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  • 36.40  (59)
  • Triticum aestivum  (49)
  • cell culture  (37)
  • Springer  (145)
  • American Institute of Physics (AIP)
  • Cell Press
  • 1990-1994  (145)
  • 1991  (145)
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  • Springer  (145)
  • American Institute of Physics (AIP)
  • Cell Press
  • Wiley-Blackwell  (7)
Erscheinungszeitraum
  • 1990-1994  (145)
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    Use of systemic insecticide to measure antixenosis to aphids in plant choice experiments (1991)
    Springer
    Entomologia experimentalis et applicata 58 (1991), S. 69-74 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Rhopalosiphum padi ; antixenosis ; plant resistance ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Antixenose gegenüberRhopalosiphum padi (L.) in den drei Weizensorten Timmo, Moghan 2 und Ommid, von denen die zwei letzteren Sorten aus dem Iran stammen, wurde unter Verwendung des systemischen Insektizids Pirimicarb gemessen. Jeweils zwei Pflanzen aus verschiedenen Sorten wurden als Paar verwendet (in allen Kombinationen der drei Sorten), pro Paar ein Topf mit Pirimicarb gegossen, und zwanzig Blattlaüse über Blattflächen von beiden Sorten gekäfigt. Ähnliche Versuche wurden auch ohne Insektizid ausgeführt. Beide Methoden zeigten deutliche Antixenose von Moghan 2 und Ommid in Vergleich mit Timmo. Die Insektizidmethode zeigte auch eine Bevorzugung von Moghan 2 gegenüber Ommid, ein Resultat, das mit der schon bekannten relativen Antibiose dieser zwei Sorten übereinstimmte, während sich ohne Insektizid kein solcher Unterschied erwies. Die statistische Analyse solcher Versuche mit einem Insektizid, die eine Modifikation der Berechnung des erwarteten Werts mit dem χ2 Test enthält, ist beschrieben.
    Notizen: Abstract Antixenosis in three wheat varieties (Timmo, Moghan 2 and Ommid) toRhopalosiphum padi (L.) was measured by pairing plants of any two varieties with one plant of each pair treated with a soil drench of the systemic insecticide pirimicarb. Aphids were then allowed access to equivalent leaf areas from the two plants in a leaf cage. The results were compared with similar choice experiments without insecticide. By either technique, the two Iranian varieties (Moghan 2 and Ommid) showed antixenosis in comparison with Timmo. The statistical analysis of the data, using a heterogeneity χ2 test, is described.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00163315
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  • 2
    Digitale Medien
    Digitale Medien
    Hydroxamic acids affecting barley yellow dwarf virus transmission by the aphid Rhopalosiphum padi (1991)
    Springer
    Entomologia experimentalis et applicata 59 (1991), S. 79-85 
    Details
    ISSN: 1570-7458
    Schlagwort(e): Wheat ; Triticum aestivum ; cereals ; Rhopalosiphum padi ; Aphididae ; barley yellow dwarf virus ; hydroxamic acids ; DIMBOA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract 2,4-Dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), a hydroxamic acid (Hx) occurring in wheat, was shown to deter feeding by the aphid Rhopalosiphum padi (L.), and to reduce BYDV transmission to the plant. Dual choice tests with wheat leaves showed the preferential settlement of aphids on leaves with lower levels of DIMBOA. Electric monitoring of aphid feeding behaviour showed that in seedlings with higher DIMBOA levels fewer aphids reached the phloem and they needed longer times to contact a phloem vessel than in those with lower levels. When aphids carrying BYDV were allowed to feed on wheat cultivars with different DIMBOA levels, fewer plants were infected with BYDV in the higher DIMBOA cultivars than in the lower ones. Preliminary field experiments showed a tendency for wheat cultivars with higher Hx levels to be more tolerant to infection by BYDV than lower Hx level ones.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00187969
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  • 3
    Digitale Medien
    Digitale Medien
    Coherent raman spectroscopy of nitrogen molecules and clusters in supersonic jets (1991)
    Springer
    Applied physics 52 (1991), S. 84-89 
    Details
    ISSN: 1432-0649
    Schlagwort(e): 36.40 ; 42.65 ; 47.40
