    Digitale Medien
    Response of ensete (Ensete ventricosum W.) to mineral fertilizers in southwest Ethiopia (1994)
    Springer
    Nutrient cycling in agroecosystems 37 (1994), S. 107-113 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Ensete ventricosum ; fertilizer response ; nitrogen ; phosphorus ; potassium ; sulphur ; starch
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Ensete (Ensete ventricosum W. Cheesm.) is a root crop which stores starch in the root and in the lower part of the stem. It is grown in the southwest of Ethiopia and due to its drought resistance, it is of outstanding importance for the supply of food to the local population. Until now virtually nothing is known about the response of Ensete to fertilizer application. Field trials carried out on three representative soils in Ethiopia showed that Ensete biomass yields were increased significantly on all three soils by nitrogen and phosphorus application. Potassium had only marginal effect on biomass growth but favourably influenced starch production. Sulfate application had no major impact on growth and starch yield. The yield response was well related to the level of available nutrients in the soil, as determined by electroultrafiltration (EUF). Leaf analysis provided preliminary evidence that optimum levels of N, P, and K may be 3.8%, 0.3%, and 4.8%, respectively.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00748551
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  • 6
    Digitale Medien
    Digitale Medien
    The effect of nitrogen catch crop species on the nitrogen nutrition of succeeding crops (1994)
    Springer
    Nutrient cycling in agroecosystems 37 (1994), S. 227-234 
    Details
    ISSN: 1573-0867
    Schlagwort(e): catch crop ; mineralization ; nitrogen ; plant species ; residual effects ; soil depletion ; winter hardiness
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Ten widely different plant species were compared for their ability to reduce soil mineral nitrogen levels in the autumn and their ability to improve the nitrogen nutrition of the succeeding crop. The species included monocots and dicots, crops that survived the winter (persistent) or were winter killed (non-persistent) as well as legumes and non legumes. Their ability to reduce soil mineral nitrogen content was dependent on both root depth and persistency of the crops in the autumn. For non-persistent catch crops most of the mineralization of plant nitrogen occurred during the winter, and for some of these so early as to allow leaching of some mineralized nitrogen. For persistent crops most of the mineralization occurred shortly after incorporation in the spring. The effect of the catch crops on nitrogen uptake by the succeeding barley crop varied from 13 to 66 kg N ha−1 and the differences between the crops could not be related to any single character, but to a combination of root depth, persistency, plant nitrate accumulation, and depletion of the soil mineral nitrogen pool in spring.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00748941
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  • 7
    Digitale Medien
    Digitale Medien
    Effect of soil pH on the requirement for water-soluble phosphorus in triple superphosphate fertilizers (1994)
    Springer
    Nutrient cycling in agroecosystems 40 (1994), S. 207-214 
    Details
    ISSN: 1573-0867
    Schlagwort(e): available P ; citrate insoluble P ; phosphorus sources ; triple superphosphate ; Triticum aestivum ; water soluble P ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A greenhouse study was conducted to determine if soil pH affects the requirement for water-soluble P and the tolerance of water-insoluble impurities in TSP fertilizers. Two commercial TSP fertilizers were selected to represent a range in phosphate rock sources and impurities. Phosphate fertilizer impurities were isolated as the water-washed fraction by washing whole fertilizers with deionized water. TSP fertilizers with various quantities of water-soluble P (1.2 to 99% water-soluble P) were simulated by mixing the water-washed fertilizer fractions or dicalcium phosphate (DCP) with reagent-grade monocalcium phosphate (MCP). The fertilizers were applied to supply 40 mg AOAC available P kg−1 to a Mountview silt loam (fine-silty, siliceous, thermic Typic Paleudults). Wheat (Triticum aestivum (L.)) was harvested at 49 and 84 days after planting. Soil pH values at the final forage harvest were 5.4±0.16 and 6.4±0.15. At a soil pH of 5.4, the TSP fertilizers required only 37% water-soluble P to reach maximum yields while at pH 6.4 the fertilizers required 63% water-soluble P. Results of this study show that higher levels of water -insoluble P can be tolerated in TSP fertilizers when applied to acid soils. Phosphorus uptake was not affected by soil pH, but for the mixtures containing the fertilizer residues the source having the lowest level of Fe and Al had a higher relative agronomic effectiveness.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750467
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  • 8
    Digitale Medien
    Digitale Medien
    Wheat growth from phosphorus fertilizers as affected by time and method of application in soil with an acidic subsurface layer (1994)
    Springer
    Nutrient cycling in agroecosystems 39 (1994), S. 77-82 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Acidic subsurface layer ; application rate ; North Carolina phosphate rock ; placement method ; time of application ; triple superphosphate ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Using soils with an acidic subsurface layer, three glasshouse experiments were carried out to evaluate the effect of placement method and application rate of triple superphosphate (TSP) and North Carolina phosphate rock (NCPR) on dry matter (DM) yields. Time of application of NCPR on DM yield response of wheat was also studied. For Experiment 1, soil was collected in depth intervals of 0–2; 4–6; 6–8; and 8–10 cm from a red earth (chromic luvisol). The treatments included two P sources (TSP and NCPR), three placement methods (broadcast, banded or mixed into the subsurface layer, 6–8 cm), and six application rates. In this P deficient soil with an acidic subsurface layer, there was relatively little effect of application method of TSP on wheat yield responses. The maximum dry matter yield responses for broadcast, band and mix application methods was 30, 42 and 50 %, respectively. Responses to NCPR broadcast, band and mix methods were 20, 9 and 44 %, respectively. Mixing NCPR into to acidic subsurface layer produced yields similar to those from TSP although a higher application rate of P as NCPR was needed to achieve this outcome. Treatments for Experiments 2 and 3 were time of application of NCPR (0 and 30 days before sowing) and rate of application of NCPR (0 and 40 mg P/pot). In Experiment 2 (same soil as Experiment 1) application of NCPR prior to sowing, resulted in higher Colwell P concentration than when applied at sowing, but time of application had no effect on final DM yields. Experiment 3 used a red podzolic (chromic luvisol) soil which had a lower P-status, was more acid and had a lower exchangeable Ca2+ concentration than the red earth. Application of NCPR prior to sowing resulted in lower DM yield than when it was applied prior to sowing.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750159
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  • 9
    Digitale Medien
    Digitale Medien
    Application of15N-labelled urea to sugar cane through a drip-irrigation system in Mauritius (1994)
    Springer
    Nutrient cycling in agroecosystems 39 (1994), S. 223-228 
    Details
    ISSN: 1573-0867
    Schlagwort(e): drip-fertigation ; efficiency ; nitrogen ; sugar cane ; uptake ; yield
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Nitrogen (N) fertilizer use efficiency by sugar cane in Mauritius rarely exceeds 40%. Since drip-irrigation delivers water uniformly and directly to the root zone with little run-off, application of N via the drip-irrigation system could therefore provide a means of enhancing fertilizer N use by sugar cane. A study was initiated in Mauritius to determine what benefits would accrue from applying urea (120 kg N per ha) to sugar cane through the drip-irrigation network. The data obtained showed that the efficiency of fertilizer N when measured at harvest was nearly doubled by supplying the N daily over 10 to 20 weeks by fertigation. Increased yields of sugar or cane did not, however, accompany the improved N use efficiency. Furthermore, when N was applied through the drip-irrigation network, recovery of N at harvest did not accurately reflect N use efficiency.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750250
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  • 10
    Digitale Medien
    Digitale Medien
    The residual effectiveness of previously applied copper fertiliser for grain yield of wheat grown on soils of south-west Australia (1994)
    Springer
    Nutrient cycling in agroecosystems 39 (1994), S. 11-18 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Copper fertiliser ; nitrogen fertiliser ; residual effectiveness ; Triticum aestivum L. ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The residual effectiveness of copper (Cu) applied 18 to 21 years previously was estimated for grain yield of wheat. In one field experiment, current levels of Cu fertiliser were applied and its effectiveness was compared to that of the same level of Cu applied previously. The effects of nitrogen (N) fertiliser on the Cu concentration in the youngest emerged blade and in the grain, as well as the effects of N levels on the grain yield of wheat, were also studied. Where the recommended level of Cu fertiliser had been applied previously, its residual effectiveness depended on the soil type. On the grey sands over clay and gravelly sands over clay, the residual Cu would last approximately 20 years where wheat is grown in rotation with a legume crop (Lupinus augustifolius L.) and where N fertiliser is applied at high levels (92 kg N ha−1). On the yellow brown sandy earths of the Newdegate district, the residual value was in excess of 30 years. When Cu levels in the soil are marginal, high levels of N applied to wheat crops grown on stubbles of legume crops (high soil N) could suffer from induce Cu deficiency which could reduce grain production. Critical concentrations of Cu in the youngest emerged blade of less than 1.2 mg Cu kg−1 at Gs50–59 would indicate Cu deficiency. Cu concentrations of less than 1.1–1.2 mg Cu kg−1 in the grain suggest that the wheat crop is marginally supplied with Cu. In both situations, Cu fertiliser needs to be applied before the next crop.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750152
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  • 11
    Digitale Medien
    Digitale Medien
    Penicillium bilaji and phosphorus fertilization effects on the growth, development, yield and common root rot severity of spring wheat (1994)
    Springer
    Nutrient cycling in agroecosystems 39 (1994), S. 97-103 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Cochliobolus sativus ; common root rot ; Penicillium bilaji ; phosphorus fertilization ; tillering ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A strain ofPenicillium bilaji Chalabuda (PB) has recently been commercially released as a seed inoculant to increase phosphorus (P) uptake by wheat (Triticum aestivum L.). The purpose of this study was to compare the effects of drill applied P (15 kg P ha−1) with PB seed inoculation on early growth, development, P uptake, and grain yield of ‘Stoa’ spring wheat at four sites in North Dakota. Fertilization with P consistently enhanced early season growth, main stem development, tillering and P uptake. Seed inoculation with PB had little or no effect on these traits. Phosphorus fertilization tended to increase common root rot severity (CRR, incited byCochliobolus sativus (Ito & Kurib) Drechs.), while PB inoculation had no effect. Grain yields were significantly increased by P fertilization at one location. Inoculation with PB also increased grain yield at this location. The reason why PB inoculation increased yield at this location is not evident, as plant growth and P uptake were not enhanced earlier in the season. Averaged across all four sites, PB inoculation increased wheat yields 66 kg ha−1, which is similar to averaged yield responses reported from the Prairie Provinces of Canada.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750908
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  • 12
    Digitale Medien
    Digitale Medien
    Urea management for lowland transplanted rice as affected by application of farmyard manure (1994)
    Springer
    Nutrient cycling in agroecosystems 39 (1994), S. 199-203 
    Details
    ISSN: 1573-0867
    Schlagwort(e): farmyard manure ; floodwater ; nitrogen ; Oryza sativa L. ; partial pressure of ammonia ; urea ; Vietnam
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Farmyard manure (FYM) applied to rice-growing soils can substitute for industrial fertilizers, but little is known about the influence of FYM on the effectiveness and optimal management for industrial N fertilizers. A field experiment was conducted in northern Vietnam on a degraded soil in the spring season (February to June) and summer season (July to November) to determine the effect of FYM on optimal timing for the first application of urea. The experimental design was a randomized complete block with two rates of basal incorporated FYM (0 or 6 Mg ha−1) in factorial combination with two timings of the first application of 30 kg urea-N ha−1 (basal incorporated before transplanting or delayed until 14 to 16 d after transplanting). The FYM was formed by composting pig manure with rice straw for 3 months. Basal incorporation of FYM, containing 23 kg N ha−1, increased rice grain yield in both seasons. The yield increase cannot be attributed to reduced ammonia loss of applied urea-N, because FYM did not reduce partial pressure of ammonia (pNH3) following urea application in either season. Basal and delayed applications of urea were equally effective in the absence of FYM, but when FYM was applied rice yields in both seasons were higher for delayed (mean = 3.2 Mg ha−1) than basal (mean = 2.9 Mg ha−1) application of urea. Results suggest that recommendations for urea timing in irrigated lowland rice should consider whether farmers apply FYM.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750247
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  • 13
    Digitale Medien
    Digitale Medien
    Quick-freeze, deep-etch visualization of exocytosis in anterior pituitary secretory cells: localization and possible roles of actin and annexin II (1994)
    Springer
    Cell & tissue research 277 (1994), S. 51-60 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Subcortical actin filaments ; Exocytosis ; Sectetory granules ; Annexin II ; Anterior pituitary secretory cells ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The exocytotic process in the anterior pituitary secretory cells was studied using quick-freeze deep-etch electron microscopy, fluorescein-isothiocyanate-phalloidin staining, heavy meromyosin decoration, and immuno-electron microscopy. The subcortical actin filaments are distributed unevenly in the peripheral cytoplasm. Few secretory granules are seen beneath the plasma membrane in the region where the peripheral cytoplasm is occupied by numerous subcortical actin filaments. On the contrary, in the region free of the subcortical actin filaments, many secretory granules lie in contact with the plasma membrane. Thus, the subcortical actin filaments may control the approach of the secretory granules to the plasma membrane in these cells. The granule and plasma membranes that lie in close proximity are linked by intervening strands. Unfused portions of both membranes remain linked by these strands during membrane fusion and opening. These strands may be involved in membrane contact, fusion and opening during exocytosis. Annexin II (calpactin I) has been demonstrated immunocytochemically to be localized at the contact sites between the granule and plasma membranes, and is therefore a possible component of the intervening strands. Membrane fusion starts within focal regions of both membranes less than 50 nm in diameter. The plasma membrane shows inward depressions toward the underlying granules immediately before fusion. The disappearance of intramembranous particles from the exocytotic site of the membrane has not been observed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00303080
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  • 14
    Digitale Medien
    Digitale Medien
    Effects of illumination and enucleation on substance-P-immunoreactive structures in subcortical visual centers of golden hamster and Wistar rat (1994)
    Springer
    Cell & tissue research 277 (1994), S. 351-361 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Circadian rhythm ; Enucleation ; Optic tectum ; Substance P ; Suprachiasmatic nucleus ; Visual system ; Golden hamster ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The undecapeptide substance P is found in different entities of the visual system that control eye movement and synchronize endogenous rhythms with the light cycle (i.e., superior colliculus, suprachiasmatic nucleus, intergeniculate leaflet). Immunocytochemical methods were used to compare the reactivity to substance P in the brain of five groups of golden hamsters and two groups of Wistar rats: (1) untreated hamsters kept under 14L:10D and sacrificed at noon; (2) identically maintained animals sacrificed at midnight; (3) enucleated animals kept under control conditions; (4) hamsters kept under constant darkness; (5) hamsters kept under the same conditions as the controls, but intraventricularly injected with colchicine. The results obtained in golden hamsters of groups (1) and (3) were compared with findings in Wistar rats treated accordingly [groups (6) and (7)]. Substance P-immunoreactive perikarya were found in the suprachiasmatic nucleus and superior colliculus of hamsters and Wistar rats. Substance P-immunoreactive nerve fibers were abundant in the hypothalamic area ventral to the paraventricular nucleus, in the intergeniculate leaflet, in some thalamic nuclei, and in the superior colliculus. Immunoreactivity to substance P in the suprachiasmatic nucleus and intergeniculate leaflet did not vary among the experimental groups. However, a conspicuous decrease in reactivity to substance P was observed in the superficial layers of the superior colliculus of enucleated hamsters and rats, compared with all other groups. These results indicate that substance P immunoreactivity in the superior colliculus, but not that in the suprachiasmatic nucleus or intergeniculate leaflet, depends on the integrity of the retinal projection.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00327783
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  • 15
    Digitale Medien
    Digitale Medien
    Endocardial endothelium in the rat: junctional organization and permeability (1994)
    Springer
    Cell & tissue research 277 (1994), S. 391-400 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Heart ; Endocardial endothelium ; Capillary endothelium ; Myocardium ; Permeability ; Tight junctions ; Dextran ; Confocal scanning laser microscopy ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Selective permeability of endocardial endothelium has been suggested as a mechanism underlying the modulation of the performance of subjacent myocardium. In this study, we characterized the organization and permeability of junctional complexes in ventricular endocardial endothelium in rat heart. The length of intercellular clefts viewed en face per unit endothelial cell surface area was lower, and intercellular clefts were deeper in endocardial endothelium than in myocardial vascular endothelium, whereas tight junctions had a similar structure in both endothelia. On this basis, endocardia endothelium. might be less permeable than capillary endothelium. However, confocal scanning laser microscopy showed that intravenously injected dextran 10000 coupled to Lucifer Yellow penetrated first the endocardial endothelium and later the myocardial capillary endothelium. Penetration of dextran 10000 in myocardium occurred earlier through subepicardial capillary endothelium than through subendocardial capillary endothelium. Penetration of tracer might thus be influenced by hydrostatic pressure. Dextran of MW 40000 did not diffuse through either endocardial endothelium or capilary endothelium. The ultrastructure of endocardial endothelium may constitute an adaptation to limit diffusion driven by high hydrostatic pressure in the heart. Differences in paracellular diffusion of dextran 10000 between endocardial endothelium and myocardial vessels, may result from differing permeability properties of the endocardium and underlying myocardium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00300211
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  • 16
    Digitale Medien
    Digitale Medien
    Distribution of collagens type I, type III and type V in the pancreas of rat, dog, pig and man (1994)
    Springer
    Cell & tissue research 277 (1994), S. 115-121 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Collagen type I ; Collagen type III ; Collagen type V ; Pancreas dissociation ; Islet isolation ; Dog ; Rat (Wistar) ; Pig ; Man
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. The presence of collagens type I, type III and type V was determined immunohistochemically in pancreatic tissue of rat, pig, dog and man. The reaction to anti-collagen type I is weak (pig, dog) or moderate (rat, man) in the peri-insular region and in the lobar, lobular and acinar septa, whereas the reaction to anti-collagen type III is well developed. In rat and dog, the latter reaction deposit on the lobar and acinar septa is prominent. These elements only show a moderate reaction intensity in pig and man. The peri-insular region displays a weak (rat, dog, man) or very weak (pig) reaction against collagen type III. Anti-collagen type V reacts moderately (rat, dog, man) or weakly (pig) in the lobar and lobular septa. The acinar septa show a moderate (rat, dog, man) or very weak (pig) reaction. This information regarding the types and distribution of the collagenous compounds in pancreatic extracellular matrix could lead to differentiated enzymatic pancreas dissociation and, ultimately, increased islet yield and improved reproducibility of pancreatic islet isolation procedures for transplantation purposes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00303087
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  • 17
    Digitale Medien
    Digitale Medien
    Morphological changes during fiber type transitions in low-frequency-stimulated rat fast-twitch muscle (1994)
    Springer