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Coherent Stokes and anti-Stokes Raman scattering CSRS and CARS have been employed to study the spectroscopy of nitrogen molecules and clusters in the expansion of a supersonic jet. In the vibrational spectrum, at strong stagnation conditions, an intense redshifted peak is observed which can be assigned to the intramolecular vibrations in large N2 clusters having adopted the β-phase structure. Another weak feature is assigned to nitrogen clusters in the α-phase. In the rotational region of the spectrum only monomer features have been observed. The failing to observe librational motions is consistent with the finding that the nitrogen clusters are predominantly in the orientationally unordered β-phase. The low rotational temperature suggests supercooling of the β-phase.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00357660
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  • 4
    Digitale Medien
    Digitale Medien
    Laser-fluorescence diagnostics for condensation in laser-ablated copper plasmas (1991)
    Springer
    Applied physics 53 (1991), S. 353-361 
    Details
    ISSN: 1432-0649
    Schlagwort(e): 36.40
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We are investigating the thermodynamic conditions under which condensation occurs in laser ablated copper plasma plumes. The plasma is created by XeCl excimer laser ablation (308 nm, 300 mJ/pulse) at power densities from 500–1000 MW/cm2 into backing pressures of helium in the range 0–50 torr. We use laser-induced fluorescence (LIF) to probe velocity and relative density of both atomic copper and the copper dimer molecule, Cu2, which is formed during condensation onset. At low pressure (10 mtorr), the atomic Cu velocity peaks at approximately 2×106 cm/s. Copper dimer time-of-flight data suggest that condensation onset occurs after the Cu atoms have slowed very significantly. Excitation scans of the Cu2A-X (0,0) and (1,1) bands yield a rotational and vibrational temperature in the neighborhood of 300 K for all conditions studied. Such low temperatures support the theory that Cu2 is formed under thermally and translationally cold conditions. Direct laser beam absorption is used to determine the number density of atomic copper. Typical densities attained with 5 torr of helium backing gas are 6–8×1013 cm−3. Rayleigh scattering from particulate is easily observable under conditions favorable to particulate production.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00331827
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  • 5
    Digitale Medien
    Digitale Medien
    Differential expression of the psbB and psbH genes encoding the 47 kDa chlorophyll a-protein and the 10 kDa phosphoprotein of photosystem II during chloroplast development in wheat (1991)
    Springer
    Current genetics 19 (1991), S. 199-206 
    Details
    ISSN: 1432-0983
    Schlagwort(e): Light regulation ; psbN ; Triticum aestivum ; Etioplast
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The nucleotide sequence of a region of wheat chloroplast DNA containing the psbB gene for the 47 kDa chlorophyll a-binding protein of photosystem II has been determined. The gene encodes a polypeptide of 508 amino acid residues which is predicted to contain six hydrophobic membrane-spanning regions. The psbB gene is located 562 bp upstream of the psbH gene for the 10 kDa phosphoprotein of photosystem II. A small open reading frame of 38 codons is located between psbB and psbH, and on the opposite strand the psbN gene, encoding a photosystem II polypeptide of 43 amino acid residues, is located between orf38 and psbH. S1 nuclease mapping indicated that the 5′ ends of transcripts were located 371 and 183 bp upstream of the psbB translation initiation codon. Predominant transcripts of 2.1 kb and 1.8 kb for psbB and 0.4 kb for psbH were present in RNA isolated from etiolated and greening wheat seedlings. Immunodecoration of Western blots indicated that the 47 kDa polypeptide was absent, or present in very low amounts, in dark-grown tissue and accumulated on greening, whereas the 10 kDa polypeptide was present in similar amounts in both dark-grown and greening seedlings. The 10 kDa polypeptide was phosphorylated in vitro by incubating wheat etioplast membranes with [γ3 2P] ATP.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00336487
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  • 6
    Digitale Medien
    Digitale Medien
    Toxicity of the mycotoxins fumonisins B1 and B2 and Alternaria alternata f. sp. lycopersici toxin (AAL) in cultured mammalian cells (1991)
    Springer
    Mycopathologia 116 (1991), S. 97-104 
    Details
    ISSN: 1573-0832
    Schlagwort(e): Fumonisin B1 ; fumonisin B2 ; AAL toxin ; T-2 toxin ; mycotoxin ; Fusarium moniliforme ; bioassay ; cell culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Fumonisins B1 and B2 and AAL toxin are a series of structurally related mycotoxins. Fumonisins B1 and B2, produced by Fusarium moniliforme Sheldon induce toxic hepatitis and hepatomas in rats and leukoencephalomalacia in horses. The cancer-promotion assay which has been used to guide their purification is slow and consumes large amounts of sample. We have examined a series of cultured mammalian cell lines in order to develop a more rapid and sensitive bioassay system, which may be useful for examining structure-activity relationships and the mechanism(s) of action of these toxins. Of 9 rat hepatoma cell lines tested, all except the two most de-differentiated lines were sensitive to the three toxins, with a toxic response visible by 48 h. Approximate IC50 values for the most sensitive hepatoma line, H4TG, were 4, 2 and 10 μg/ml for fumonisins B1, B2 and AAL toxin, respectively „in 100 μl cultures. Among 15 cell lines from other sources, only MDCK dog kidney epithelial cells were sensitive (IC50 = 2.5, 2 and 5 μg/ml, respectively). Studies in co-cultures of sensitive and insensitive cell lines and in cultures of a sensitive cell line over a range of cell densities indicated that cytotoxicity of fumonisins B1 and B2 does not involve metabolite activation to a derivative stable enough to diffuse to adjacent cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00436371
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  • 7
    Digitale Medien
    Digitale Medien
    Modified culture method for human corneal epithelial cells (1991)
    Springer
    Methods in cell science 13 (1991), S. 45-48 
    Details
    ISSN: 1573-0603
    Schlagwort(e): cell culture ; corneal epithelium ; primary explant
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary An improved procedure for the primary culture of pure human corneal epithelial cells from corneal explants is described. Confluent monolayers of epithelial cells can be consistently produced from small segments of donor corneas regardless of donor age and without feeder layers. Incubating segments on collagen at the air-liquid interface significantly improves the yield of cells per cornea and shortens cell migration time as compared to culturing on plastic. Fibroblast contamination is eliminated by serum-free medium and confirmed by indirect immunofluorescent staining for keratin.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02388203
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  • 8
    Digitale Medien
    Digitale Medien
    Culture of human renal cortex epithelial cells (1991)
    Springer
    Methods in cell science 13 (1991), S. 143-147 
    Details
    ISSN: 1573-0603
    Schlagwort(e): kidney ; renal cortex ; proximal tubule ; enzymatic dissociation ; cell culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A procedure is described for the establishment and propagation of epithelial cell rich cultures derived from normal human kidney cortex (NHK-C cells). Cells are harvested from tissue fragments of donor human kidney by progressive enzymatic dissociation. NHK-C cultures are morphologically heterogeneous but exhibit, predominantly, the functional characteristics of cells of the kidney proximal tubule.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02388118
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  • 9
    Digitale Medien
    Digitale Medien
    Cluster emission under ion bombardment of metallic targets (1991)
    Springer
    Applied physics 52 (1991), S. 213-217 
    Details
    ISSN: 1432-0630
    Schlagwort(e): 36.40
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau , Physik
    Notizen: Abstract Mass spectroscopic studies of the neutral particles sputtered by Ar+ ions at 8 keV from polycrystaline samples have been performed, using non-resonant laser ionization and subsequent time-of-flight mass spectroscopy. Besides sputtered atoms, also dimer and trimer contributions in the order of 10−1 to 10−2 and 10−3 to 10−4, respectively, are found in the sputtered flux. The data obtained here together with previously published data by other groups for different bombarding energies provide strong support for the validity of the recombination model.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00324422
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  • 10
    Digitale Medien
    Digitale Medien
    Laser-stimulated desorption of potassium atoms (1991)
    Springer
    Applied physics 52 (1991), S. 445-447 
    Details
    ISSN: 1432-0630
    Schlagwort(e): 82.65 ; 36.40 ; 73.20
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau , Physik