    Cell & tissue research 277 (1994), S. 363-371 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Fiber-type transition ; Low-frequency stimulation ; Muscle fiber morphology ; Myosin heavy chain isoform ; Satellite cell ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract This study investigates morphological adaptations of rat extensor digitorum longus muscle to chronic low-frequency stimulation (10 Hz, 10 h/d, up to 61±7d). During the early stimulation period (2–4 d), increased basophilia and accumulation of RNA were seen predominantly in type-IIB fibers. Putative satellite cell activation, as indicated by 3H-thymidine incorporation, was also evident during this phase. By 12 d, fiber composition remained unaltered, but there was a decrease in the cross-sectional area of the type-IIB fibers. Following 28 d of low-frequency stimulation, the percentage of type-IIB fibers decreased from 43±3% to 0%, while type-IID fibers increased from 30±3% to 60±6%. The fraction of type-IIA fibers tended to increase (controls 19±3%; stimulated 29±4%), whereas that of the type-I fibers was unaltered (4±1%). At this time, the cross-sectional area of type-IID fibers was unaltered, but that of type-IIA and type-I fibers increased. Further stimulation resulted in a return of type-IID fibers to control levels (23±5%), and a marked increase in type-IIA fibers (45±8%). The percentage of type-I fibers increased from 4±1% to 8±1%. Throughout each stage of chronic stimulation, there was no histological evidence of fiber degeneration and regeneration. These results indicate that, in contrast to the rabbit, chronic low-frequency stimulation-induced fiber conversion in the rat extensor digitorum longus muscle is entirely due to fiber transformation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00327784
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  • 18
    Digitale Medien
    Digitale Medien
    Effects of illumination and enucleation on substance-P-immunoreactive structures in subcortical visual centers of golden hamster and Wistar rat (1994)
    Springer
    Cell & tissue research 277 (1994), S. 351-361 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Circadian rhythm ; Enucleation ; Optic tectum ; Substance P ; Suprachiasmatic nucleus ; Visual system ; Golden hamster ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. The undecapeptide substance P is found in different entities of the visual system that control eye movement and synchronize endogenous rhythms with the light cycle (i.e., superior colliculus, suprachiasmatic nucleus, intergeniculate leaflet). Immunocytochemical methods were used to compare the reactivity to substance P in the brain of five groups of golden hamsters and two groups of Wistar rats: (1) untreated hamsters kept under 14L:10D and sacrificed at noon; (2) identically maintained animals sacrificed at midnight; (3) enucleated animals kept under control conditions; (4) hamsters kept under constant darkness; (5) hamsters kept under the same conditions as the controls, but intraventricularly injected with colchicine. The results obtained in golden hamsters of groups (1) and (3) were compared with findings in Wistar rats treated accordingly [groups (6) and (7)]. Substance P-immunoreactive perikarya were found in the suprachiasmatic nucleus and superior colliculus of hamsters and Wistar rats. Substance P-immunoreactive nerve fibers were abundant in the hypothalamic area ventral to the paraventricular nucleus, in the intergeniculate leaflet, in some thalamic nuclei, and in the superior colliculus. Immunoreactivity to substance P in the suprachiasmatic nucleus and intergeniculate leaflet did not vary among the experimental groups. However, a conspicuous decrease in reactivity to substance P was observed in the superficial layers of the superior colliculus of enucleated hamsters and rats, compared with all other groups. These results indicate that substance P immunoreactivity in the superior colliculus, but not that in the suprachiasmatic nucleus or intergeniculate leaflet, depends on the integrity of the retinal projection.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410050162
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  • 19
    Digitale Medien
    Digitale Medien
    Intra-acrosomal organization of a 90-kilodalton antigen during spermiogenesis in the rat (1994)
    Springer
    Cell & tissue research 277 (1994), S. 61-67 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Acrosome development ; Antigen localization ; Intra-acrosomal migration ; Golgi apparatus ; Spermiogenesis ; Immunocytochemistry ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The localization of an acrosomal protein was studied using a monoclonal antibody MN7 raised against mouse spermatozoa. MN7 specifically recognized the anterior acrosome of several mammalian (mouse, rat, hamster) spermatozoa fixed with paraformaldehyde. An immunoblot study with periodate treatment showed that MN7 recognized a carbohydrate region of a 90 kDa protein in an extract of mouse and rat cauda epididymal spermatozoa. The change in distribution of the MN7 antigen during acrosome development was investigated in the rat testis using the pre-embedding immunoperoxidase technique. The antigen first appeared in the proacrosomic granules of spermatids in steps 1–2. Small vesicles adjacent to the outer acrosomal membrane and the developing acrosomic system were immunoreactive during steps 4–7. The majority of the antigen was then redistributed to the head-cap portion during steps 8–18, and finally restricted to the anterior acrosome in the step 19-spermatid. These results suggest that the antigen is transported to the acrosome by way of the vesicles that originate from the Golgi apparatus during early spermiogenesis, and are then delivered to the final destination within the acrosome by the intra-acrosomal migration during late spermiogenesis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00303081
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  • 20
    Digitale Medien
    Digitale Medien
    Distribution of collagens type I, type III and type V in the pancreas of rat, dog, pig and man (1994)
    Springer
    Cell & tissue research 277 (1994), S. 115-121 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Collagen type I ; Collagen type III ; Collagen type V ; Pancreas dissociation ; Islet isolation ; Dog ; Rat (Wistar) ; Pig ; Man
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The presence of collagens type I, type III and type V was determined immunohistochemically in pancreatic tissue of rat, pig, dog and man. The reaction to anti-collagen type I is weak (pig, dog) or moderate (rat, man) in the peri-insular region and in the lobar, lobular and acinar septa, whereas the reaction to anti-collagen type III is well developed. In rat and dog, the latter reaction deposit on the lobar and acinar septa is prominent. These elements only show a moderate reaction intensity in pig and man. The peri-insular region displays a weak (rat, dog, man) or very weak (pig) reaction against collagen type III. Anti-collagen type V reacts moderately (rat, dog, man) or weakly (pig) in the lobar and lobular septa. The acinar septa show a moderate (rat, dog, man) or very weak (pig) reaction. This information regarding the types and distribution of the collagenous compounds in pancreatic extracellular matrix could lead to differentiated enzymatic pancreas dissociation and, ultimately, increased islet yield and improved reproducibility of pancreatic islet isolation procedures for transplantation purposes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00303087
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  • 21
    Digitale Medien
    Digitale Medien
    Morphological changes during fiber type transitions in low-frequency-stimulated rat fast-twitch muscle (1994)
    Springer
    Cell & tissue research 277 (1994), S. 363-371 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Fiber-type transition ; Low-frequency stimulation ; Muscle fiber morphology ; Myosin heavy chain isoform ; Satellite cell ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. This study investigates morphological adaptations of rat extensor digitorum longus muscle to chronic low-frequency stimulation (10 Hz, 10 h/d, up to 61 ± 7d). During the early stimulation period (2–4 d), increased basophilia and accumulation of RNA were seen predominantly in type-IIB fibers. Putative satellite cell activation, as indicated by 3H-thymidine incorporation, was also evident during this phase. By 12 d, fiber composition remained unaltered, but there was a decrease in the cross-sectional area of the type-IIB fibers. Following 28 d of low-frequency stimulation, the percentage of type-IIB fibers decreased from 43 ± 3% to 0%, while type-IID fibers increased from 30 ± 3% to 60 ± 6%. The fraction of type-IIA fibers tended to increase (controls 19 ± 3%; stimulated 29 ± 4%), whereas that of the type-I fibers was unaltered (4 ± 1%). At this time, the cross-sectional area of type-IID fibers was unaltered, but that of type-IIA and type-I fibers increased. Further stimulation resulted in a return of type-IID fibers to control levels (23 ± 5%), and a marked increase in type-IIA fibers (45 ± 8%). The percentage of type-I fibers increased from 4 ± 1% to 8 ± 1%. Throughout each stage of chronic stimulation, there was no histological evidence of fiber degeneration and regeneration. These results indicate that, in contrast to the rabbit, chronic low-frequency stimulation-induced fiber conversion in the rat extensor digitorum longus muscle is entirely due to fiber transformation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410050163
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  • 22
    Digitale Medien
    Digitale Medien
    Nitrergic innervation and nitrergic cells in arteriovenous anastomoses (1994)
    Springer
    Cell & tissue research 277 (1994), S. 477-484 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Nitric oxide ; Nitrergic nerves ; Arteriovenous anastomoses ; Epithelioid cells ; Man ; Rat (Wistar) ; Rabbit ; Dog
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Nitrergic innervation and nitrergic epithelioid cells were studied in arteriovenous anastomoses of the tongue, ear, eye, and glomus organ of the finger in different species (rat, rabbit, dog, and man), by means of immunohistochemistry for nitric oxide synthase and enzyme histochemistry utilizing the catalytic activity of this enzyme (the NADPH-diaphorase reaction). Nitrergic perivascular fibers of the tongue were concentrated along the arterial tree and were maximal at the arteriovenous anastomoses in all species. Generally, fewer fibers were located around comparable segments of the episcleral eye vasculature. Only a few nitrergic fibers were found in the canine and rabbit ear, and in the glomus organ of the human finger; however, epithelioid cells in the tunica media of arteriovenous anastomoses of these organs were NADPH-diaphorase-positive and were moderately immunoreactive for nitric oxide synthase. In the epithelioid cells, the reaction product of the NADPH-diaphorase could also be demonstrated by transmission electron microscopy. The epithelioid cells were negative for the panneural and neuroendocrine marker PGP 9.5 confirming the myocytotic nature of these nitrergic cells. Thus, nitric oxide might play a role in mediating the vessel tone of arteriovenous anastomoses via nitrergic nerves or epithelioid cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00300220
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  • 23
    Digitale Medien
    Digitale Medien
    Analysis of the efferent projections of the lateral geniculate nucleus with special reference to the innervation of the subcommissural organ and related areas (1994)
    Springer
    Cell & tissue research 277 (1994), S. 437-445 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Subcommissural organ (SCO) ; Lateral geniculate nucleus ; Intergeniculate leaflet ; Circadian system ; Pineal gland ; Photoneuroendocrine aspects ; Phaseolus vulgaris-leucoagglutinin (PHA-L) ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract In order to define central neurons projecting to the subcommissural organ (SCO) and to related areas in the postero-medial diencephalon, Phaseolus vulgaris-leucoagglutinin (PHA-L) was injected into the lateral geniculate nucleus of the rat. PHA-L-labelled neurons send axonal processes medially through the posterior thalamic nuclei and the posterior commissure to the other hemisphere. Branches of fibres originating from this projection form a plexus of nerve terminals in the underlying precommissural nucleus and in the nucleus of the posterior commissure. A small number of PHA-L-immunoreactive nerve fibres penetrate from the precommissural nucleus into the lateral part of the SCO. A few labelled fibres penetrate directly from the posterior commissure into the medial part of the caudal SCO. Most of the PHA-L-immunoreactive fibres occur in the hypendymal layer, although a few terminate near the ependymal cells of the organ. Many labelled fibres are found in the ventricular ependyma adjacent to the SCO, some fibres lying close to the ventricular lumen. These results were obtained only if the tracer was delivered into the intergeniculate leaflet of the lateral geniculate nucleus (IGL). The IGL innervates both the suprachiasmatic nucleus and the pineal organ; the connections between the IGL and the midline structures, including the SCO, suggest that these areas are influenced by the circadian system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00300216
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  • 24
    Digitale Medien
    Digitale Medien
    Endocardial endothelium in the rat: junctional organization and permeability (1994)
    Springer
    Cell & tissue research 277 (1994), S. 391-400 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Heart ; Endocardial endothelium ; Capillary endothelium ; Myocardium ; Permeability ; Tight junctions ; Dextran ; Confocal scanning laser microscopy ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. Selective permeability of endocardial endothelium has been suggested as a mechanism underlying the modulation of the performance of subjacent myocardium. In this study, we characterized the organization and permeability of junctional complexes in ventricular endocardial endothelium in rat heart. The length of intercellular clefts viewed en face per unit endothelial cell surface area was lower, and intercellular clefts were deeper in endocardial endothelium than in myocardial vascular endothelium, whereas tight junctions had a similar structure in both endothelia. On this basis, endocardial endothelium might be less permeable than capillary endothelium. However, confocal scanning laser microscopy showed that intravenously injected dextran 10 000 coupled to Lucifer Yellow penetrated first the endocardial endothelium and later the myocardial capillary endothelium. Penetration of dextran 10 000 in myocardium occurred earlier through subepicardial capillary endothelium than through subendocardial capillary endothelium. Penetration of tracer might thus be influenced by hydrostatic pressure. Dextran of MW 40 000 did not diffuse through either endocardial endothelium or capillary endothelium. The ultrastructure of endocardial endothelium may constitute an adaptation to limit diffusion driven by high hydrostatic pressure in the heart. Differences in paracellular diffusion of dextran 10 000, between endocardial endothelium and myocardial vessels, may result from differing permeability properties of the endocardium and underlying myocardium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00300211
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  • 25
    Digitale Medien
    Digitale Medien
    Early postnatal growth of skeletal muscle blood vessels of the rat (1994)
    Springer
    Cell & tissue research 275 (1994), S. 419-434 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Postnatal growth ; Skeletal muscle ; Blood vessels ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The development of blood vessels during the first three postnatal weeks was studied in the ventral stripe of the spinotrapezius muscle of the rat by use of India ink-gelatine injections, and electron microscopy. The number of terminal arterioles and collecting venules remained unchanged postnatally in the observed area. A remarkable proximodistal gradient of vascular development was apparent: while the basic structure of the hilar vessels remained unchanged in the time studied, the intramuscular arteries and veins matured gradually. More peripherally, gradual maturation of terminal and precapillary arterioles was observed. The capillary endothelium and the pericytes showed immature features, and remained unchanged during the time studied. An intense rebuilding activity was found in the endothelial cells of the growing venules, expressed by various forms of gaps, covered by an intact basal lamina and pericytes. Numerous mast cells and macrophages were found along all vessels. Intramuscular lymphatics were not present prior to the first postnatal week.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318812
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  • 26
    Digitale Medien
    Digitale Medien
    Coexistence of NADPH-diaphorase with vasopressin and oxytocin in the hypothalamic magnocellular neurosecretory nuclei of the rat (1994)
    Springer
    Cell & tissue research 276 (1994), S. 31-34 
    Details
    ISSN: 1432-0878
    Schlagwort(e): NADPH-diaphorase ; Vasopressin ; Oxytocin ; Coexistence ; Hypothalamus ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Coexistence of NADPH-diaphorase with vasopressin and oxytocin was studied in the magnocellular neurosecretory nuclei of the rat hypothalamus by use of sequential histochemical and immunocytochemical techniques in the same sections. Coexistence was found in all the nuclei examined (supraoptic, paraventricular, circular, fornical, and in some isolated neurons located in the hypothalamic area between the paraventricular and supraoptic nuclei). The ratios of neurons expressing both markers (NADPH-diaphorase and vasopressin, NADPH-diaphorase and oxytocin) in each of the nuclei were very similar. Although further studies must be carried out, the partial coexistence found in all nuclei suggests that NADPH-diaphorase is probably not related to general mechanisms involving vasopressin and oxytocin, but rather in specific functions shared by certain hypothalamic neuronal cell populations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00354781
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  • 27
    Digitale Medien
    Digitale Medien
    NADPH-diaphorase-positive nerve fibers associated with motor endplates in the rat esophagus: new evidence for co-innervation of striated muscle by enteric neurons (1994)
    Springer
    Cell & tissue research 276 (1994), S. 23-30 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Esophagus ; Motor innervation ; NADPH-diaphorase ; Enteric nervous system ; Nucleus ambiguus ; Anterograde tracing ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract NADPH-diaphorase histochemistry was combined with demonstration of acetylcholinesterase and immunocytochemistry for calcitonin gene-related peptide to study esophageal innervation in the rat. Most of the myenteric neurons stained positively for NADPH-diaphorase, as did numerous varicose nerve fibers in the myenteric plexus, among striated muscle fibers, around arterial blood vessels, and in the muscularis mucosae. A majority of motor endplates (as demonstrated by acetylcholinesterase histochemistry or calcitonin gene-related peptide immunocytochemistry) were associated with fine varicose NADPH-diaphorase-positive nerve fibers. Analysis of brainstem nuclei, sensory vagal, spinal, and sympathetic ganglia in normal and neonatally capsaicin-treated rats, and comparison with anterogradely labeled vagal branchiomotor, preganglionic and sensory fibers led to the conclusion that NADPH-diaphorase-positive fibers on motor endplates originate in esophageal myenteric neurons. No association of NADPH-diaphorasepositive nerve fibers with motor endplates was found in other organs containing striated muscle. These results suggest extensive, presumably nitrergic, co-innervation of esophageal striated muscle fibers by enteric neurons. Thus, control of peristalsis in the esophagus of the rat may be more complex than hitherto assumed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00354780
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  • 28
    Digitale Medien
    Digitale Medien
    Ontogeny of alpha-crystallin subunits in the lens of human and rat embryos (1994)
    Springer
    Cell & tissue research 276 (1994), S. 151-154 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Eye ; Lens ; Development, ontogenetic ; αA-crystallin ; αB-crystallin ; Immunohistochemistry ; Human ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The distribution of αA- and αB-crystallin in the developing lens of human (Carnegie stages 13 to 23) and rat embryos (embryonic days E11 to 18) was examined immunohistochemically. In a human embryo at stage 13, the lens placode was already immunoreactive to αB-crystallin, but not to αA-crystallin. At stage 15, the lens vesicle was intensely immunoreactive both to αA- and αB-crystallin. From stages 16 to 23, the lens epithelial cells and fiber cells were immunoreactive to αA- and αB-crystallin. In rat embryos, αA-crystallin appeared in the lens pit at E12, and αB-crystallin appeared in the elongating lens fiber cells at E14. From E15 to E18, the lens epithelial cells and fiber cells were immunoreactive to αA-crystallin. The lens fiber cells were also immunoreactive to αB-crystallin, but the epithelial cells were not. These findings suggest that αB-crystallin appears earlier than αA-crystallin in the human lens, but at a later period than αA-crystallin in the rat lens. αB-Crystallin was not detected in the epithelial cells of the rat lens, but was perisistently present in the epithelial cells of the human lens.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00354794
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  • 29
    Digitale Medien
    Digitale Medien
    Nitric oxide synthase in the rat carotid body and carotid sinus (1994)
    Springer
    Cell & tissue research 276 (1994), S. 559-564 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Baroreceptor ; Carotid body ; Carotid sinus ; Chemoreceptor ; Nitric oxide ; Nitric oxide synthase ; NADPH-diaphorase histochemistry ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The participation of nitric oxide synthase (NOS) in the innervation of the rat carotid body and carotid sinus was investigated by means of NADPH-diaphorase histochemistry and NOS immunohistochemistry using antisera raised against purified neuronal NOS and a synthetic tridecapeptide. NOS was detected in 23% of neurons at the periphery of the carotid bodies. Some negative neurons were surrounded by NOS-positive terminals. NOS-containing varicose nerve fibres innervated the arterial vascular bed and, to a lesser extent, the islands of glomus cells. These fibres persisted after transection of the carotid sinus nerve and are probably derived from intrinsic neurons. Large NOS-positive axonal swellings in the wall of the carotid sinus were absent after transection of the sinus nerve, indicating their sensory origin. The results suggest a neuronal nitrergic control of blood flow, neuronal activity and chemoreception in the carotid body, and an intrinsic role of NO in the process of arterial baroreception.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00343953
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  • 30
    Digitale Medien
    Digitale Medien
    Surface area of apical and basolateral plasmalemma of epithelial cells of the ductuli efferentes testis of the rat (1994)
    Springer
    Cell & tissue research 276 (1994), S. 581-586 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Ductuli efferentes ; Stereology ; Fluid transport ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Serial sectioning was used to determine the occurrence of ciliated cells, and a morphological technique was used to estimate the relative and absolute surface areas of apical and basolateral membrane of the epithelial cells lining the ductuli efferentes of the rat. It was found that the ciliated cells constitute 15% of the epithelial cells and occur as groups of mainly 1–3 cells which are distributed at random in the duct epithelium. For the non-ciliated cells it was estimated that the formation of microvilli by the apical membrane increased the surface area of that border by a factor of 37-fold. The average surface density of the basolateral membrane was 76% the surface density of the apical membrane. However, there was a 3-fold increase in surface density along the apicalbasal axis of the basolateral plasmalemma. In the Discussion, the ductuli efferentes are compared to their homologue, the proximal tubules of the kidney, in the rates of fluid transport and membrane adaptations of their epithelium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00343956
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  • 31
    Digitale Medien
    Digitale Medien
    Growth of rat pancreatic acinar cells quantitated with a monoclonal antibody against the proliferating cell nuclear antigen (1994)
    Springer
    Cell & tissue research 276 (1994), S. 603-609 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Pancreas, exocrine ; Acinar cells ; Proliferation ; Proliferating cell nuclear antigen (PCNA) ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The monoclonal antibody PC10 raised against the proliferating cell nuclear antigen (PCNA) was used to study acinar cell replication in the pancreas of rats under different functional conditions. In Western blots, the antibody recognized a single band of 37 kDa in pancreatic homogenates indicating its specificity in this particular species and organ. Three conditions of growth were chosen for immunohistochemical analysis: pancreatic preand postnatal development, pancreatic regeneration after injury, and cholecystokinin-stimulated acinar cell proliferation. The time course of acinar cell replication under each condition was the same as that obtained after tritiated thymidine incorporation with subsequent autoradiography, indicating that the percentage of PCNA-positive cells reflects the pool of cycling cells in the models investigated. However, the absolute number of PCNA-positive cells was two to ten times higher than comparable labeling indices from 3H-thymidine autoradiography. This finding might reflect the half life of PCNA, which exceeds the duration of the S-phase. Thus, PCNA-positive cells not only represent S-phase cells, but also cells that have recently completed the cell cycle.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00343959
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  • 32
    Digitale Medien
    Digitale Medien
    Immunohistochemical analysis of EGF in epiphyseal growth plate from normal, hypophysectomized, and growth hormone-treated hypophysectomized rats (1994)
    Springer
    Cell & tissue research 278 (1994), S. 279-282 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: EGF ; Cartilage ; Growth plate ; Hypophysectomy ; Growth hormone ; Immunohistochemistry ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. Epiphyseal growth plate cartilages from the proximal tibia of normal, hypophysectomized, and growth hormone (GH)-treated hypophysectomized rats were subjected to immunohistochemistry for detection of epidermal growth factor (EGF). In the normal growth plate, EGF was distributed mainly in the proliferative zone. Hypophysectomy resulted in considerable atrophy of the chondrocytes and the cartilage matrix (a decreased number of mature-type chondrocytes and a decreased ratio of proliferating to hypertrophic chondrocytes) and a significant diminution of EGF immunoreactivity. Treatment with GH reversed these effects of hypophysectomy, causing an increased thickness of the growth plate and EGF-reactive sites in all chondrocyte layers. The most intense immunostaining for EGF, however, was frequently seen in the nuclei of chondrocytes with flattened appearance. It appears that EGF could be incorporated or synthesized in chondrocytes having marked mitogenic activity. The present results, taken with previous data on EGF involvement in growth of cartilaginous tissue in vivo and in vitro, strongly suggest that EGF-immunoreactive chondrocytes are involved in cartilage proliferation and growth under the specific influence of GH.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00414171
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  • 33
    Digitale Medien
    Digitale Medien
    Cytoskeletal features in longitudinal and circular smooth muscles during development of the rat portal vein (1994)
    Springer
    Cell & tissue research 279 (1994), S. 199-208 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Hepatic portal vein ; Smooth muscle cell differentiation ; α-Smooth muscle actin ; Desmin ; Thick ; thin filaments ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. Immunohistochemistry of α-smooth muscle actin and desmin, two markers of smooth muscle cell differentiation, and electron-microscopic observation of thick filaments of myosin were performed on the media of the developing rat hepatic portal vein to gain insights into the chronology of differentiation of its longitudinal and circular smooth muscles. In accordance with the ultrastructural distribution of thin filaments, staining of α-smooth muscle actin is lightly positive in the myoblasts at postnatal day 1 and then extends in probably all muscle cells of the developing vessel. Desmin, which appears later than α-smooth muscle actin in the two muscles, is distributed throughout the longitudinal layer at day 8, whereas the first arrangements of thick filaments are detectable in most longitudinal muscle cells; at this stage, desmin and thick filaments are absent from the poorly differentiated circular muscle cells. The longitudinal muscle cells differentiate in a strikingly synchronized way from day 8 onwards, conferring a homogeneous structure to the developing and mature longitudinal layer. Several desmin-positive cells and a heterogeneous distribution of thick filaments occur in the circular muscle at day 14; the subsequent extension of these filaments in this layer results in a persisting heterogeneous distribution in the young 7-week-old adult. Many features of the mature smooth muscle cells are established within the third week in the longitudinal muscle, approximately one week before those of the circular layer. These results are consistent with the function of the longitudinal muscle as a spontaneously contractile smooth muscle unit, and emphasize the need for its fast maturation to fulfil its major role in the control of portal blood flow.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410050274
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  • 34
    Digitale Medien
    Digitale Medien
    Immunohistochemical demonstration of calbindin-containing nerve endings in the rat esophagus (1994)
    Springer
    Cell & tissue research 278 (1994), S. 57-64 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Calbindin ; Sensory nerve endings ; Esophagus ; Immunohistochemistry ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Immunoreactivity for calbindin was found in nerve endings with irregular laminar shapes in the rat esophagus. In the myenteric ganglia, laminar endings of a range of sizes formed a complex network and appeared to lie at the surface of the ganglion. The myenteric ganglia that contained nerve endings were most abundant in the upper portion of the eosphagus, their number decreasing orally to anally. Calbindin-immunoreactive nerve cell bodies were scattered throughout the esophagus. Laminar terminals were found in the connective tissue of the lamina propria immediately beneath the epithelium and in the muscularis mucosae. Occasional nerve branches formed a network of aborizing endings that surrounded part of the submucosal arterioles. Immunoreactive nerve endings in the mucosa and submucosa were present only in the upper part of the cervical esophagus. Unilateral vagotomy caused a remarkable decrease in the number of the myenteric ganglia containing the calbindin-immunoreactive laminar endings after 15 days or survival; in some of ganglia, the laminar structures disappeared and nerve endings showing weak immunoreactivity had an indistinct appearance, so that the outline of the ganglia became obscure. In operated rats at 24 days, the number of innervated ganglia was about half that in normal rats. However, there was no change in the morphology and the occurrence of the immunoreactive laminar structures in the mucosa and submucosa after denervation. The results show that many of the laminar endings that are immunoreactive for calbindin in the myenteric ganglia are derived from the vagus nerve. Thus, the calbindin-immunoreactive nerve endings with laminar expansions that are found in the rat eosphageal wall could be sensory receptors.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00305778
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  • 35
    Digitale Medien
    Digitale Medien
    Rostro-caudal patterning of receptor-expressing olfactory neurones in the rat nasal cavity (1994)
    Springer
    Cell & tissue research 278 (1994), S. 11-20 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Olfactory epithelium ; Sensory cells ; Hybridization ; in situ ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. The rostro-caudal extent of odorant receptor expression zones in the rat olfactory epithelium was analysed by means of in situ hybridization. Three broad non-overlapping zones were identified that extended along almost the entire anterior-posterior axis; each zone was composed of several separate bands running anterior to posterior throughout the olfactory epithelium. Superimposed onto these broad zones was the expression area of a particular receptor subtype (OR37); it was restricted to a small region of the epithelial sheet with a high density of reactive neurones in the centre and declining numbers towards the periphery of the region. A quantitative evaluation of the reactive cells revealed that, despite their different distribution patterns, all receptor subtypes were expressed in an equal number of neurones.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00305773
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  • 36
    Digitale Medien
    Digitale Medien
    Comparison of actin-filament bundles in myoid cells and Sertoli cells of the rat, golden hamster and mouse (1994)
    Springer
    Cell & tissue research 275 (1994), S. 395-398 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Seminiferous tubules ; Myoid cells ; Sertoli cells ; Actin filaments ; Morphometry ; Confocal laser microscopy ; Rat (Wistar) ; Golden hamster ; Mouse (ICR)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Testes of adult rats, golden hamsters and mice were fixed with paraformaldehyde. Seminiferous tubules were then isolated by collagenase dissociation, stained with fluorescent phallotoxin, and viewed in a confocal laser microscope to observe actin filaments. Bundles of actin filaments in the myoid cells, especially in the rat, were arranged at right angles to each other in relation to the longitudinal axis of the tubule. In the hamster, circumferentially directed bundles were more frequent than longitudinally directed bundles. The actin bundles in the mouse were thinner than those in the rat and hamster, and their lattice network was less prominent. Nuclei of the myoid cells were elliptical and their short diameters were parallel to the long axis of the seminiferous tubules in the animals examined. Areas of myoid cells and of basal junctional portions of Sertoli cells were measured and compared in all animals studied. There were significant differences in the areas among the three species. The golden hamster showed the largest value for myoid-cell area, and the mean value for Sertoli-cell area was highest in the mouse.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319439
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  • 37
    Digitale Medien
    Digitale Medien
    Immunocytochemical localization of a growth-associated protein (GAP-43) in rat adrenal gland (1994)
    Springer
    Cell & tissue research 275 (1994), S. 555-566 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Adrenal ; Autonomic nervous system ; Schwann cells ; Tyrosine hydroxylase ; GAP-43 ; Electron microscopy ; Immunohistochemistry ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract We have localized at light and electron-microscopic level the growth-associated protein GAP-43 in adrenal gland using single and double labelling immunocytochemistry. Clusters of GAP-43-immunofluorescent chromaffin cells and many immunofluorescent fibres were observed in the medulla. GAP-43-immunoreactive fibres also formed a plexus under the capsule, crossed the cortex and ramified in the zona reticulata. Double labelled sections showed the coexpression of GAP-43 with a subpopulation of tyrosine hydroxylase-and of dopamine-β-hydroxylase-immunoreactive chromaffin cells. Dual colour immunofluorescence for GAP-43 and calcitonin gene-related peptide (CGRP) revealed that some of the GAP-43-immunoreactive fibres also express CGRP. Pre-embedding electron microscopy showed GAP-43 immunoreactivity associated with the plasma membranes and cytoplasm of noradrenaline-producing chromaffin cells, and with processes of nonmyelin-forming Schwann cells. Immunoreactive unmyelinated axons and terminals were also observed. The immunostained terminals made symmetrical synaptic contacts with chromaffin cells. Immunoreactive unmyelinated fibres and small terminals were present in the cortex. Our results show that GAP-43 is expressed in noradrenergic chromaffin cells and in various types of nerve fibres that innervate the adrenal. Likely origins for these fibres include preganglionic sympathetic fibres which innervate chromaffin cells, postganglionic sympathetic fibres in the cortex, and CGRP containing sensory fibres.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318824
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  • 38
    Digitale Medien
    Digitale Medien
    Effects of gonadotropin-releasing hormone (GnRH) on the cytodifferentiation of gonadotropes in rat adenohypophysial primordia in organ culture (1994)
    Springer
    Cell & tissue research 276 (1994), S. 35-43 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Organ culture ; Pituitary primordium ; Gonadotropes ; LH ; GnRH ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The effects of gonadotropin-releasing hormone (GnRH) on the development of gonadotropes were investigated by the use of organ culture and by means of immunocytochemistry and radioimmunoassay. Pituitary primordia from rat fetuses were cultured in a medium with or without 10-9 M GnRH during the first 24 h of culture. The ratio of the number of immunoreactive LH cells to the total number of cells in the explants derived from 13.5-day fetuses was increased by the GnRH treatment after 6 or 8 days of culture, while the total number of cells was not altered. LH released into the medium and LH content of explants were not affected by the GnRH treatment. Subsequent treatment with 10-9 M GnRH for 4 h after 7 days of culture resulted in a marked release of LH, accompanying a significant decline in LH content, in both explants exposed or unexposed to the first GnRH treatment. However, the former explants contained a lower amount of LH than the latter explants. The present results indicate that pituitary primordia at 13.5 days of gestation are capable to respond to GnRH, and that GnRH is effective in stimulating the responsiveness of gonadotropes to GnRH during early pituitary cytodifferentiation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00354782
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  • 39
    Digitale Medien
    Digitale Medien
    Immunolocalization of albumin and transferrin in germ cells and Sertoli cells during rat gonadal morphogenesis and postnatal development of the testis (1994)
    Springer
    Cell & tissue research 276 (1994), S. 347-351 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Albumin ; Transferrin ; Germ cells ; Sertoli cells ; Testis ; Immunocytochemistry ; Ontogenesis ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The localization of albumin and transferrin was examined immunohistochemically in germ cells and Sertoli cells during rat gonadal morphogenesis and postnatal development of the testis. These proteins appeared as early as the 13th day of gestation in migrating primordial germ cells before Sertoli cell differentiation. In the fetal testis, strong immunoreactivity was only detected in the gonocytes. In the prepubertal testis, spermatogonia, primary spermatocytes, and some Sertoli cells accumulate albumin and transferrin. At puberty, different patterns of immunostaining of the germ cells were observed at the various stages of the cycle of the seminiferous epithelium. Diplotene spermatocytes at stage XIII, spermatocytes in division at stage XIV, and round spermatids at stages IV–VIII showed maximal staining. Labeling was evident in the cytoplasm of adult Sertoli cells. Albumin and transferrin staining patterns paralleled each other during ontogenesis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00306119
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  • 40
    Digitale Medien
    Digitale Medien
    Immunolocalization of glucose transporter GLUT1 in the rat placental barrier: possible role of GLUT1 and the gap junction in the transport of glucose across the placental barrier (1994)
    Springer
    Cell & tissue research 276 (1994), S. 411-418 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Placenta ; Glucose transporter GLUT1 ; Syncytiotrophoblast ; Placental barrier ; Gap junction ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract GLUT1 is an isoform of facilitated-diffusion glucose transporters and has been shown to be abundant in cells of blood-tissue barriers. Using antibodies against GLUT1, we investigated the immunohistochemical localization of GLUT1 in the rat placenta. Rat placenta is of the hemotrichorial type. Three cell layers (from the maternal blood side inward) cytotrophoblast and syncytiotrophoblasts I and II, lie between the maternal and fetal bloodstreams. GLUT1 was abundant along the invaginating plasma membrane facing the cytotrophoblast and the syncytiotrophoblast I. Also, the infolded basal plasma membrane of the syncytiotrophoblast II was rich in GLUT1. Apposing plasma membranes of syncytiotrophoblasts I and II, however, had only a small amount of GLUT1. Numerous gap junctions were seen between syncytiotrophoblasts I and II. Taking into account the localization of GLUT1 and the gap junctions, we suggest a possible major transport route of glucose across the placental barrier, as follows: glucose in the maternal blood passes freely through pores of the cytotrophoblast. Glucose is then transported into the cytoplasm of the syncytiotrophoblast I via GLUT1. Glucose enters the syncytiotrophoblast II throught the gap junctions. Finally glucose leaves the syncytiotrophoblast II via GLUT1 and enters the fetal blood through pores of the endothelial cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00343939
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  • 41
    Digitale Medien
    Digitale Medien
    Olfactory neurones expressing distinct odorant receptor subtypes are spatially segregated in the nasal neuroepithelium (1994)
    Springer
    Cell & tissue research 276 (1994), S. 429-438 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Olfactory epithelium ; Sensory cells ; Hybridization, in situ ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract In situ hybridization techniques have been employed to explore the olfactory epithelium of the rat for the distribution of odorant receptor gene transcripts. We demonstrate that olfactory neurone subpopulations expressing distinct receptor subtypes are spatially segregated within the olfactory epithelium. A compartmentalization of the neuroepithelium into distinct expression zone is apparent, cells expressing a specific receptor are randomly distributed within a given zone. Structurally related receptor subtypes share a common distribution pattern.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00343941
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  • 42
    Digitale Medien
    Digitale Medien
    Rostro-caudal patterning of receptor-expressing olfactory neurones in the rat nasal cavity (1994)
    Springer
    Cell & tissue research 278 (1994), S. 11-20 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Olfactory epithelium ; Sensory cells ; Hybridization, in situ ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The rostro-caudal extent of odorant receptor expression zones in the rat olfactory epithelium was analysed by means of in situ hybridization. Three broad non-overlapping zones were identified that extended along almost the entire anterior-posterior axis; each zone was composed of several separate bands running anterior to posterior throughout the olfactory epithelium. Superimposed onto these broad zones was the expression area of a particular receptor subtype (OR37); it was restricted to a small region of the epithelial sheet with a high density of reactive neurones in the centre and declining numbers towards the periphery of the region. A quantitative evaluation of the reactive cells revealed that, despite their diferent distribution patterns, all receptor subtypes were expressed in an equal number of neurones.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00305773
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  • 43
    Digitale Medien
    Digitale Medien
    Immunocytochemical localization of aromatase-containing neurons in the rat brain during pre- and postnatal development (1994)
    Springer
    Cell & tissue research 278 (1994), S. 29-39 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Aromatase ; Brain ; Development, ontogenetic ; Immunocytochemistry ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract the present immunohistochemical study demonstrates the ontogenetic appearance of aromatase-immunoreactive neurons in several discrete regions of the hypothalamus and limbic system in the rat brain, using a purified antibody against human placental aromatase cytochrome P450. Immunoreactive cells were first detected in the preoptic area on the 13th day of embryonic life (E 13), and additionally in the bed nucleus of the stria terminalis on E 15. Labeled cells were also found in the medial amygdaloid nucleus and the ventromedial nucleus on E 16, and some were detected in the arcuate nucleus on E 19. As gestation progressed, the number and the immunoreactivity of these cells gradually increased and peaked within definite periods of perinatal life and there-after declined or disappeared. The immunoreactive cells were also found in the central amygdaloid nucleus and the lateral septal nucleus, and in the ventral pallidum, after the 14th day of postnatal life (P 14) and 30th day (P 30), respectively. The distribution of aromatase-immunoreactive neurons was similar between the sexes, while the immunoreactivity was higher in males than in females after late gestational days. No immunoreaction was detectable in other regions of the telencephalon or midbrain at any time periods studied. The aromatase-immunoreactive neurons in the specific regions may be involved in the sexual differentiation of the brain.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00305775