    Notizen: Abstract Desorption of K atoms by laser-excitation of surface plasmons in small K particles is reported. The desorption rate has been measured for different laser wavelengths and particle sizes. Time-of-flight measurements reveal a kinetic energy of the desorbed atoms of Ekin=0.13(3) eV. From the experimental data it is concluded that the desorption mechanism is non-thermal in nature. Comparison of the results reported here with our earlier work on Na desorption is made.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00323657
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  • 11
    Digitale Medien
    Digitale Medien
    Effects of low nitrate and high sugar concentrations on anthocyanin content and composition of grape (Vitis vinifera L.) cell suspension (1991)
    Springer
    Plant cell reports 9 (1991), S. 500-504 
    Details
    ISSN: 1432-203X
    Schlagwort(e): anthocyanin ; cell culture ; nitrate ; sucrose ; Vitis vinifera
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In pigmented cells of Vitis vinifera suspension cultures, best accumulation of anthocyanins was obtained when nitrate concentration was reduced from 25 mM to 6.25 mM and when sucrose concentration was increased from 88 mM to 132 mM. Under such conditions growth was greatly decreased. However, cell viability was maintained. The increases in anthocyanins in pigmented cells were due largely to increases in peonidin — glucoside. The high sucrose and the low nitrate concentrations can be one of the important culture factors in controlling of anthocyanin production by cell cultures.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00232105
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  • 12
    Digitale Medien
    Digitale Medien
    Sequence analysis of wheat mitochondrial transcripts capped in vitro: definitive identification of transcription initiation sites (1991)
    Springer
    Current genetics 20 (1991), S. 245-251 
    Details
    ISSN: 1432-0983
    Schlagwort(e): Mitochondrion ; Transcription ; Guanylyltransferase ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary To identify transcription initiation sites in wheat mitochondria, the nascent 5′-ends of transcripts were specifically labeled by incubation of wheat mitochondrial RNA with [α-32P]GTP in the presence of the enzyme guanylyltransferase. After separation of the resulting capped transcripts by electrophoresis in polyacrylamide gels, individual RNAs were recovered and directly sequenced. Four RNA sequences obtained in this way were localized upstream of the protein-coding genes atpA, coxII, coxIII and orf25. Comparison of mRNA and gene sequences allowed precise positioning of transcription initiation sites for these four genes. Sequence similarities immediately upstream of these sites define a conserved motif that we suggest as a candidate regulatory element in wheat mtDNA. The relationship between this motif and putative mitochondrial promoters in other plant species is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00326239
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  • 13
    Digitale Medien
    Digitale Medien
    A mechanism for the loss of cytochrome P-450 in primary mouse hepatocytes (1991)
    Springer
    Molecular and cellular biochemistry 108 (1991), S. 151-156 
    Details
    ISSN: 1573-4919
    Schlagwort(e): cytochrome P-450 ; mitochondria ; heme ; hepatocytes ; mitochondrial DNA ; cell culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract This study examined various biochemical parameters such as mitochondria and mitochondrial DNA (mtDNA), total heme and cyto P450 content in fresh hepatocytes and dedifferentiated hepatocytes. These parameters were chosen in order to understand the dramatic decrease in drug metabolism in cultured hepatocytes. The data in this study shows a temporal decrease in cytochrome P450, total heme and also a decrease in mitochondria. Also, the ratio of mtDNA content to mitochondrial density was found to increase as hepatocytes underwent dedifferentiation. Stereological analysis of cell preparations provided a measure of mitochondrial density per cell area and mtDNA content was assessed by the use of a specific radiolabelled probe. This study demonstrates that a loss of the organelle which is partially responsible for synthesis of heme correlates with a decrease in cytochrome P450.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00233120
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  • 14
    Digitale Medien
    Digitale Medien
    Adrenergic hormones and control of cardiac myocyte growth (1991)
    Springer
    Molecular and cellular biochemistry 104 (1991), S. 35-43 
    Details
    ISSN: 1573-4919
    Schlagwort(e): α1-adrenergic receptors ; β-adrenergic receptors ; cardiac muscle ; cell culture ; gene expression ; protein kinase C
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract The molecular mechanisms of cardiac myocyte growth are relevant to important problems in cardiovascular disease. A cell culture model has been developed to explore the role of adrenergic hormones in cardiac myocyte growth and gene expression. Activation of a cardiac myocyte α1-adrenergic receptor by catecholamines induces hypertrophic growth of neonatal rat cardiac myocytes and initiates selective increases in contractile protein gene transcription. These effects on growth and gene expression do not depend on contractile activity. The cardiac myocytes contain at least two subtypes of α1-adrenergic receptors and at least three isoforms of protein kinase C (PKC). A distinct α1 receptor subtype may mediate hypertrophy and gene transcription. Different isoforms of PKC are translocated to different intracellular sites on activation, and there is evidence that the β-PKC isoform may be an element in the signal transduction pathway from an α1 receptor at the surface to the cardiac myocyte nucleus. Growth regulation through a β-adrenergic receptor can also be demonstrated in the culture model. The growth response mediated through a β-adrenergic receptor differs in several respects from that transduced through an al adrenergic receptor.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00229801
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  • 15
    Digitale Medien
    Digitale Medien
    Sequence analysis of a chalcone isomerase cDNA of Phaseolus vulgaris L. (1991)
    Springer
    Plant molecular biology 16 (1991), S. 167-169 
    Details
    ISSN: 1573-5028
    Schlagwort(e): Phaseolus vulgaris ; cell culture ; chalcone isomerase ; elicitor
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00017927
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  • 16
    Digitale Medien
    Digitale Medien
    Molecular cloning of a cDNA from Lupinus polyphyllus cell cultures encoding a ribosomal protein (rps16) (1991)
    Springer
    Plant molecular biology 16 (1991), S. 739-740 
    Details
    ISSN: 1573-5028
    Schlagwort(e): Lupinus polyphyllus ; cell culture ; cDNA clone ; ribosomal protein ; rps 16
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00023439
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  • 17
    Digitale Medien
    Digitale Medien
    Nucleotide sequence of the wheat chloroplast petB and petD genes encoding apocytochrome b-563 and subunit IV of the cytochrome bf complex (1991)
    Springer
    Plant molecular biology 16 (1991), S. 745-747 
    Details
    ISSN: 1573-5028
    Schlagwort(e): chloroplast genes ; cytochrome b6 ; introns ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00023441
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  • 18
    Digitale Medien
    Digitale Medien
    Nucleotide sequence of a wheat (Triticum aestivum L.) cDNA clone encoding the waxy protein (1991)
    Springer
    Plant molecular biology 16 (1991), S. 1099-1101 
    Details
    ISSN: 1573-5028
    Schlagwort(e): wheat ; Triticum aestivum ; cDNA clone ; waxy protein
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00016086
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  • 19
    Digitale Medien
    Digitale Medien
    Expression and stability of amplified genes encoding 5-enolpyruvylshikimate-3-phosphate synthase in glyphosate-tolerant tobacco cells (1991)
    Springer
    Plant molecular biology 17 (1991), S. 1127-1138 
    Details
    ISSN: 1573-5028
    Schlagwort(e): tobacco ; 5-enolpyruvylshikimate-3-phosphate synthase ; cDNA clone ; gene expression ; gene amplification ; glyphosate ; cell culture ; tolerance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Two distinct cDNAs for 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) were obtained from a glyphosate-tolerant tobacco cell line. The cDNAs were 89% identical and the predicted sequences of the mature proteins were greater than 83% identical with EPSPS proteins from other plants. Tobacco EPSPS proteins were more similar to those from tomato and petunia than Arabidopsis. One cDNA clone, EPSPS-1, represented a gene that was amplified in glyphosate-tolerant cells, while the gene for EPSPS-2 was unaltered in these cells. Consequently, EPSPS-1 mRNA was more abundant in tolerant than unselected cells, whereas EPSPS-2 mRNA was at relatively constant levels in these cell lines. Exposure of unselected cells and tobacco leaves to glyphosate produced a transient increase in EPSPS mRNA. However, glyphosate-tolerant cells containing amplified copies of EPSPS genes did not show a similar response following exposure to glyphosate. A significant proportion of the EPSPS gene amplification was maintained when tolerant cells were grown in the absence of glyphosate for eight months. Plants regenerated from these cells also contained amplified EPSPS genes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00028730