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  • 44
    Digitale Medien
    Digitale Medien
    Co-localization of nitric oxide synthase and vasoactive intestinal peptide immunoreactivity in neurons of the major pelvic ganglion projecting to the rat rectum and penis (1994)
    Springer
    Cell & tissue research 278 (1994), S. 273-278 
    Details
    ISSN: 1432-0878
    Schlagwort(e): NO synthase ; VIP ; Pelvic ganglion ; Rectum ; Penis ; Fluoro-Gold ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Nitric oxide synthase (NOS)- and vasoactive intestinal peptide (VIP)-immunoreactive neurons projecting to the upper rectum or penis were examined using retrograde tracing combined with immunohistochemistry in the major pelvic ganglion of male rats. Five days after injection of Fluoro-Gold (FG) into the upper rectum or penis, the major pelvic ganglion was treated with colchicine. FG injected into the upper rectum labelled many ganglion neurons in the major pelvic ganglion. Immunohistochemistry showed that 37% of FG-labelled neurons were immunoreactive for NOS and 33% for VIP. After injection of FG into the penis, 41% of FG-labelled neurons were immunoreactive for NOS and 25% for VIP. Serial cryostat sections stained for NOS and VIP, respectively, showed the co-localization of NOS and VIP in the ganglion cells projecting to the rectum and penis. In the major pelvic ganglion of the colchicinetreated animals, about 17% of the ganglion cells were immunoreactive for NOS and 32% were immunoreactive for VIP. These neurons were small in diameter (less than 30 μm). A histogram showing cell sizes in cross-sectional areas of NOS-immunoreactive neurons coincided with that of VIP-immunoreactive neurons. Most of the NOS-and VIP-immunoreactive neurons were less than 600 μm2. These results indicate that small neurons containing both NOS and VIP in the major pelvic ganglion project to the rectum and penis. In the penile erectile tissues and enteric ganglia, NO and VIP may be released from the same axons and may act concomitantly on the target tissue.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00414170
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  • 45
    Digitale Medien
    Digitale Medien
    Immunohistochemical analysis of EGF in epiphyseal growth plate from normal, hypophysectomized, and growth hormone-treated hypophysectomized rats (1994)
    Springer
    Cell & tissue research 278 (1994), S. 279-282 
    Details
    ISSN: 1432-0878
    Schlagwort(e): EGF ; Cartilage ; Growth plate ; Hypophysectomy ; Growth hormone ; Immunohistochemistry ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Epiphyseal growth plate cartilages from the proximal tibia of normal, hypophysectomized, and growth hormone (GH)-treated hypophysectomized rats were subjected to immunohistochemistry for detection of epidermal growth factor (EGF). In the normal growth plate, EGF was distributed mainly in the proliferative zone. Hypophysectomy resulted in considerable atrophy of the chondrocytes and the cartilage matrix (a decreased number of mature-type chondrocytes and a decreased ratio of proliferating to hypertrophic chondrocytes) and a significant diminution of EGF immunoreactivity. Treatment with GH reversed these effects of hypophysectomy, causing an increased thickness of the growth plate and EGF-reactive sites in all chondrocyte layers. The most intense immunostaining for EGF, however, was frequently seen in the nuclei of chondrocytes with flattened appearance. It appears that EGF could be incorporated or synthesized in chondrocytes having marked mitogenic activity. The present results, taken with previous data on EGF involvement in growth of cartilaginous tissue in vivo and in vitro, strongly suggest that EGF-immunoreactive chondrocytes are involved in cartilage proliferation and growth under the specific influence of GH.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00414171
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  • 46
    Digitale Medien
    Digitale Medien
    Three-dimensional architecture of the tubular endocytic apparatus and paramembranous networks of the endoplasmic reticulum in the rat visceral yolk-sac endoderm (1994)
    Springer
    Cell & tissue research 278 (1994), S. 353-361 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Yolk sac ; Tubular endosomes ; Smooth endoplasmic reticulum ; Ultrastructure ; Endocytosis ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The three-dimensional architecture of the tubular endocytic apparatus and the endoplasmic reticulum in the rat yolk-sac endoderm was investigated after loading with horseradish peroxidase-conjugated concanavalin A by intrauterine administration. After 30 min, small vesicles (50–150 nm in diameter), small tubules (80–100 nm in diameter) and large vacuoles (0.2–1.0 μm in diameter) in the apical cytoplasm were labeled with the tracer, but lysosomes (1.0–3.5 μm in diameter) in the supranuclear cytoplasm were not labeled until 60 min after loading. Stereo-viewing of the labeled small tubules in thick sections revealed that they were not isolated structures but formed three-dimensional anastomosing networks, which were also confirmed by scanning electron microscopy after maceration with diluted osmium tetroxide. Their earlier labeling with the endocytic tracer, localization in the apical cytoplasm and three-dimensional network formation indicated that the labeled small tubules represented tubular endosomes (tubular endocytic apparatus). These well-developed membranous networks provided by the tubular endosomes are suggested to facilitate the receptor-mediated endocytosis and transcytosis of the maternal immunoglobulin in the rat yolk-sac endoderm. Scanning electron microscopy further revealed lace-like networks of the smooth endoplasmic reticulum near the lateral plasma membrane. Their possible involvement in transport of small molecules or electrolytes is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00414178
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  • 47
    Digitale Medien
    Digitale Medien
    Evaluation of various methods for the detection of barley yellow dwarf virus by the tissue-blot immunoassay and its use for virus detection in cereals inoculated at different growth stages (1994)
    Springer
    European journal of plant pathology 100 (1994), S. 71-80 
    Details
    ISSN: 1573-8469
    Schlagwort(e): wheat ; Triticum aestivum ; oat ; Avena sativa ; barley ; Hordeum vulgare ; serology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Various modifications of the tissue-blot immunoassay (TBIA) for the detection of barley yellow dwarf virus (BYDV, luteovirus) were compared. Similar results were obtained by using three different labelled molecules; goat anti-rabbit antibodies conjugated to alkaline phosphatase, protein A conjugated with alkaline phosphatase and goat anti-rabbit antibodies conjugated with colloidal gold. Blocking the nitrocellulose membrane with polyvinyl alcohol for 1 min was effective and allowed the procedure to be shortened by one hour. TBIA was sensitive enough to detect BYDV in old dry tissue wich had been soaked in water for 1 h. BYDV was monitored by TBIA in wheat, oat and barley after inoculation at heading, flowering and grain filling growth stages. The later the inoculation date, the greater the chance of detecting the virus in stem bases rather than in the upper part of the stem. The later the inoculation the less virus moved, from the inoculated tiller to other tillers of the same plant.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01871967
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  • 48
    Digitale Medien
    Digitale Medien
    Growth and elemental content of several sagebrush-steppe species in unburned and post-wildfire soil and plant effects on soil attributes (1994)
    Springer
    Plant and soil 164 (1994), S. 35-41 
    Details
    ISSN: 1573-5036
    Schlagwort(e): nitrogen ; phosphorus ; revegetation ; silica ; succession ; shrubland
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Fire is the principal means of stand renewal in big sagebrush-steppe communities of western North America. Plant growth following fire may be influenced by heat-induced changes in the nutrient status of the soil. Moreover, post-wildfire pioneer plant species may alter soil properties, and thereby, impact subsequent plant recruitment. Our study compared the growth and elemental content of big sagebrush (Artemisia tridentata), squirreltail (Elymus elymoides), cheatgrass (Bromus tectorum), and Indian ricegrass (Achnatherum hymenoides), grown under greenhouse conditions in post-wildfire and similar unburned soil. We also examined soil attributes following plant growth. Cheatgrass and squirreltail, grown in post-wildfire soil, had significantly (p≤0.05) greater aboveground mass than plants grown in unburned soil. As compared with unburned soil, post-wildfire soil engendered the following significant (p≤0.05) differences in leaf elemental content: 1) big sagebrush had higher levels of P and lower levels of Mn; 2) squirreltail accumulated more P and N; and 3) all grass species had higher SiO2 content. Following harvest of plants, post-wildfire soil generally contained significantly (p≤0.05) more KCl-extractable ortho-P, NH inf4 + , and SO 4 − , than unburned soil. Plant growth in both burned and unburned soils fostered a significant (p≤0.05) increase in the bicarbonate-extractable pool of P as compared with unplanted controls. Soil Kjeldahl-N was significantly (p≤0.05) greater after plant growth in burned treatments as compared with the control. This study demonstrates that post-wildfire soil can have a stimulatory effect on plant growth for some species. Squirreltail deserves consideration as a post-wildfire revegetation species. Furthermore, pioneer plant growth following wildfires can attenuate soil properties and therefore influence plant succession.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00010108
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  • 49
    Digitale Medien
    Digitale Medien
    Extractable sulphate and organic sulphur in soils and their availability to plants (1994)
    Springer
    Plant and soil 164 (1994), S. 243-250 
    Details
    ISSN: 1573-5036
    Schlagwort(e): organic sulphur ; soil testing ; sulphate ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Ten soils collected from the major arable areas in Britain were used to assess the availability of soil sulphur (S) to spring wheat in a pot experiment. Soils were extracted with various reagents and the extractable inorganic SO4-S and total soluble S(SO4-S plus a fraction of organic S) were determined using ion chromatography (IC) or inductively-coupled plasma atomic emission spectrometry (ICP-AES), respectively. Water, 0.016 M KH2PO4, 0.01 M CaCl2 and 0.01 M Ca(H2PO4)2 extracted similar amounts of SO4-S, as measured by IC, which were consistently smaller than the total extractable S as measured by ICP-AES. The amounts of organic S extracted varied widely between different extractants, with 0.5 M NaHCO3 (pH 8.5) giving the largest amounts and 0.01 M CaCl2 the least. Organic S accounted for approximately 30–60% of total S extracted with 0.016 M KH2PO4 and the organic C:S ratios in this extract varied typically between 50 and 70. The concentrations of this S fraction decreased in all soils without added S after two months growth of spring wheat, indicating a release of organic S through mineralisation. All methods tested except 0.5 M NaHCO3-ICP-AES produced satisfactory results in the regression with plant dry matter response and S uptake in the pot experiment. In general, 0.016 M KH2PO4 appeared to be the best extractant and this extraction followed by ICP-AES determination was considered to be a good method to standardise on.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00010076
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  • 50
    Digitale Medien
    Digitale Medien
    Biofumigation: Isothiocyanates released frombrassica roots inhibit growth of the take-all fungus (1994)
    Springer
    Plant and soil 162 (1994), S. 107-112 
    Details
    ISSN: 1573-5036
    Schlagwort(e): canola ; glucosinolates ; Indian mustard ; take-all ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The presence of root tissue of the brassicas canola and Indian mustard inhibited growth of pure cultures of the fungal pathogen which causes take-all of wheat [Gaeumannomyces graminis (Sacc.) Arx and Oliver var.tritici, abbreviated as Ggt]. Ggt growth was generally inhibited more in the presence of Indian mustard roots than canola roots. Dried irradiated roots were consistently effective in reducing Ggt growth, but growth inhibition by young live roots and macerated roots was not consistent. The inhibitory compound(s) were shown to be volatile because the symmetry of Ggt growth was not affected by the proximity of theBrassica tissue. Volatile breakdown products from maceratedBrassica roots were identified using a gas chromatograph-mass spectrometer. The major compounds found were isothiocyanates (ITCs). Canola roots released mostly methyl ITC and Indian mustard roots released mostly phenylethyl ITC. Low concentrations of these and related compounds inhibited growth of Ggt in pure culture when supplied as the vapour of pure chemicals in concentrations within the range expected during breakdown ofBrassica roots in soil.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01416095
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  • 51
    Digitale Medien
    Digitale Medien
    3Hthymidine incorporation of rhizosphere bacteria influenced by plant N-status (1994)
    Springer
    Plant and soil 162 (1994), S. 113-116 
    Details
    ISSN: 1573-5036
    Schlagwort(e): ammonium ; nitrate ; split-roots ; root exudate ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effect of plant-root N-status on bacterial growth in the rhizosphere was studied with 5-week-old wheat plants grown in soil with low N content obtained by mixing 9:1 gravel:sandy loam. As a consequence of N limitation, significant increase in3Hthymidine (Tdr) incorporation rate occured 3 days after addition of 30 mM ammonium compared to controls without ammonium. Plants were grown with split-roots to separate the effect of soil N from effect of plant root derived organic matter-N on bacterial activity. The increase in nitrate concentration from 10 mM to 30 mM at one part of the root system led to significant increased3HT dr incorporation in the rhizosphere at the other part of root system after 4 days showing that the composition of root exudates became more favourable for bacterial growth when plants were fertilized with the higher level of nitrate.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01416096
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  • 52
    Digitale Medien
    Digitale Medien
    Comparison between a chemical and a biological method to determine the N mineralization potential of temperate-humid region soils (1994)
    Springer
    Plant and soil 162 (1994), S. 147-150 
    Details
    ISSN: 1573-5036
    Schlagwort(e): biological method ; chemical method ; mineralization potential ; nitrogen ; soil incubation ; temperate humid-zone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The potentially mineralizable organic N of 33 different soils was estimated by a chemical test (hot extraction with 2N KCl) and the values compared with those previously obtained by a biological method (aerobic incubation in the laboratory). On average, the organic N solubilized by the chemical procedure was significantly lower than that mineralized by a two weeks aerobic incubation for all the soils as a whole. The same was true for soils developed over acid rocks and over sediments. However, the values obtained for the soils developed over limestone and basic rocks were similar by both methods. The values obtained by both methods were not significantly correlated neither when considering all soils together nor when considering different groups according to soil management or parent material. Significant correlations between both methods were only found when the soils were separated into two groups according to their organic N content: soils with less than 400 mg N 100 g−1 soil and soils with more than 400 mg N 100 g−1 soil. The organic N solubilized by the chemical procedure was significantly correlated with the hexosamine-N content; however, it was not correlated with the factors that control the biological mineralization of the organic N, except with the soluble Al content. Therefore, the chemical extraction did not seem to address the biologically active N pool in a selective way.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01416100
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  • 53
    Digitale Medien
    Digitale Medien
    Growth, biomass allocation and water use efficiency of two wheat cultivars in a mediterranean environment; a pot experiment under field conditions (1994)
    Springer
    Plant and soil 162 (1994), S. 241-247 
    Details
    ISSN: 1573-5036
    Schlagwort(e): biomass allocation ; carbon isotope discrimination ; growth ; water use efficiency ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Plants of two bread wheat cultivars,Triticum aestivum L. ‘Katya Al’ and ‘Mexipak 65’, were grown in pots during the crop season in the field in NW Syria, a region with a Mediterranean climate. The experiment involved two treatments. Control plants were well-watered throughout the experiment (watering to 0.22 g water g−1 dry soil). In the second treatment, water was withheld from the plants until soil water content had decreased to 0.10 g water g−1 dry soil, the level that was maintained thereafter. Water use was measured by weighing the pots, and growth by destructive sampling. Growth of Katya and Mexipak was similar. Mexipak had a lower (though not significant atp〈0.05) plant water use efficiency (WUEp) in both treatments due to higher rates of water loss. On a leaf area basis differences in water use were especially high since Mexipak had a smaller total leaf area. In spite of a smaller investment in photosynthesizing area, Mexipak achieved similar growth as Katya. Carbon isotope discrimination and organic nitrogen concentration (both higher for Mexipak) suggest that Mexipak accomplished higher mean net photosynthetic rates with a higher mean leaf diffusive conductance, higher intercellular carbon dioxide partial pressure, and possibly a greater investment in the photosynthetic apparatus compared to Katya. Differences in carbon isotope discrimination suggest a larger difference in average photosynthetic WUE (net photosynthesis/transpiration) than in plant WUE. This could indicate that loss of carbon in respiration was greater in Katya. Gas exchange measurements on the youngest fully expanded leaves showed only minor differences between the cultivars. It is hypothesized that Mexipak, with a smaller total leaf area, is able to maintain high leaf conductance and photosynthesis for a longer period of time during the day or during the life span of leaves.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01347711
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  • 54
    Digitale Medien
    Digitale Medien
    A simple model for estimating the contribution of nitrogen mineralization to the nitrogen supply of crops from a stabilized pool of soil organic matter and recent organic input (1994)
    Springer
    Plant and soil 162 (1994), S. 259-271 
    Details
    ISSN: 1573-5036
    Schlagwort(e): mineralization rate ; nitrogen ; stabilized organic matter ; crop rotation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A simple model was developed to estimate the contribution of nitrogen (N) mineralization to the N supply of crops. In this model the soil organic matter is divided into active and passive pools. Annual soil mineralization of N is derived from the active pool. The active pool comprises stabilized and labile soil organic N. The stabilized N is built up from accumulated inputs of fresh organic N during a crop rotation but the labile N is a fraction of total N added, which mineralizes faster than the stabilized N. The passive pool is considered to have no participation in the mineralization process. Mineralization rates of labile and stabilized soil organic N from different crop residues decomposing in soil were derived from the literature and were described by the first-order rate equation dN/dt =-K*N, where N is the mineralizable organic N from crop residues andK is a constant. The data were groupedK 1 by short-term (0–1 year) andK 2 by long-term (0–10 years) incubation. Because the range of variation inK 2 was smaller than inK 1 we felt justified in using an average value to derive N mineralization from the stabilized pool. The use of a constant rate ofK 1 was avoided so net N mineralization during the first year after addition is derived directly from the labile N in the crop residues. The model was applied to four Chilean agro-ecosystems, using daily averages of soil temperature and moisture. The N losses by leaching were also calculated. The N mineralization varied between 30 and 130 kg N ha−1 yr−1 depending on organic N inputs. Nitrogen losses by leaching in a poorly structured soil were estimated to be about 10% of total N mineralized. The model could explain the large differences in N- mineralization as measured by the potential N mineralization at the four sites studied. However, when grassland was present in the crop rotation, the model underestimated the results obtained from potential mineralization.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01347713
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  • 55
    Digitale Medien
    Digitale Medien
    The 2,4-D-induced wheat para-nodules are modified lateral roots with structure enhanced by rhizobial inoculation (1994)
    Springer
    Plant and soil 159 (1994), S. 121-129 
    Details
    ISSN: 1573-5036
    Schlagwort(e): 2,4-dichlorophenoxyacetate ; para-nodule ; Rhizobium trifolii ; structure ; Triticum aestivum L. ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Nodular outgrowths (para-nodules or p-nodules) on the roots of wheat (Triticum aestivum L.) cv. Miskle seedlings were induced by treatment with 0.3 and 0.6mg L−1 2,4-dichlorophenoxyacetate (2,4-D). When co-inoculated with Rhizobium trifolii strain ATCC 14480, more p-nodules were formed at these levels and p-nodulation occured at 0.1 mg L−1 indicating that inoculation enhances 2,4-D-induced p-nodulation. Similar to lateral roots, the p-nodules arose from the pericycle opposite the phloem tissues and were free from the cortical cells of the parental root at all stages of development. Structurally, the p-nodules exhibited tissue differentiation. They possessed a highly organized central vascular cylinder connected to that of the parent root, an endodermis, a cap, and an apical and lateral meristems. P-nodules formed by 2,4-D treatment alone were irregularly lobed due to uncoordinated activity of the apical meristem, while those in the combined 2,4-D and inoculation treatment were more globose. The results of the present study indicate that the 2,4-D-induced wheat p-nodules are modified lateral roots, the structure of which is enhanced by rhizobial inoculation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00009294
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  • 56
    Digitale Medien
    Digitale Medien
    Root architectural responses of Betula lenta to spatially heterogeneous ammonium and nitrate (1994)
    Springer
    Plant and soil 158 (1994), S. 129-134 
    Details
    ISSN: 1573-5036
    Schlagwort(e): Betula lenta L. ; black birch ; nitrogen ; root architecture ; soil heterogeneity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Inorganic soil nitrogen is often heterogeneously distributed, both spatially and in form (ammonium versus nitrate). Here we present information on the architecture of black birch (Betula lenta L.) root systems exposed to homogeneous and heterogeneous nitrogen environments. The major effects on root architecture were at the whole root system level in response to heterogeneity of nitrogen form rather than the effect of local of local nitrate or ammonium supply on local root growth. In the heterogeneous treatment, plant root systems had greater link lengths and more simple branching patterns. Root architectural responses to heterogeneous nitrogen, independent of localized responses to patches, suggest that in a seedling of B. lenta whole plant integration of its environment may override local control of root growth.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00007925
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  • 57
    Digitale Medien
    Digitale Medien
    Root response to CO2 enrichment and nitrogen supply in loblolly pine (1994)
    Springer
    Plant and soil 165 (1994), S. 21-32 
    Details
    ISSN: 1573-5036
    Schlagwort(e): allocation ; CO2 ; image analysis ; loblolly pine ; nitrogen ; root morphology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract This paper examines how elevated CO2 and nitrogen (N) supply affect plant characteristics of loblolly pine (Pinus taeda L.) with an emphasis on root morphology. Seedlings were grown in greenhouses from seeds during one growing season at two atmospheric CO2 concentrations (375 and 710 μL L-1) and two N levels (High and Low). Root morphological characteristics were determined using a scanner and an image analysis program on a Macintosh computer. In the high N treatment, elevated CO2 increased total plant dry weight by 80% and did not modify root to shoot (R/S) dry weight ratio, and leaf and plant N concentration at the end of the growing season. In the low N treatment, elevated CO2 increased total dry weight by 60%. Plant and leaf N concentration declined and R/S ratio tended to increase. Nitrogen uptake rate on both a root length and a root dry weight basis was greater at elevated CO2 in the high N treatment and lower in the low N treatment. We argue that N stress resulting from short exposures to nutrients might help explain the lower N concentrations observed at high CO2 in other experiments; Nitrogen and CO2 levels modified root morphology. High N increased the number of secondary lateral roots per length of first order lateral root and high CO2 increased the length of secondary lateral roots per length of first order lateral root. Number and length of first order lateral roots were not modified by either treatment. Specific root length of main axis, and to a lower degree, of first order laterals, declined at high CO2, especially at high N. Basal stem diameter and first order root diameters increased at high CO2, especially at high N. Elevated CO2 increased the proportion of upper lateral roots within the root system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00009959
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  • 58
    Digitale Medien
    Digitale Medien
    Enhanced root system C-sink activity, water relations and aspects of nutrient acquisition in mycotrophic Bouteloua gracilis subjected to CO2 enrichment (1994)
    Springer
    Plant and soil 165 (1994), S. 139-146 
    Details
    ISSN: 1573-5036
    Schlagwort(e): blue grama ; Bouteloua gracilis ; C4 grass ; CO2 enrichment ; mycorrhizae ; nitrogen ; phosphorus ; VAM ; water relations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In order to better elucidate fixed-C partitioning, nutrient acquisition and water relations of prairie grasses under elevated [CO2], we grew the C4 grass Bouteloua gracilis (H.B.K.) lag ex Steud. from seed in soil-packed, column-lysimeters in two growth chambers maintained at current ambient [CO2] (350 μL L−1) and twice enriched [CO2] (700 μL L−1). Once established, plants were deficit irrigated; growth chamber conditions were maintained at day/night temperatures of 25/16°C, relative humidities of 35%/90% and a 14-hour photoperiod to simulate summer conditions on the shortgrass steppe in eastern Colorado. After 11 weeks of growth, plants grown under CO2 enrichment had produced 35% and 65% greater total and root biomass, respectively, and had twice the level of vesicular-arbuscular mycorrhizal (VAM) infection (19.8% versus 10.8%) as plants grown under current ambient [CO2]. The CO2-enriched plants also exhibited greater leaf water potentials and higher plant water use efficiencies. Plant N uptake was reduced by CO2 enrichment, while P uptake appeared little influenced by CO2 regime. Under the conditions of the experiment, CO2 enrichment increased root biomass and VAM infection via stimulated growth and adjustments in C partitioning below-ground.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00009970
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  • 59
    Digitale Medien
    Digitale Medien
    The completion of cell proliferation and growth in wheat radicle (1994)
    Springer
    Plant and soil 167 (1994), S. 43-49 
    Details
    ISSN: 1573-5036
    Schlagwort(e): DNA contents ; DNA synthesis ; growth ; proliferation ; radicle ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The pattern of proliferation and growth of cortical and central metaxylem cells in a radicle and the transitional zone of a wheat embryo was studied during the final stages of embryogenesis. Cell divisions finished nearer the root tip in the central metaxylem than was the case in the cortex. After divisions ceased the cells of both tissues maintained the ability to synthesize DNA and the cells began DNA endoreduplication. The maximal levels of endoreduplication were 4C and 8C in cortical and central metaxylem cells, respectively. As a result of nonsimultaneous cessation of divisions, the metaxylem cells were two or three times longer than cortical cells. The proportion of cells with the maximal DNA content was smaller in the transitional zone than in the radicle. During the final embryonal stages cell growth rate was decreased. It was established that the transition of cells to DNA synthesis was inhibited in all sites of the radicle during the completion of embryogenesis. The cell growth was topped in proximal sites of the radicle. In the division zone the cells which had already begun DNA synthesis were able to complete it and divided. Cell growth stopped simultaneously with completion of proliferation in this zone.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01587596
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  • 60
    Digitale Medien
    Digitale Medien
    Genetic basis of grain filling rate in wheat (Triticum aestivum L. emend. Thell.) (1994)
    Springer
    Euphytica 76 (1994), S. 33-44 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; genetic basis ; grain filling rate ; genetic effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Grain filling rate in wheat (Triticum aestivum L. emend. Thell.) positively influences grain yield under a wide range of conditions. The effective utilization of this trait in breeding depends on an understanding of its genetic control. A study was, therefore, conducted to determine the genetic basis of grain filling rate in six crosses of wheat. Higher order genic interactions and/or linkage were important in the genetic regulation of grain filling rate (GFR) in the majority of crosses. Additive ([d]) and dominance ([h]) gene effects were important in the control of GFR in main ears (ME) and whole plant ears (WPE). Additive and additive × additive epistatic effects were the most important in the genetic control of GFR in last ears (LE). Location effects on genetic effects for GFR were significant (P 〈 0.05) in all ear types of some crosses except in ME. Genotype × environment interaction effects were important (P 〈 0.001) in LE and WPE. It was concluded that the inheritance of GFR is complex and is dependent on ear type. Breeding procedures that facilitate the exploitation of non-additive and additive gene effects were recommended for the genetic improvement of grain filling rate of wheat.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00024018
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  • 61
    Digitale Medien
    Digitale Medien
    Analysis of disease resistance and quality characters of F1 hybrids of crosses between wheat (Triticum aestivum) and spelt (Triticum spelta) (1994)
    Springer
    Euphytica 75 (1994), S. 105-110 
    Details
    ISSN: 1573-5060
    Schlagwort(e): wheat ; spelt ; crosses ; hybrids ; quality ; disease resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary With the objective of creating new combinations of disease resistance and quality, hybrids between wheat and spelt (spelt is well adapted to cool and wet conditions) were produced and the expression of heterosis was analysed. Three winter wheat varieties were crossed reciprocally with two spelt cultivars and the F1 hybrids were tested under artificial inoculation with stripe rust, powdery mildew and leaf rust. Disease susceptibility and quality characters (protein content, Zeleny value, grain hardness) were assessed in two year field trials. For stripe rust the F1 hybrids were resistant if one of the wheat parents was resistant. Combinations with the susceptible wheat cultivar ‘Arina’ were all susceptible irrespective of using a resistant spelt partner. Although the infection with powdery mildew was rather low, a similar reaction was obtained with the susceptible wheat variety ‘Bernina’. Leaf rust revealed very specific varietal influences. The two susceptible wheat varieties ‘Bernina’ and ‘Arina’ resulted in susceptible F1 hybrids when combined with a moderately resistant spelt. Only when they were crossed with a resistant spelt cultivar the F1 hybrids were resistant. ‘Forno’, a leaf rust resistant wheat, gave resistant F1 hybrids in all combinations. Without exception the quality characters tested showed a negative heterosis effect resulting in protein levels and Zeleny values close to or below the values of the lower parent. It appears to be possible to produce resistant F1 hybrids, mostly dominated by the resistance level of the wheat partner. The quality of the hybrids is mainly suitable for biscuit and spelt specific products; it needs specific screening for combinations with acceptable breadmaking quality.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00024537
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  • 62
    Digitale Medien
    Digitale Medien
    Mineralization of carbon and nitrogen in acid forest soil treated with fast and slow-release nutrients (1994)
    Springer
    Plant and soil 164 (1994), S. 187-193 
    Details
    ISSN: 1573-5036
    Schlagwort(e): apatite ; biotite ; forest soil ; mineralization ; nitrogen ; nutrient additions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effects of slow (apatite, biotite) and fast-release nutrients (P, K, Mg) on C and N mineralization in acid forest soil were studied. These nutrients were applied alone or together with urea or urea and limestone. The production of CO2 in the soil samples taken one and three growing seasons after the application was lower in the soils treated with the fast-release nutrients than in the untreated soils. Similar reduction of microbial activity was not seen after the apatite and apatite+biotite treatments. In the first growing season, urea and urea+limestone enhanced CO2 production, but after three growing seasons, the opposite was true. Apatite and apatite+biotite added together with urea did not compensate for the decreasing effect of urea on the CO2 production. The addition of fast-release salts increased somewhat the concentration of NH inf4 sup+ in the soil and more NH4 + accumulated during laboratory incubation in the soil samples taken one growing season after the application. The urea addition immediately increased the concentrations of NH4 + and of NO3 − in the soil, but, three growing seasons after application, urea had only a slight increasing effect on mineral N content of the soil. Slow-release nutrients seem to have a more favourable effect than fast-release salts on nutrient turnover in acid forest soil.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00010070
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  • 63
    Digitale Medien
    Digitale Medien
    Nitrogen effects on rhizosphere processes of range grasses from different successional seres (1994)
    Springer
    Plant and soil 161 (1994), S. 241-250 
    Details
    ISSN: 1573-5036
    Schlagwort(e): carbon ; microorganisms ; nitrogen ; plant succession ; range grasses ; rhizosphere
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Nitrogen and rhizosphere microorganism effects on nitrogen and carbon dynamics of Sitanion hystrix (early successional species), Stipa comata and Poa secundu which are (mid-successional species), and Agropyron spicatum (late successional species) were evaluated in a growth chamber study. Rhizosphere inocula resulted in increased nitrogen in both root and shoot tissue, and also of water-extractable carbon in the rhizosphere. Plant species, rhizosphere inocula and nitrogen level showed a three-way significant interaction for total and plant-available nitrogen. Rhizosphere microbe presence resulted in higher plant-available nitrogen in the rhizosphere of S. hystrix and less with A. spicatum, suggesting nitrogen immobilization with the later successional grass. Higher nitrogen resulted in decreased active bacteria in the rhizosphere of all plants tested, and decreased fungal hyphal lengths in the rhizosphere of the later successional P. secunda and A. spicutum. Exudate carbon in the rhizosphere of the late successional species A. spicatum, was more recalcitrant, which also may contribute to nitrogen immobilization. These differential responses of early- and late-successional grasses may be important factors contributing to plant succession.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00046395
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  • 64
    Digitale Medien
    Digitale Medien
    Effects of ammonium sulphate application on the rhizosphere, fine-root and needle chemistry in aPicea abies (L.) Karst. stand (1994)
    Springer
    Plant and soil 162 (1994), S. 71-80 
    Details
    ISSN: 1573-5036
    Schlagwort(e): ammonium sulphate ; fine roots ; needles ; nitrogen ; Norway spruce ; rhizosphere
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Rhizosphere, fine-root and needle chemistry were investigated in a 28 year old Norway spruce stand in SW Sweden. The uptake and allocation pattern of plant nutrients and aluminium in control plots (C) and plots repeatedly treated with ammonium sulphate (NS) were compared. Treatments started in 1988. Current year needles, one-year-old needles and cylindrical core samples of the LFH-layer and the mineral soil layers were sampled in 1988, 1989 and 1990. Compared to the control plots, pH decreased significantly in the rhizosphere soil in the NS plots in 1989 and 1990 while the SO4-S concentration increased significantly. Aluminium concentration in the rhizosphere soil was generally higher in the NS plots in all soil layers, except at 0–10 cm depths, both in 1989 and 1990. Calcium, Mg and K concentrations also increased after treatment with ammonium sulphate. Ammonium ions may have replaced these elements in the soil organic matter. The NS treatment significantly reduced Mg concentrations in fine roots in all layers in 1990. A similar trend was found in the needles. Ca concentrations in fine roots were significantly lower in the NS plots in the LFH layer in 1990 and the same pattern was found in the current needles. The N and S concentrations of both fine roots and needles were significantly higher in the NS plots. It was suggested that NS treatment resulted in displacement of Mg, Ca and K from exchange sites in the LFH layer leading to leaching of these cations to the mineral soil. Further application of ammonium sulphate may damage the fine roots and consequently adversely affect the water and nutrient uptake of root systems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01416091
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  • 65
    Digitale Medien
    Digitale Medien
    Decomposition of tree leaf litters grown under elevated CO2: Effect of litter quality (1994)
    Springer
    Plant and soil 163 (1994), S. 121-130 
    Details
    ISSN: 1573-5036
    Schlagwort(e): decomposition rates ; enriched CO2 ; lignin ; litter respiration ; microcosms ; nitrogen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Ash (Fraxinus excelsior L.), birch (Betula pubescens Ehrh.), sycamore (Acer pseudoplatanus L.) and Sitka spruce (Picea sitchensis (Bong.) Carr.) leaf litters were monitored for decomposition rates and nutrient release in a laboratory microcosm experiment. Litters were derived from solar domes where plants had been exposed to two different CO2 regimes: ambient (350 μL L-1 CO2) and enriched (600 μL L-1 CO2). Elevated CO2 significantly affected some of the major litter quality parameters, with lower N, higher lignin concentrations and higher ratios of C/N and lignin/N for litters derived from enriched CO2. Respiration rates of the deciduous species were significantly decreased for litters grown under elevated CO2, and reductions in mass loss at the end of the experiment were generally observed in litters derived from the 600 ppm CO2 treatment. Nutrient mineralization, dissolved organic carbon, and pH in microcosm leachates did not differ significantly between the two CO2 treatments for any of the species studied. Litter quality parameters were examined for correlations with cumulative respiration and decomposition rates: N concentration, C/N and lignin/N ratios showed the highest correlations, with differences between litter types. The results indicate that higher C storage will occur in soil as a consequence of litter quality changes resulting from higher atmospheric concentrations of CO2.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00033948
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  • 66
    Digitale Medien
    Digitale Medien
    Seedling root response of some Kenyan bread wheat cultivars grown in acid nutrient culture solution containing aluminum (1994)
    Springer
    Plant and soil 158 (1994), S. 141-144 
    Details
    ISSN: 1573-5036
    Schlagwort(e): acid tolerance ; cultivar differences ; root tolerance index ; Triticum aestivum L. ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The objective of this study was to determine whether a series of Kenyan bread wheat cultivars differed in tolerance to aluminum toxicity. Fourteen Kenyan wheat cultivars representing current and former widely grown cultivars of diverse pedigree origin, and two control cultivars, Maringa (Al-tolerant) and Siete Cerros (Al-susceptible), were tested in solution cultures with 0 (control), 148, 593, and 2370 μM Al at pH 4.6. Highly significant (p≤0.01) differences in seedling growth were observed among cultivars for root mass, root length and root tolerance index (RTI). Significant (p≤0.05) cultivar × treatment interactions were observed for root mass and RTI. All characters were negatively affected by increased Al concentration, with root length and root mass being affected the most. RTI is a commonly used index which measures the relative performance of individual cultivars with and without aluminum stress. High levels of tolerance to Al were identified in the Kenyan cultivars by evaluating RTI with this simple nutrient solution technique. Romany and Kenya Nyumbu had RTI values approaching those of the Al tolerant Brazilian cultivar Maringa, a spring wheat standard that has been used for high Al tolerance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00007927
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  • 67
    Digitale Medien
    Digitale Medien
    Nutrient uptake in eastern deciduous tree seedlings (1994)
    Springer
    Plant and soil 160 (1994), S. 193-199 
    Details
    ISSN: 1573-5036
    Schlagwort(e): gaps ; ion uptake ; nitrogen ; nutrient acquisition ; phosphorus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Tree seedlings that colonize large treefall gaps are generally shade-intolerant species with high potential relative growth rates. Nutrient availability may be significantly elevated in disturbance-induced gaps, however, little is known about the role of differences in nutrient uptake capacities of different species in structuring the community response to gap openings in eastern North American deciduous forests. Seven tree species were grown from seed under both a high and a low nutrient regime, and uptake kinetics of phosphate, ammonium, and nitrate were studied. Yellow birch, a species with intermediate shade tolerance and relative growth rate, had the highest maximum rates of uptake of all ions, while tulip tree, a gap-colonizing species with high relative growth rate, had the lowest rate of phosphate uptake and intermediate rates of ammonium and nitrate uptake. Beech and hickory, which have low relative growth rates and are not gap-colonizing species, had intermediate levels of nutrient uptake. There was no evidence that species with the highest maximum uptake rates measured at high supply concentrations had relatively low uptake at low nutrient supply concentrations. Although birch increased phosphate absorption capacity when grown under a low nutrient regime, this pattern did not hold for nitrate or ammonium uptake, and other species showed no change in nutrient uptake capacity according to nutrient growth regime. Clearly, factors other than nutrient absorption capacity, such as nutrient use efficiency or allocation to root vs. shoot biomass, underlie differences in species' capacities to colonize and maintain a high relative growth rate in canopy gaps.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00010145
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  • 68
    Digitale Medien
    Digitale Medien
    Above- and belowground response of Populus grandidentata to elevated atmospheric CO2 and soil N availability (1994)
    Springer
    Plant and soil 165 (1994), S. 45-51 
    Details
    ISSN: 1573-5036