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  • 20
    Digitale Medien
    Digitale Medien
    Determination of the transmission frequency of chromosome 4S l of Aegilops sharonensis in a range of wheat genetic backgrounds (1991)
    Springer
    Theoretical and applied genetics 81 (1991), S. 519-523 
    Details
    ISSN: 1432-2242
    Schlagwort(e): Preferential transmission ; Triticum aestivum ; Aegilops sharonensis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The transmission of chromosome 4S l from Aegilops sharonensis was observed in a range of wheat genetic backgrounds. Chromosome 4S l was transmitted at a very high frequency (at least 97.8%) in all crosses. The genetic background appears to only have a small effect on transmission. The frequency of transmission of chromosome 4S l was the same in each genetic background through both the male and female gametes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219443
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  • 21
    Digitale Medien
    Digitale Medien
    Seed set after pollination with in-vitro-matured, isolated pollen of Triticum aestivum (1991)
    Springer
    Theoretical and applied genetics 81 (1991), S. 576-580 
    Details
    ISSN: 1432-2242
    Schlagwort(e): Pollen culture ; Pollen maturation ; Pollination ; Triticum aestivum ; Gliadins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Immature pollen of two varieties of Triticum aestivum, at the stage right after the first pollen mitosis, was isolated from individual anthers and cultured in microcultures of microliter droplets. In a specifically designed medium, some of the pollen grains developed to maturity. These were applied to excised stigmas on agar, where they produced pollen tubes. Application to flowers in vivo led to seed set. Pollen was matured in vitro from a variety that produced a different protein banding pattern on SDS-PAGE as compared to the variety that was pollinated. The protein banding in the produced seeds showed the hybrid pattern, demonstrating that the seeds were not produced by self-pollination in this in-breeding species but by pollination with the in-vitro-matured pollen.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00226721
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  • 22
    Digitale Medien
    Digitale Medien
    Characterization of HSP-70 cognate proteins from wheat (1991)
    Springer
    Theoretical and applied genetics 82 (1991), S. 615-620 
    Details
    ISSN: 1432-2242
    Schlagwort(e): HSP-70 ; BiP/GRP-78 ; Wheat ; Triticum aestivum ; Chaperone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Animal and plant cells contain a family of constitutively expressed HSP-70 cognate proteins that are localized in different subcellular locations and are presumed to play a role in protein folding and transport. Utilizing antibodies raised against the yeast endoplasmicreticulum-localized HSP-70 cognate termed BiP/GRP-78, as well as antibodies raised against the Escherichia coli HSP-70 protein DnaK, we have identified and characterized a large family of closely related proteins in wheat. One protein band of 78 kDa that is apparently closely related to yeast BiP was localized in the endoplasmic reticulum. This band cross-reacted with the yeast BiP but not with the DnaK-specific antibodies. The yeast BiP antibodies also recognized a cytoplasmic protein of 70 kDa that is probably related to the HSC-70 cognate proteins. These two proteins were further confirmed as HSP-70 cognates by their ability to bind to an ATP-agarose column. Probing of proteins from purified wheat mitochondrial preparations with the yeast BiP and DnaK-specific antibodies showed that this organelle contained a family of HSP-70-related proteins. The yeast BiP antibodies recognized two mitochondrial proteins of 60 and 58 kDa, but failed to detect any protein in the size rang of 70 to 80 kDa. However, the presence of immunologically distinct proteins of 90 and 78 kDa, as well as of lower molecular weight from this family in the mitochondria, was shown by probing with the DnaK-specific antibodies. A new protein of 30 kDa, cross-reacting with anti-yeast BiP antibodies, was detected only in developing seeds, close to their maturity. The evolution of HSP-70 cognate proteins in wheat as shown in this study is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00226799