    Schlagwort(e): CO2 ; gas exchange ; nitrogen ; Populus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Soil N availability may play an important role in regulating the long-term responses of plants to rising atmospheric CO2 partial pressure. To further examine the linkage between above- and belowground C and N cycles at elevated CO2, we grew clonally propagated cuttings of Populus grandidentata in the field at ambient and twice ambient CO2 in open bottom root boxes filled with organic matter poor native soil. Nitrogen was added to all root boxes at a rate equivalent to net N mineralization in local dry oak forests. Nitrogen added during August was enriched with 15N to trace the flux of N within the plant-soil system. Above-and belowground growth, CO2 assimilation, and leaf N content were measured non-destructively over 142 d. After final destructive harvest, roots, stems, and leaves were analyzed for total N and 15N. There was no CO2 treatment effect on leaf area, root length, or net assimilation prior to the completion of N addition. Following the N addition, leaf N content increased in both CO2 treatments, but net assimilation showed a sustained increase only in elevated CO2 grown plants. Root relative extension rate was greater at elevated CO2, both before and after the N addition. Although final root biomass was greater at elevated CO2, there was no CO2 effect on plant N uptake or allocation. While low soil N availability severely inhibited CO2 responses, high CO2 grown plants were more responsive to N. This differential behavior must be considered in light of the temporal and spatial heterogeneity of soil resources, particularly N which often limits plant growth in temperate forests.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00009961
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  • 69
    Digitale Medien
    Digitale Medien
    Evaluation of the use of a model rhizodeposition technique to separate root and microbial respiration in soil (1994)
    Springer
    Plant and soil 165 (1994), S. 89-101 
    Details
    ISSN: 1573-5036
    Schlagwort(e): barley ; glucose ; microbial respiration ; pulse-labelling ; rhizodeposition ; root respiration ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A model rhizodeposition technique to estimate the root and microbial components of 14C soil/root respiration in pulse-labelling experiments is described. The method involves the injection of model rhizodeposits, consisting of 14C-labelled glucose, root extract or root cell wall material, into the rooted soil of an unlabelled plant, simultaneously with the pulse-labelling of a separate but similar plant with 14CO2. In a growth chamber experiment with 30 day old wheat and barley the contribution of direct root respiration to 14C soil/root respiration over a 26 day period after labelling was estimated 89–95%. Estimates of direct root respiration in field-grown wheat and barley at different development stages in most cases accounted for at least 75% of 14C soil/root respiration over a 21 day period after labelling. The mineralization rate of injected 14C-glucose was positively correlated with the concentration of glucose-C established in soil. The use of the method in rhizosphere carbon budget estimations is evaluated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00009966
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  • 70
    Digitale Medien
    Digitale Medien
    Soil pCO2, soil respiration, and root activity in CO2-fumigated and nitrogen-fertilized ponderosa pine (1994)
    Springer
    Plant and soil 165 (1994), S. 129-138 
    Details
    ISSN: 1573-5036
    Schlagwort(e): carbon dioxide ; nitrogen ; ponderosa pine ; soil respiration ; soil carbon
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The purpose of this paper is to describe the effects of CO2 and N treatments on soil pCO2, calculated CO2 efflux, root biomass and soil carbon in open-top chambers planted with Pinus ponderosa seedlings. Based upon the literature, it was hypothesized that both elevated CO2 and N would cause increased root biomass which would in turn cause increases in both total soil CO2 efflux and microbial respiration. This hypothesis was only supported in part: both CO2 and N treatments caused significant increases in root biomass, soil pCO2, and calculated CO2 efflux, but there were no differences in soil microbial respiration measured in the laboratory. Both correlative and quantitative comparisons of CO2 efflux rates indicated that microbial respiration contributes little to total soil CO2 efflux in the field. Measurements of soil pCO2 and calculated CO2 efflux provided inexpensive, non-invasive, and relatively sensitive indices of belowground response to CO2 and N treatments.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00009969
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  • 71
    Digitale Medien
    Digitale Medien
    Combined effect of salinity and hypoxia in wheat (Triticum aestivum L.) and wheat-Thinopyrum amphiploids (1994)
    Springer
    Plant and soil 166 (1994), S. 47-54 
    Details
    ISSN: 1573-5036
    Schlagwort(e): amphiploid ; hypoxia ; salinity ; Thinopyrum ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effects of sodium chloride salinity and hypoxia were studied in eight wheat lines and three wheat-Thinopyrum amphiploids in vermiculite-gravel culture. The lines were treated with either 100 or 150 mol m−3 NaCl with and without hypoxia. Saline hypoxic conditions significantly reduced the vegetative growth, water use, grain and straw yields for all wheat varieties except the amphiploids, whereas NaCl or hypoxia alone had less pronounced effects. In addition, saline hypoxic stress reduced K+ concentration and increased significantly the Na+ and Cl− concentrations in cell sap expressed from leaves. There was more Na+ and Cl− accumulation in wheats than the amphiploids in hypoxic conditions at 150 mol m−3 NaCl. Of the wheats, Pato was the most sensitive at all stress levels while aTriticum aestivum cv. Chinese Spring ×Thinopyrum elongatum amphiploid was the most tolerant of the three amphiploids.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02185480
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  • 72
    Digitale Medien
    Digitale Medien
    Effects of growth period, plant age and changes in solution aluminium concentrations on aluminium toxicity in wheat (1994)
    Springer
    Plant and soil 166 (1994), S. 21-30 
    Details
    ISSN: 1573-5036
    Schlagwort(e): aluminium ; growth period ; phosphorus ; plant age ; root length ; root width ; solution culture ; techniques ; Triticum aestivum ; variation ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effects of growth period (time between transplanting and harvesting), plant age at which aluminium (Al) was added to solution, changes in Al concentration, and solution culture techniques (monitoring and adjusting solution Al concentrations thrice weekly or weekly replacement of the solutions) were investigated using a low ionic strength (2.7×10−3 M) solution culture technique. The wheat (Triticum aestivum L.) cultivars Waalt (Al-tolerant) and Warigal (Al-sensitive), or the near isogenic lines bred from these cultivars (RR for the Al-tolerant line and SS for the Al-sensitive line) were grown. In all experiments and treatments, Al additions were required to maintain the nominal concentration. The decline in solution Al concentrations was partially attributed to formation of an Al-hydroxy-phosphate precipitate with an Al:P molar ratio of 2.8 to 4.0. Increasing the growth period from 14 to 28 days increased Al sensitivity in Warigal but not in Waalt. When plants were exposed to Al for the same time, increasing the age of the plants that Al was added to solution decreased sensitivity to Al. Differential Al tolerance between the two lines was evident when solutions were monitored thrice weekly or replaced weekly. However, the Al concentration required to reduce relative yield by a given amount when the solutions were replaced weekly was about twice that when the solutions were monitored. With a constant growth period of 28 days, increasing solution Al concentrations for 3 or more days resulted in decreased yields at harvest. The exact effect depended on the cultivar, plant part (tops or roots), when solution Al concentrations were increased and the duration of the increase. For example, increasing Al concentrations from 5 μM to 20 μM for 10 days reduced yield in the RR line by approximately 50% in the tops and 30% in the roots beyond the effect of 5 M but had no effect in the SS line due to yields already being low at 5 μM. Adding 10 μM Al to solution for 6 days at the beginning of the experiment reduced yield by 25% in the RR line and 50% in the SS line. In contrast, adding 10 μM Al for 6 days in the middle of the growth cycle had no effect on the RR line but reduced yield by approximately 25% in the SS line. These results show that growth period, the age of the plants at which Al is added and the technique used (monitored or weekly replacement) all need to be considered when comparing results from different experiments. These results also show that the Al concentrations in solution need to be regularly monitored in long term experiments.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02185477
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  • 73
    Digitale Medien
    Digitale Medien
    Redox transformations and plant uptake of selenium resulting from root-soil interactions (1994)
    Springer
    Plant and soil 158 (1994), S. 1-12 
    Details
    ISSN: 1573-5036
    Schlagwort(e): acid soils ; ascorbic acid ; barley ; gallic acid ; manganese oxides ; oxidation-reduction ; rhizosphere ; root exudates ; selenium ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Batch studies were conducted with Mn oxides (birnessite-hausmannite mixture, BHM) and samples of four soil series from the Mid-Atlantic region of the USA to determine effects of reducing organic acids, similar to those found in the rhizosphere, on the SeO3/SeO4 distribution. Jackland (Typic Hapludalf), Myersville (Ultic Hapludalf), Christiana (Aeric Paleaquult), and Evesboro (Typic Quartizipsamment) A and B horizon soil samples with and without prior Mn oxide reduction were incubated aerobically for 10 d with 0.1 mmol kg-1 SeO3 and 0 or 25 mmol kg-1 of ascorbic acid, gallic acid, oxalic acid, or citric acid. Selenite was also added to BHM (10 mmol kg-1) with 0 or 0.1 mmol kg-1 ascorbic acid. The availability of Se for plant uptake as a result of root-soil interactions was examined using growth chamber studies with barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) seedlings grown in 150-mL cone-shaped containers to maximize root-soil surface interactions and to create ‘rhizosphere’ soil throughout the root zone. In the BHM system ascorbic acid increased oxidation of SeO3 to SeO4 to 33% of added SeO3. In the presence of ascorbic and gallic acids and Mn oxides, oxidation of SeO3 to SeO4 occurred in the B horizons of all the soils and in the A horizons of Jackland and Myersville soils. Removal of Mn oxides decreased the oxidation in some samples. Wheat and barley plants were able to accumulate up to 20 μmol Se kg-1 from the Jackland soil when soluble Se was not measurable. The root-soil interactions in the Jackland soil with barley and wheat provided the plant with Se from insoluble sources. The results also indicate that Mn oxides coming in contact with reducing root exudates have a greater ability to oxidize SeO3 to SeO4. Thus, rhizosphere processes play an important role in the availability of Se for plant uptake.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00007911
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  • 74
    Digitale Medien
    Digitale Medien
    Root growth and nitrogen uptake in sycamore (Acer pseudoplantanus L.) seedlings in relation to nitrogen supply (1994)
    Springer
    Plant and soil 158 (1994), S. 233-238 
    Details
    ISSN: 1573-5036
    Schlagwort(e): nitrogen ; precoditioning ; roots ; sycamore
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Acer pseudoplatanus L. trees were grown in sand culture for 2 years and, in 1988, supplied with either 1.0 mol N m-3 (low N) or 6.0 mol N m-3 (high N) to precondition their growth. In 1989, the same trees received either high or low nitrogen, producing four treatments; High N in 1988/High N in 1989; High N in 1988/Low N in 1989; Low N in 1988/Low N in 1989; and Low N in 1988/High N in 1989. Plant growth was affected by N supply in both years. In 1989 the Low N/High N treated trees had the same overall mass, leaf mass and stem girth as the High N/High N treatment. Early spring growth of foliage and roots was conditional on nitrogen supplied in the previous season. Later, the rapid increases in leaf, stem and root growth under high N was through root uptake. Internal partitioning of growth was affected, with the Low N/High N treatment producing more new leaves on axillary shoots, and more new white roots on existing structures, than the Low N/Low N treatment. Despite effects of the N preconditioning on the structure of both canopy and root system, nitrogen uptake was solely dependent on the current nitrogen supply.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00009498
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  • 75
    Digitale Medien
    Digitale Medien
    Triphenyltetrazolium chloride as an indicator of fine-root vitality and environmental stress in coniferous forest stands: Applications and limitations (1994)
    Springer
    Plant and soil 159 (1994), S. 297-300 
    Details
    ISSN: 1573-5036
    Schlagwort(e): enzymes ; fine root vitality ; nitrogen ; Picea abies ; Pinus sylvestris ; triphenyltetrazolium chloride
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The present study is an attempt to investigate whether triphenyltetrazolium chloride (TTC), a chemical compound which measures dehydrogenase activity, could be used to study fine-root vitality from two different points of view: (i) in relation to ageing; (ii) as an indicator of environmental stress, in this case of excess nitrogen. The study was performed with excavated fine-roots from middle-aged Norway spruce and Scots pine stands. The ageing aspect was investigated by applying TTC to fine roots separated into different vitality classes, based on certain morphological characteristics. A significant difference in activity was demonstrated only in the case of roots that could be referred to as living and dead, respectively. The use of TTC on fine roots grown at different nitrogen supply levels indicates a possible increase in dehydrogenase activity with increasing nitrogen supply.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00009293
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  • 76
    Digitale Medien
    Digitale Medien
    Colonisation of wheat by VA-mycorrhizal fungi was found to be higher on a farm managed in an organic manner than on a conventional neighbour (1994)
    Springer
    Plant and soil 160 (1994), S. 33-40 
    Details
    ISSN: 1573-5036
    Schlagwort(e): organic agriculture ; phosphorus ; rock phosphate ; VA-mycorrhizas ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Levels of colonisation by vesicular-arbuscular (VA)-mycorrhizal fungi were compared between adjacent farms, one operated in a conventional manner and the other run according to organic farming principles. Wheat grown on the organic farm was found to have VA-mycorrhizal colonisation levels consistently 2 to 3 times higher than wheat on the conventional farm. Glasshouse and field trials indicated that the lower colonisation levels on the conventional farm were due to continual use of fertiliser containing soluble phosphorus (P). The fertiliser appeared to have an immediate negative effect on the rate of colonisation, and also appeared to have a long term negative effect through maintaining higher levels of soluble P in the soil, and by decreasing inoculum levels. Use of the relatively insoluble reactive rock phosphate fertiliser on the organic farm did not decrease levels of VA-mycorrhizas. Colonisation levels did not vary between wheat varieties, and herbicides and seed dressings were also not found to be having any significant effect on levels of colonisation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00150343
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  • 77
    Digitale Medien
    Digitale Medien
    Aluminum-induced deposition of (1,3)-β-glucans (callose) inTriticum aestivum L. (1994)
    Springer
    Plant and soil 162 (1994), S. 273-280 
    Details
    ISSN: 1573-5036
    Schlagwort(e): aluminum resistance ; (1, 3)-β-glucans ; callose ; roots ; stress indicator ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Aluminum (Al)-induced damage to leaves and roots of two Al-resistant (cv. Atlas 66, experimental line PT741) and two Al-sensitive (cv. Scout 66, cv. Katepwa) lines ofTriticum aestivum L. was estimated using the deposition of (1, 3)-β-glucans (callose) as a marker for injury. Two-day-old seedlings were grown for forty hours in nutrient solutions with or without added Al, and callose deposition was quantified by spectrofluorometry (0–1000 µM Al) and localized by fluorescence microscopy (0 and 400 µM Al). Results suggested that Al caused little damage to leaves. No callose was observed in leaves with up to 400 µM Al treatment. In contrast, root callose concentration increased with Al treatment, especially in the Al-sensitive lines. At 400 µM Al, root callose concentration of Al-sensitive Scout 66 was nearly four-fold that of Al-resistant Atlas 66. After Al treatment, large callose deposits were observed in the root cap, epidermis and outer cortex of root tips of Scout 66, but not Atlas 66. The identity of callose was confirmed by a reduced fluorescence in Al-treated roots: firstly, after adding an inhibitor of callose synthesis (2-deoxy-D-glucose) to the nutrient solution, and secondly, after incubating root sections with the callosedegrading enzyme β-D-glucoside glucohydrolase [EC 3.2.1.21]. Root callose deposition may be a good marker for Al-induced injury due to its early detection by spectrofluorometry and its close association with stress perception.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01347714
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  • 78
    Digitale Medien
    Digitale Medien
    Gravitropic response growth angle and vertical distribution of roots of wheat (Triticum aestivum L.) (1994)
    Springer
    Plant and soil 165 (1994), S. 323-326 
    Details
    ISSN: 1573-5036
    Schlagwort(e): genotype ; gravitropic response ; root depth index (RDI)_ ; root growth angle ; root vertical distribution ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Recent work on root distribution, growth angles and gravitropic responses in Japanese cultivars of winter wheat are reviewed. Vertical distribution of roots, which influences the environmental stress tolerance of plants, was observed in the 12 Japanese cultivars in the field. The root depth index (RDI: the depth at which 50% of the root length has been reached) differed among the cultivars at the stem elongation stage. Since the RDI was closely related to the growth angle of seminal roots obtained in a pot experiment, it was assumed that growth angle is useful for predicting vertical root distribution among wheat genotypes. Gravitropic responses of the primary seminal root of 133 Japanese wheat cultivars assessed by measuring the growth angle in agar medium, were larger in the northern Japanese cultivars and smaller in the southern ones. It was also found that the geographical variation resulted from the wheat breeding process, i.e. genotypes with limited gravitropic responses of roots had been selected in the southern part of Japan where excessive soil moisture is one of the most serious problems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00008076
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  • 79
    Digitale Medien
    Digitale Medien
    Losses of14C from roots of pulse-labelled wheat and barley during washing from soil (1994)
    Springer
    Plant and soil 166 (1994), S. 93-99 
    Details
    ISSN: 1573-5036
    Schlagwort(e): barley ; 14C ; pulse-labelling ; roots ; washing losses ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In crop carbon budget studies losses of root material during storage and washing of samples may cause considerable errors. To correct data from field experiments where rhizosphere C fluxes in wheat and barley were determined by14C pulse-labelling at different development stages, experiments were performed to quantify losses of14C from roots during washing. Losses of14C from wheat roots grown on nutrient solution and stored in different ways, decreased from on average 45% of total14C content 8 days after labelling to 27% after 21 days. This decrease was probably related to the incorporation of14C into structural compounds. During washing of oven-dried soil cores of held-grown wheat and barley 3 weeks after labelling, different size classes of losses of14C from the roots increased substantially with the development stage of the crop at labelling. The 0.3–0.6 mm size class increased from 5% of the14C in roots 〉 0.3 mm in young plants to 25% at ripening, and the 〈 0.3 mm size class increased from 8 to 41% of total14C content. The latter size class was, however, determined by washing handpicked roots and may therefore partly consist of adhering exudates, mucilages and microorganisms. The effect of development stage on root washing losses was attributed to root senescence which increases the fragility of roots. Thus, especially at the rate development stages root washing losses caused a severe underestimation of the root14C content. However, with these results the14C distribution patterns of the field experiments could be adequately corrected.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02185485
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  • 80
    Digitale Medien
    Digitale Medien
    Differences in the metabolic responses of root tips of wheat and rye to aluminium stress (1994)
    Springer
    Plant and soil 167 (1994), S. 165-171 
    Details
    ISSN: 1573-5036
    Schlagwort(e): aluminium tolerance ; enzymes ; root tips ; rye ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effects of aluminium (Al) ions on the metabolism of root apical meristems were examined in 4-day-old seedlings of two cereals which differed in their tolerance to Al: wheat cv. Grana (Al-sensitive) and rye cv. Dańkowskie Nowe (Al tolerant). During a 24 h incubation period in nutrient solutions containing 0.15 mM and 1.0 mM of Al for wheat and rye, respectively, the activity of first two enzymes in the pentose phosphate pathway (G-6-PDH and 6-PGDH) decreased in the sensitive cultivar. In the tolerant cultivar activities of these enzymes increased initially, then decreased slightly, and were at control levels after 24 h. In the Al-sensitive wheat cultivar a 50% reduction in the activity of 6-phosphogluconate dehydrogenase was observed in the presence of Al. Changes in enzyme activity were accompanied by changes in levels of G-6-P- the initial substrate in the pentose phosphate pathway. When wheat was exposed for 16 h to a nutrient solution containing aluminium, a 90% reduction in G-6-P concentration was observed. In the Al-tolerant rye cultivar, an increase and subsequently a slight decrease in G-6-P concentration was detected, and after 16 h of Al-stress the concentration of this substrate was still higher than in control plants. This dramatic Al-induced decrease in G-6-P concentration in the Al-sensitive wheat cultivar was associated with a decrease in both the concentration of glucose in the root tips as well as the activity of hexokinase, an enzyme which is responsible for phosphorylation of glucose to G-6-P. However, in the Al-tolerant rye cultivar, the activity of this enzyme remained at the level of control plants during Al-treatment, and the decrease in the concentration of glucose occurred at a much slower rate than in wheat. These results suggest that aluminium ions change cellular metabolism of both wheat and rye root tips. In the Al-sensitive wheat cultivar, irreversible disturbances induced by low doses of Al in the nutrient solution appear very quickly, whereas in the Al-tolerant rye cultivar, cellular metabolism, even under severe stress conditions, is maintained for a long time at a level which allows for root elongation to continue.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01587612
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  • 81
    Digitale Medien
    Digitale Medien
    C-band polymorphism and structural rearrangements detected in common wheat (Triticum aestivum) (1994)
    Springer
    Euphytica 78 (1994), S. 1-5 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; C-band polymorphism ; structural rearrangements ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Giemsa C-banding allows for the identification of all 21 chromosome pairs of hexaploid wheat. However, variation in banding patterns of individual chromosomes and structural rearrangements exist between different cultivars making chromosome identification more difficult. The paper summarizes the available data on C-band polymorphism and structural rearrangement present in wheat cultivars and germplasms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00021392
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  • 82
    Digitale Medien
    Digitale Medien
    The effect of temperature on seed set and embryo development in reciprocal crosses of wheat and barley (1994)
    Springer
    Euphytica 78 (1994), S. 53-58 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Hordeum vulgare ; barley ; intergeneric hybridization ; influence of temperature ; embryo development
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The effect of temperature on seed set and embryo development in reciprocal crosses of barley and wheat was assessed in crosses involving two spring barley varieties (Betzes, Martonvásári 50) and one wheat variety (Chinese Spring). Detached tillers placed in nutrient solution were pollinated in controlled environments at constant day-night temperature regimes (12, 15, 18 and 21° C) with a light intensity of 30,000 lux and a relative humidity of 80%. When barley was used as the female, lower temperatures (12 and 15° C) produced the maximum seed set, whereas for the reciprocal cross, the highest temperature (21° C) produced the best seed set in the Chinese Spring × Betzes combination. Low temperature retarded the embryo development. The highest numbers of hybrid plants were produced at 18° C and 21° C in the barley × wheat cross and in the wheat × barley cross, respectively. Embryos of about 1.5 mm length in the barley × wheat cross, and of about 1.0 mm length in the wheat × barley cross germinated successfully. The smallest embryo giving rise to hybrid plants was 0.57 mm in the barley × wheat cross and 0.51 mm in the wheat × barley cross.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00021397
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  • 83
    Digitale Medien
    Digitale Medien
    Scion-rootstock relationships with respect to height growth and foliar concentrations of nitrogen and phosphorus in reciprocal grafts of Pinus caribaea var. hondurensis (1994)
    Springer
    New forests 8 (1994), S. 71-79 
    Details
    ISSN: 1573-5095
    Schlagwort(e): foliage ; grafting ; nitrogen ; phosphorus ; Pinus caribaea ; rootstock ; scion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Both scion and rootstock clones significantly influenced scion elongation and concentrations of nitrogen and phosphorus in the scion foliage. Scion clone was the more important determinant. Scion clone × rootstock clone interactions were not significant. The ability of a clone to elongate as a scion was not correlated with its capacity to promote or retard scion elongation when used as a rootstock. Genetic differences in foliar nutrient concentrations appeared to reflect levels of nutrient demand, rather than the ability of roots to absorb nutrients. Nutrient demand of the rootstock can also explain negative correlations between nitrogen levels in rootstock clones and levels of both nitrogen and phosphorus in the scions. There was no significant relationship between scion elongation and foliar nitrogen concentrations of either rootstock or scion. The weak relationship between scion elongation and concentration of phosphorus in the rootstock apparently resulted from tissue dilution.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00034132
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  • 84
    Digitale Medien
    Digitale Medien
    Evaluation of Chinese Triticeae for resistance to Barley Yellow Dwarf Virus (BYDV) (1994)
    Springer
    Genetic resources and crop evolution 41 (1994), S. 35-41 
    Details
    ISSN: 1573-5109
    Schlagwort(e): wheat ; grass ; wide crossing ; China ; Barley Yellow Dwarf Virus (BYDV) ; luteovirus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Barley Yellow Dwarf Virus (BYDV) is recognised as a major pathological constraint to cereal production in northern China and several widespread epidemics have been reported. The host range of BYDV includes not only cereals but many grasses. The indigenous Triticeae of northern China have likely been exposed to significant disease pressure from BYDV and therefore may be a potential source of BYDV resistance for cereal improvement. A wide range of Triticeae accessions collected over three expeditions in northern China were evaluated for resistance to BYDV. Seedlings were artificially inoculated and virus levels then assayed by ELISA. Resistance and immunity to BYDV were found to be widely distributed among the seven genera of Triticeae included in the screening. A high proportion of resistant and immune accessions was found in the genera Hordeum, Leymus, Elymus and Elytrigia. The wide range of reaction types to BYDV found within many species, and even between accessions of some species, indicates that natural selection for BYDV resistance may have been relatively recent in the Chinese Triticeae. A high proportion of resistance and/or immunity was found in Xinjiang compared to the general distribution. From the Chinese Triticeae tested the Leymus species may be the most appropriate material to initiate transfer of BYDV resistance to wheat.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00051421
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  • 85
    Digitale Medien
    Digitale Medien
    Ethylene as promoter of wheat grain maturation and ear senescence (1994)
    Springer
    Plant growth regulation 15 (1994), S. 107-112 
    Details
    ISSN: 1573-5087
    Schlagwort(e): aminoethoxyvinylglycine ; ear senescence ; ethephon ; ethylene ; grain maturation ; silver thiosulfate ; Triticum aestivum ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract This work was aimed at testing the involvement of ethylene in the maturation of grain and senescence of the foliar structures of the wheat inflorescence. Whole wheat ears emitted ethylene to the atmosphere. From pre-anthesis, ethylene emission progressively increased from 0.76 nl g−1FW h−1 to a peak 1.53 nl g−1FW h−1 at the hard dough stage of the grains, to fall to a minimum of 0.10 nl g−1FW h−1 at the dormant seed stage. Ethephon increased the ethylene release, hastened the process of grain maturation and senescence of the ears. Aminoethoxyvinylglycine and silver thiosulfate produced the opposite effects. It is concluded that ethylene plays a role in grain maturation and in the senescence of the green bracts of the inflorescence.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00024098
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  • 86
    Digitale Medien
    Digitale Medien
    Gibberellins and α-amylase gene expression in germinating wheat grains (1994)
    Springer
    Plant growth regulation 15 (1994), S. 261-270 
    Details
    ISSN: 1573-5087
    Schlagwort(e): abscisic acid ; α-amylase ; germination ; gibberellin(s) ; paclobutrazol ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Gibberellins (GAs), GA8, GA17, GA19, GA20, GA29, and GA79 were identified by full-scan gas chromatography-mass spectrometry in a purified acidic fraction and GA8, GA20, GA79, and GA90 in a hydrolysed conjugate fraction from mature wheat grains. Gibberellin A20-13-O-glucoside was also quantified directly as the permethyl derivative in dry seed. The scutellum was identified as the major site of de novo GA biosynthesis by measuring ent-kaurene accumulation in vivo in grains treated with 2S,3S-paclobutrazol. Several GAs of the early 13-hydroxylation GA pathway began to accumulate in the axis and scutellum between 24 and 48 hours in untreated grains germinated at 15°C. Bioactive GA1 and GA3 also increased in the endosperm during this period, whereas abscisic acid contents of embryo and endosperm declined rapidly over 48 hours following imbibition. Treating grains with 2S,3S-paclobutrazol reduced GA1 plus GA3 content of scutella by 70–80% over 4 days without affecting significantly the steady-state pool of α-amylase mRNA transcripts. In contrast, a 50–80% reduction in the content of bioactive GAs in the endosperm was associated with a 70–78% decrease in transcripts for both α-amylase gene families in aleurones of paclobutrazol-treated grains. It was concluded that the initiation of α-amylase gene expression in wheat scutella was independent of de novo GA biosynthesis, whereas that in the aleurone was largely dependent on embryo-produced GAs.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00029899
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  • 87
    Digitale Medien
    Digitale Medien
    Crop nitrogen utilization and soil nitrate loss in a lettuce field (1994)
    Springer
    Nutrient cycling in agroecosystems 37 (1994), S. 93-105 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Erosion/Productivity Impact Calculator (EPIC) model ; leaching ; lettuce ; net N mineralization ; nitrate ; nitrogen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Low N use efficiency and high nitrate (NO 3 - ) pollution potentials are problems in intensive vegetable production systems. The purpose of this study was to quantify N utilization by lettuce (Lactuca sativa L. cv Salinas), and identify periods of NO 3 - loss in an on-farm study in the Salinas Valley in coastal California. During autumn and winter, surface moisture remained low, and NO 3 - concentrations increased, reflecting high net mineralizable N, as determined by anaerobic incubation, and nitrification potential, as determined by the chlorate inhibition method. At the onset of a large winter storm, tracer levels of15NO 3 - were injected in the top 5 mm of soil in 30 cm-deep cylinders. After two weeks, most of the15N was present as15NO 3 - at 10–30 cm depth. By difference, losses to denitrification accounted for ~ 25% of the surface-applied15N. Leaching below 30 cm did not occur, since no15N enrichment of NO 3 - -N was measured in anion-exchange resin membranes placed at the base of each cylinder. During the crop period, NO 3 - losses were most pronounced after irrigation events. Uptake of N by two crops of lettuce (above- and belowground material) was approximately equal to fertilizer inputs, yet simulation of N fates by the Erosion/Productivity Impact Calculator (EPIC) model indicated losses of 14.6 g-N m−2 by leaching and 2.5 g-N m−2 by denitrification during the 6-month crop period. The large NO 3 - losses can be attributed to accumulation of soil NO 3 - during winter that was leached or denitrified during the irrigated crop period.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00748550
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  • 88
    Digitale Medien
    Digitale Medien
    Effectiveness of different phosphatic fertilizers measured using labelled superphosphate and phosphorus taken up by plants (1994)
    Springer
    Nutrient cycling in agroecosystems 39 (1994), S. 31-37 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Compost ; diammonium phosphate ; phosphorus availability ; fertilizer effectiveness ; 32P ; rock phosphate ; superphosphate ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The agronomic effectiveness of three P fertilizers (diamonium phosphate, rock phosphate and compost) was studied in a greenhouse experiment using wheat. A radioisotopic method, using triple superphosphate labelled with32P, was used to evaluate the P in dried tops that was derived from i) the soil, ii) labelled superphosphate and iii) the fertilizer being studied. The ratio between P uptake from each fertilizer and P uptake from the soil was used to compare the effectiveness of the different fertilizers. P derived from diammonium phosphate was greater than P derived from the soil, except in one soil. P derived from rock phosphate was always lower than P derived from the soil. The effectiveness of compost depended on soil type. Compost can produce two kind of effects: i) a direct P contribution and ii) an indirect effect improving P uptake from the soil. The radioisotopic method can be used to study the effectiveness of fertilizers even when there are no differences in yield.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750154
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  • 89
    Digitale Medien
    Digitale Medien
    Coupling of dry matter and nitrogen accumulation in ryegrass (1994)
    Springer
    Nutrient cycling in agroecosystems 40 (1994), S. 105-108 
    Details
    ISSN: 1573-0867
    Schlagwort(e): annual ryegrass ; dry matter ; logistic ; model ; nitrogen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The logistic model has proven very useful in relating dry matter production of warm season perennial forage grasses to applied nitrogen. A recent extension of the model coupled dry matter and plant N accumulation through a common response coefficient c. The objective of this analysis was to apply the extended logistic model to cool season Gulf annual ryegrass (Lolium multiflorum Lam.) and to establish a common response coefficient c between accumulation of dry matter and plant N. Analysis of variance established the validity of this hypothesis. The model accurately described response of dry matter, plant N removal, and plant N concentration to applied N, with an overall correlation coefficient of 0.9954. Furthermore, the model closely described the relationship between yield and plant N removal, as well as between plant N concentration and plant N removal. The logistic equation is well-behaved and simple to use on a pocket calculator. It can be used to estimate yields and plant N removal in evaluation of agricultural production and environmental quality.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750094
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  • 90
    Digitale Medien
    Digitale Medien
    Large granules, nests or bands: Methods of increasing efficiency of fall-applied urea for small cereal grains in North America (1994)
    Springer
    Nutrient cycling in agroecosystems 38 (1994), S. 61-87 
    Details
    ISSN: 1573-0867
    Schlagwort(e): Band placement ; barley ; cereal grains ; fall-applied N ; fertilizer efficiency ; large urea granules ; LUG ; method of placement ; nest placement ; nitrification ; time of application ; urea fertilizer ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In North America where the climate is cool enough only one crop is grown yearly, N fertilizers are sometimes applied in the previous fall rather than in the spring for fall- or spring-sown cereal grains. However, in areas where snow accumulates in winter, fall application of N fertilizers is generally inferior to spring application. Substantial nitrification takes place in winter and subsequent N loss occurs primarily in early spring by denitrification after the snow melt. Immobilization of N is also greater with fall- than spring-applied N fertilizers. Nitrogen is more efficiently retained in the soil as NH4 and thus more effectively used by plants if formation of nitrite (NO2) and NO3 is reduced or prevented by inhibiting nitrification. The nitrification is reduced when urea is placed in bands, because of high pH, ammonia concentration and osmotic pressure in the soil. The rate of nitrification is further reduced when urea is placed in widely-spaced nests (a number of urea prills placed together at a point below the soil surface) or as large urea granules (LUG) by reducing contact between the nitrifying bacteria and the NH4 released upon urea hydrolysis. A further reduction in nitrification from LUG can be obtained by addition of chemical nitrification inhibitors (such as dicyandiamide (DCD)) to LUG. The concentration of a chemical inhibitor required to suppress nitrification decreases with increasing granule size. The small soil-fertilizer interaction zone with placement of urea in nests or as LUG also reduces immobilization of fertilizer N, especially in soils amended with crop residues. The efficiency of fall-applied N is improved greatly by placing urea in nests or as LUG for small cereal grains. Yields of spring-sown barley from nests of urea or LUG applied in the fall are close to those obtained with spring-applied urea prills incorporated into the soil. Delaying urea application until close to freeze-up is also improved the efficiency of fall-applied N. This increased effectiveness of urea nests or LUG is due to slower nitrification, lower N loss over the winter by denitrification, and reduced immobilization of applied N. Fall application of LUG containing low rates of DCD slows nitrification, reduces over-winter N loss, and causes further improvement in yield and N uptake of winter wheat compared to urea as LUG alone in experiments in Ontario; in other experiments in Alberta there is no yield advantage from using a nitrification inhibitor with LUG for barley. Placement of LUG or nests of urea in soil is an agronomically sound practice for reducing N losses. This practice can eliminate or reduce the amount of nitrification inhibitor necessary to improve the efficiency of fall-applied urea where losses of mineral N are a problem. The optimum size of urea nest or LUG, and optimum combination of LUG and an efficient nitrification inhibitor need to be determined for different crops under different agroclimatic conditions. The soil (texture, CEC, N status), plant (winter or spring crop, crop geometry, crop growth duration and cultivar) and climatic (temperature, amount and distribution of precipitation) factors should be taken into account during field evaluation of LUG. There is a need to conduct region-specific basic research to understand mechanisms and magnitudes of N transformations and N losses in a given ecosystem. Prediction of nitrification from LUG or urea nests in various environments is needed. In nitrification inhibition studies with LUG and chemical nitrification inhibitors, measurements of nitrifier activity will be useful. Finally, there is need for development of applicators for mechanical placement of LUG or urea prills in widely-spaced nests in soil.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00750063
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  • 91
    Digitale Medien
    Digitale Medien
    Effect of selenium-enriched calcium nitrate, top-dressed at different growth stages, on the selenium concentration in wheat (1994)
    Springer
    Nutrient cycling in agroecosystems 38 (1994), S. 199-203 
    Details
    ISSN: 1573-0867
    Schlagwort(e): calcium nitrate ; growth stages ; sodium selenate-enriched fertilizers ; Se concentration ; silty clay soil ; top-dressing ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A greenhouse experiment was conducted to evaluate the effect of Se contained in calcium nitrate, top-dressed at different growth stages, on the Se concentration in wheat (Triticum aestivum L.). Selenium as sodium selenate was added to Ca (NO3)2 and NPK (21-4-10) during the manufacturing process. A silty clay soil with soil pH of 6.1 was used. Four selenium treatments incorporated in Ca (NO3)2 were top-dressed at both the tillering and heading growth stages at rates of 0, 15, 30, and 45 mg kg−1 of Ca (NO3)2 fertilizer equivalent to about 0, 0.003, 0.007, 0.01 mg Se kg−1 soil, respectively. A fifth treatment of 20 mg Se kg−1 of NPK (21-4-10%) equivalent to 0.007 mg Se kg−1 soil was basal dressed at the time of sowing. Calcium nitrate with or without Se was top-dressed at the rate of 35 mg N kg−1. In addition all pots received a basal dose of N at the rate of 7 0 mg N kg−1 through a NPK(21-4-10) fertilizer. The Se-enriched Ca (NO3)2 increased the uptake and concentration of Se in wheat significantly (ρ〉0.05) with increasing concentration of Se in the fertilizer applied. The Se concentration in wheat grain increased from 〈1.1 to 468µg Se kg−1 in the first year when the concentration in the Se-enriched Ca (NO3)2 was increased from 0 to 45 mg Se kg−1 but the corresponding increase in the second and third year was lower. The Se concentration in the grain was more than twice of that in the straw. The uptake and concentration of Se in wheat, except in the second year, was generally higher when Se was top-dressed at heading as compared to that when it was top-dressed at tillering but the concentration differences between time of application were not statistically significant(ρ〉0.05). Basal application of Se-enriched NPK (0.007 mg Se kg−1 soil) was only half as effective as an equivalent rate of Se in top-dressed Seenriched Ca(NO3)2 in increasing the Se concentration in wheat and the concentration levels among these treatments were significantly (ρ〉0.01) different. It was concluded that topdressing of Se-enriched Ca(NO3)2 at 30 mg Se kg−1 is an effective method of application to increase the Se concentration in wheat grain to a level, 〉 100µg kg−1 dry matter, considered adequate for human consumption.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00749692
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  • 92
    Digitale Medien
    Digitale Medien
    Mycorrhizal dependency of micropropagated argan tree (Argania spinosa): II. Mineral nutrition (1994)
    Springer
    Agroforestry systems 27 (1994), S. 67-77 
    Details
    ISSN: 1572-9680
    Schlagwort(e): Argania spinosa ; micro-elements ; nitrogen ; phosphorus ; V.A. mycorrhization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Beschreibung / Inhaltsverzeichnis: Résumé L'influence de la mycorhization V.A. sur la nutrition minérale de 2 clones d'Arganier (Argania spinosa) a été étudiée sur des plantules micropropagées in vitro poussant en conditions contrôlées. L'inoculation (qui augmentait la production de matière sèche d'un facteur 4,5) accroit également la teneur des plantes en phosphore, notamment dans les feuilles, et les plantes mycorhizées mobilisent 15 fois plus de phosphore que les plantes non inoculées. La teneur en azote est légèrement plus faible chez les plantes mycorhizées mais au total ces dernières exportent 3 fois plus d'azote. L'absorption des micro-éléments est aussi affectée par l'inoculation, qui accroit les teneurs des plantes en Fe, Zn et Cu. La nutrition minérale des deux clones étudiés semble affectée par le rapport racines/parties aériennes et d'autres caractéristiques génétiques, comme l'efficacité de translocation du fer. Ces résultats nous permettent de comprendre en quoi son système racinaire profond et mycorhizé permet à l'Arganier non seulement de pousser dans des zones arides aux sols pauvres, mais aussi d'améliorer la fertilité des couches supérieures du sol par l'effet litière.