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  • 23
    Digitale Medien
    Digitale Medien
    Characterization of variability and relationships among components of partial resistance to leaf rust in CIMMYT bread wheats (1991)
    Springer
    Theoretical and applied genetics 82 (1991), S. 674-680 
    Details
    ISSN: 1432-2242
    Schlagwort(e): Puccinia recondita tritici ; Triticum aestivum ; Rust resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A study of spring bread wheat (Triticum aestivum) germ plasm developed at the International Maize and Wheat Improvement Center (CIMMYT) showed highly significant phenotypic variability for each component of partial resistance (namely, uredial appearance period, latency period, uredial number and uredial size) to Puccinia recondita f. sp. tritici. All of the wheat genotypes displayed longer uredial appearance and latency periods and decreased uredial number and uredial size when compared to the susceptible check cultivar ‘Morocco’. Positive correlations between uredial appearance period and latency period, and uredial number and uredial size, and negative correlations between uredial appearance and latency periods and uredial number and uredial size, inclusive, suggested that the components of partial resistance were either tightly linked or under pleiotropic genetic control. Compared to ‘Morocco’, all entries had slow disease progress in the field and variation occurred in the germ plasm for the area under the leaf rust progress curve. Disease progress was negatively correlated with uredial appearance and latency periods, whereas a positive correlation was observed with uredial number and uredial size. Certain genotypes displayed high levels of partial resistance resulting in low disease incidence in the field.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00227310
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  • 24
    Digitale Medien
    Digitale Medien
    Hybridization between Triticum aestivum L. and Agropyron michnoi Roshev. (1991)
    Springer
    Theoretical and applied genetics 81 (1991), S. 312-316 
    Details
    ISSN: 1432-2242
    Schlagwort(e): Triticum aestivum ; Agropyron michnoi ; Intergeneric hybrid ; Chromosome pairing ; Self-fertile
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Intergeneric hybrids between Triticum aestivum cv ‘Chinese Spring’ (2n=6x=42, AABBDD) and Agropyron michnoi Roshev. (2n=4x=28, PPPP) were obtained by embryo culture. Their spike characteristics were similar to those of common wheat but, unlike their parents, they were long-awned. The average meiotic chromosome pairing at MI of F1 hybrids was: 6.39 I +3.75 rodII+8.64 ringII+0.81 III+0.30 IV+0.04 V, the bivalent and multivalent formation of which was much higher than expected from the genomic formulae. It is especially worthwhile to note that the F1 hybrids were self-fertile, self set being 0.15%, and seeds were easily obtained from the backcross of f1 plants with hexaploid and tetraploid wheats; here the seed set was more than 20.0%. The polyploid taxa and the position of A. Michnoi in Agropyron are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00228669
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  • 25
    Digitale Medien
    Digitale Medien
    Cytological analysis on the distribution and origin of the alien chromosome pair conferring blue aleurone color in several European common wheat (Triticum aestivum L.) strains (1991)
    Springer
    Theoretical and applied genetics 81 (1991), S. 551-558 
    Details
    ISSN: 1432-2242
    Schlagwort(e): Triticum aestivum ; Triticum monococcum ; blue aleurone color ; Chromosome substitution/translocation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Meiotic chromosome pairing and Giemsa C-banding analyses in crosses of several European blue-grained wheat strains with Chinese Spring double ditelosomic and other aneuploid lines showed that Triticum aestivum Blaukorn strains “Berlin,” “Probstdorf,” “Tschermak,” and “Weihenstephan” are chromosome substitutions, in which the complete wheat chromosome 4A pair is replaced, whereas the strains “Brünn” and “Moskau” are 4B substitutions. The alien chromosome pair in all of these strains is an A genome chromosome (4A) from diploid Triticum monococcum or T. boeoticum not present in common tetraploid and hexaploid cultivated wheats. The Blaukorn strain Weihenstephan “W 70a86” possesses, in addition to a rye chromosome pair 5R compensating for the loss of part of chromosome 5D, a 4A/5DL translocation replacing chromosome pair 4B of wheat.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219448