    Notizen: Abstract The influence of V.A. mycorrhization on mineral nutrition of 2 clones ofArgania spinosa was studied with in-vitro micropropagated plantlets grown in confined medium under controlled conditions. Inoculation, which increased dry matter production by a factor of 4.5, also increased P concentration in the plant, especially in the leaves, and the mycorrhizal plants mobilized 15 times more P than control plants. N concentration was slightly lower in mycorrhizal plants, but total N content was 3 times higher. Uptake of micro elements was also affected, inoculation increasing plant Fe, Zn and Cu content. Mineral nutrition in the test clones seemed affected by root/shoot ratio and other genetically-related characteristics, such as Fe translocation efficiency. These results help us to understand how its deep mycorrhizal root system might allowArgania spinosa not only to grow in infertile arid areas but also to improve top-soil fertility by a litter effect.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00704835
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  • 93
    Digitale Medien
    Digitale Medien
    Effect of increasing distance fromAcacia nilotica trees on wheat yield (1994)
    Springer
    Agroforestry systems 25 (1994), S. 23-29 
    Details
    ISSN: 1572-9680
    Schlagwort(e): Acacia nilotica ; wheat ; border trees ; crop yield ; Pakistan
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Planting trees in the cultivated fields of Pakistan is a controversial topic between foresters and agriculturists. Some farmers believe that trees significantly reduce their crop yields; therefore they avoid planting trees in their fields. On the other hand, many foresters claim trees are beneficial for crops. This study was conducted to determine the influence of boundary trees (Acacia nilotica) on the growth and yield of associated wheat crops under irrigated conditions in Punjab, Pakistan. Results indicate that close proximity to trees adversely affected tillers/m2, weight/1000 grain and the grain yield of wheat planted up to a distance of 8.5 m from the trees. Plant height and grains/spike were least affected. In general, the growth and yield of wheat improved as distance from the tree increased. Tree size did not affect wheat height, tillers/m2, grains/spike or weight/1000 grain. The grain yields were slightly lower near the largest trees (50–54.9 cm DBH trees).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00705704
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  • 94
    Digitale Medien
    Digitale Medien
    Heterosis of grain weight in wheat hybrids with Triticum timopheevi cytoplasm (1994)
    Springer
    Euphytica 75 (1994), S. 189-193 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Grain filling characteristics ; heterosis ; Triticum timopheevi cytoplasm ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Two kinds of wheat hybrids with the same nuclear genotype but different cytoplasms (one with T.timopheevi cytoplasm, i.e., A/R, and the other with T.aestivum cytoplasm, i.e., B/R) were produced by two 3 × 5 incomplete diallel crosses of 3 A-lines, 3 corresponding B-lines and 5 R-lines, respectively. Experimental results did not show significant differences between the hybrids of A/R and B/R in grain filling characteristics and grain weight. The beterosis of grain weight seems mainly determined by the nuclear genotype. Although the seeds set on most A-lines were shrivelled, such a phenomenon was not found in grains set on F1. The duration of the lag period (D1) and the average grain filling rates during the linear period and the mature period (i.e., FR2 and FR3) were significantly and positively related to 1000-grain weight. It was in these factors that most hybrids displayed clear mid-parent (MP) heterosis. The amount of grain weight heterosis was not significantly related to MP value. This indicates that the grain weight heterosis of wheat hybrids will not decrease with an increase of the MP value.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00025603
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  • 95
    Digitale Medien
    Digitale Medien
    Genetics of leaf rust resistance in 13 accessions of the Watkins wheat collection (1994)
    Springer
    Euphytica 80 (1994), S. 151-155 
    Details
    ISSN: 1573-5060
    Schlagwort(e): leaf rust resistance ; Puccinia recondita ; Triticum aestivum ; wheat ; genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The inheritance of leaf rust resistance was studied in 13 accessions of the A.E. Watkins wheat collection. Eight of the accessions (V409, V624, V628, V712, V731, V734, V745, and V855) were shown to have gene Lr33 and four of these (V409, V624, V628, and V731) also have LrW. Accessions V624 and V338 have LrB, and V377 and V488 have Lr11. V46 has an unidentified gene that gives an intermediate level of resistance. V860 has a partially dominant gene that gives a fleck reaction to avirulent isolates in the seedling stage. This gene is different from LrW and may be previously unidentified. It has been assigned the temporary gene symbol LrW2. In addition to seedling-effective genes, V46, V731, and V745 may have Lr34 and V745 may have Lr13. The adult-plant resistance in V488, V624, and V860 could not be identified. Seedling gene LrW2 and some of the adult-plant resistance should be useful sources of resistance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00039311
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  • 96
    Digitale Medien
    Digitale Medien
    Evolution of virulence patterns in yellow rust races and its implications for Ereeding for resistance in wheat in Kenya (1994)
    Springer
    Euphytica 80 (1994), S. 165-170 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Puccinia striiformis ; yellow rust ; durable resistance ; race-specific resistance ; residual resistance ; races ; virulence, Kenya
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Virulence patterns of yellow rust isolates collected in Kenya between 1986–1989 were compared with earlier results. The number of virulence factors per race and the range in virulence factors both increased considerably. Before 1976 races carried on average 4.5 to 5.0 virulence factors, whereas the races after 1986 had a mean of 6.5 virulence factors. The range in the number of virulence factors increased from some seven to eight in the first period to 12 in the second out of the 17 evaluated. In the period 1986–1989 another three virulence factors (2, 9 and A) were assessed. All three occurred at a high frequency. Virulence neutralizing the resistance genes Yr2, Yr2+, Yr6, Yr6+, Yr7, Yr7+, Yr8, Yr9, Yr9+ and those in the cultivars Anza (A), Strubes Dickkopf (SD) and Suwon92/Omar (SU) occurred at a high frequency, while virulence for Yr3V, Yr4+, Yr5, CV and SP (resistance in Carstens V and Spaldings Prolific resp.) were not found. The remaining three virulence factors for Yr1, 10 and 3N were rare. In the past ten years the resistance of most released cultivars became ineffective in less than six years. They were shown to carry race-specific major resistance genes such as Yr7+, Yr9+, SD and A. However, in the field, the resistance of the cultivars was not completely neutralized. A residual resistance, ranging from moderate to fairly high, was observed in all cultivars in which the major gene resistances were neutralized by corresponding virulence genes. Other wheat cultivars such as Africa Mayo, Kenya Kudu, Enkoy, Kenya Leopard, Bounty, Frontatch, Bonny and Kenya Plume appeared to keep their resistance over a condiserable period of time. They are considered to be durably resistant to the Kenyan yellow rust populations. This form of resistance, together with the residual resistance, can be recommended for use in breeding programmes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00039647
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  • 97
    Digitale Medien
    Digitale Medien
    Isotope ratios and concentrations of sulfur and nitrogen in needles and soils of Picea abies stands as influenced by atmospheric deposition of sulfur and nitrogen compounds (1994)
    Springer
    Plant and soil 164 (1994), S. 267-281 
    Details
    ISSN: 1573-5036
    Schlagwort(e): atmospheric deposition ; δ15N ; δ34S ; forest decline ; nitrogen ; Picea abies ; stable isotopes ; sulfur
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Concentrations and natural isotope abundance of total sulfur and nitrogen as well as sulfate and nitrate concentrations were measured in needles of different age classes and in soil samples of different horizons from a healthy and a declining Norway spruce (Picea abies (L.) Karst.) forest in the Fichtelgebirge (NE Bavaria, Germany), in order to study the fate of atmospheric depositions of sulfur and nitrogen compounds. The mean δ15N of the needles ranged between −3.7 and −2.1 ‰ and for δ34S a range between −0.4 and +0.9 ‰ was observed. δ34S and sulfur concentrations in the needles of both stands increased continuously with needle age and thus, were closely correlated. The δ15N values of the needles showed an initial decrease followed by an increase with needle age. The healthy stand showed more negative δ15N values in old needles than the declining stand. Nitrogen concentrations decreased with needle age. For soil samples at both sites the mean δ15N and δ34S values increased from −3 ‰ (δ15N) or +0.9 ‰ (δ34S) in the uppermost organic layer to about +4 ‰ (δ15N) or +4.5 ‰ (δ34S) in the mineral soil. This depth-dependent increase in abundance of 15N and 34S was accompanied by a decrease in total nitrogen and sulfur concentrations in the soil. δ15N values and nitrogen concentrations were closely correlated (slope −0.0061 ‰ δ15N per μmol eq N gdw −1), and δ34S values were linearly correlated with sulfur concentrations (slope −0.0576 ‰ δ34S per μmol eq S gdw −1). It follows that in the same soil samples sulfur concentrations were linearly correlated with the nitrogen concentrations (slope 0.0527), and δ34S values were linearly correlated with δ15N values (slope 0.459). A correlation of the sulfur and nitrogen isotope abundances on a Δ basis (which considers the different relative frequencies of 15N and 34S), however, revealed an isotope fractionation that was higher by a factor of 5 for sulfur than for nitrogen (slope 5.292). These correlations indicate a long term synchronous mineralization of organic nitrogen and sulfur compounds in the soil accompanied by element-specific isotope fractionations. Based on different sulfur isotope abundance of the soil (δ34S=0.9 ‰ for total sulfur of the organic layer was assumed to be equivalent to about −1.0 ‰ for soil sulfate) and of the atmospheric SO2 deposition (δ34S=2.0 ‰ at the healthy site and 2.3 ‰ at the declining site) the contribution of atmospheric SO2 to total sulfur of the needles was estimated. This contribution increased from about 20 % in current-year needles to more than 50 % in 3-year-old needles. The proportion of sulfur from atmospheric deposition was equivalent to the age dependent sulfate accumulation in the needles. In contrast to the accumulation of atmospheric sulfur compounds nitrogen compounds from atmospheric deposition were metabolized and were used for growth. The implications of both responses to atmospheric deposition are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00010079
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  • 98
    Digitale Medien
    Digitale Medien
    Influence of nitrogen, plant growth stage, and environment on charcoal rot of grain sorghum caused by Macrophomina phaseolina (Tassi) Goid (1994)
    Springer
    Plant and soil 158 (1994), S. 203-210 
    Details
    ISSN: 1573-5036
    Schlagwort(e): charcoal rot ; Macrophomina phaseolina ; nitrogen ; NH4NO3 ; Sorghum bicolor
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Colonization of sorghum by Macrophomina phaseolina in field plots was determined at nitrogen fertilization rates of 0, 56, 112, and 168 kg ha-1 in 1988 and 0, 84, 168, and 256 kg ha-1 in 1989. Above ground plant tissue and roots were sampled monthly to determine total nitrogen and percent colonization of root segments by natural inoculum. Root infection was not affected by nitrogen treatment, but was affected by growth stage and environment. High root infection occurred before reproductive development (growth stage 3) in 1988 and was associated with hot, dry weather early in the growing season. In 1989, when the weather was cool and wet, root infection began after reproductive development (growth stage 4). The effect of nitrogen treatments on lesion length was determined in sorghum stalks artificially inoculated with M. phaseolina. Lesion lengths were significantly affected by both nitrogen treatments and growth stage. Lesions were significantly longer with all nitrogen treatments at growth stage 9 than with the no-nitrogen treatment, and lesions tended to increase with increased levels of nitrogen fertilization. Significant increases in lesion length occurred between growth stages 5, 7, and 9 in 1988 and between 7 and 9 in 1989. This study demonstrates that nitrogen fertilization affects colonization of sorghum stalks but not root infection by M. phaseolina.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00009495
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  • 99
    Digitale Medien
    Digitale Medien
    Nitrogen mineralization and H+ transfers in a Scots pine (Pinus sylvestris L.) forest soil as affected by liming (1994)
    Springer
    Plant and soil 161 (1994), S. 209-218 
    Details
    ISSN: 1573-5036
    Schlagwort(e): ammonification ; H+ production ; in-situ incubation ; liming ; mineralization ; nitrification ; nitrogen ; Pinus sylvestris
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract H+ production due to N uptake in a mature Scots pine stand subjected to high NH4 + deposition was previously estimated to amount to approx. 2.2 kmol ha-1 y-1. The question whether H+ transfers related to N mineralization (ammonification and nitrification) offset or corroborate this proton production is investigated in the present research. To determine N mineralization, soil cores were used of which both ends were closed with layers of ion exchange resin (IER) to prevent influx and efflux of ions. The effect of liming on N mineralization and the resulting H+ production was investigated in 7 incubation periods of each ca. 8 wk. Because of its high mobility NO3 accumulated in both IER layers at the expense of that in the incubated forest floor and mineral soil. Net N mineralization in the soil cores as a whole amounted to 40 and 77 kg N ha-1 in 384 d in the control and limed plots, respectively. In both treatments ca. 65% of mineralized N was nitrified. H+ production due to N mineralization amounted to approx. 1.2 kmol ha-1 y-1 in the control and limed plots. Liming reduced the amount of C in the forest floor, but not forest floor mass, because of an increased mixing with mineral particles.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00046391
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  • 100
    Digitale Medien
    Digitale Medien
    Carbon translocation to the rhizosphere of maize and wheat and influence on the turnover of native soil organic matter at different soil nitrogen levels (1994)
    Springer
    Plant and soil 161 (1994), S. 233-240 
    Details
    ISSN: 1573-5036
    Schlagwort(e): C distribution ; native soil organic matter ; rhizosphere ; root released carbon ; wheat ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Wheat and maize were grown in a growth chamber with the atmospheric CO2 continuously labelled with 14C to study the translocation of assimilated carbon to the rhizosphere. Two different N levels in soil were applied. In maize 26–34% of the net assimilated 14C was translocated below ground, while in wheat higher values (40–58%) were found. However, due to the much higher shoot production in maize the total amount of carbon translocated below ground was similar to that of wheat. At high N relatively more of the C that was translocated to the root, was released into the soil due to increased root respiration and/or root exudation and subsequent microbial utilization and respiration. The evolution rate of unlabelled CO2 from the native soil organic matter decreased after about 25 days when wheat was grown at high N as compared to low N. This negative effect of high N in soil was not observed with maize.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00046394
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