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  • 26
    Digitale Medien
    Digitale Medien
    Studies of serum-free medium for the generation of lymphokine-activated killer cells (1991)
    Springer
    Cytotechnology 6 (1991), S. 39-47 
    Details
    ISSN: 1573-0778
    Schlagwort(e): cell culture ; lymphocyte ; lymphokine-activated killer cell ; recombinant interleukin 2 ; serum-free medium
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract We examined a serum-free medium (designated as TYI 101) for the generation of lymphokine-activated killer (LAK) cells from human lymphocytes, regional lymph node lymphocytes (RLNL) and peripheral blood lymphocytes (PBL). TYI 101 medium consisted of, in addition to nutrient mixture, transferrin, insulin, fetuin, sodium selenite, 2-mercaptoethanol, o-phosphorylethanolamine, chick egg yolk and porcine kidney extract. These hormones were effective for supporting RLNL proliferation as assessed by (3H)-thymidine uptake. When human lymphocytes from two different sources were cultivated with recombinant interleukin 2 (rIL-2) in TYI 101 medium, LAK activity was generated. In cultures of PBL from a healthy donor, LAK cells were generated in TYI 101 medium as efficiently as in RPMI 1640 medium supplemented with 10% human AB-type serum (RPMI-AB). In cultures of RLNL from lung cancer patients, LAK activity obtained in TYI 101 medium was about sixty-five percent of that in RPMI-AB. However, the addition of a small amount of AB-type serum improved the generation of LAK activity, LAK cell expansion, and cell viability in TYI 101 medium. We conclude that TYI 101 medium can be used for the generation of LAK cells from human lymph node lymphocytes with supplementation of none or only a reduced amount of human serum.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00353701
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  • 27
    Digitale Medien
    Digitale Medien
    Development of a new culture system for human lymphokine-activated killer cells: Comparison with a conventional static culture method (1991)
    Springer
    Cytotechnology 7 (1991), S. 75-83 
    Details
    ISSN: 1573-0778
    Schlagwort(e): adoptive immunotherapy ; cell culture ; cell culture apparatus ; Interleukin-2 ; lymphokine-activated killer cells
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract We recently developed a new culture system based on dialysis perfusion (designated JCC-device) for the generation and expansion of human lymphokine-activated killer (LAK) cells (Murata et al., 1990). More recently we have scaled up the volume of the culture vessel of the JCC-device from 100 ml to 400 ml for clinical use. In the present study, using this new 400 ml JCC-device, we cultured human lymph node lymphocytes (LNL) obtained from 8 surgical patients with primary lung cancer, and investigated the cellular characteristics in comparison with a conventional batchwise culture system using tissue culture dishes. With the JCC-device, the cell density reached a maximum 2.7×107 cells/ml with greater than 90% viability by the appropriate exchange of perfusion medium and by making additions at the appropriate intervals for recombinant interleukin-2 (rIL-2). The expansion fold of LNL with the JCC-device, ranging 6.6- to 19.2-fold (mean 13.8-fold), was not significantly different from that in dish cultures. There was no marked difference in cell surface phenotypes between the two culture systems in 7 out of 8 cases. As for LAK activity of LNL, the JCC culture was either superior or equal in 4 out of 8 cases, but inferior in the other 4 cases to the conventional dish cultures. In the latter cases, the usage of serum for the JCC culture was limited, which might have resulted in the low LAK activity. The JCC-device was able to reduce the consumption of basal medium, rIL-2 and serum by 20%, 84% and 96%, respectively compared to the conventional tissue culture systems. The JCC-device improved the routine performance of adoptive immunotherapy with LAK cells and rIL-2.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00350913
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  • 28
    Digitale Medien
    Digitale Medien
    A new method for the encapsulation of mammalian cells (1991)
    Springer
    Cytotechnology 7 (1991), S. 121-130 
    Details
    ISSN: 1573-0778
    Schlagwort(e): cell culture ; cellulose sulphate ; encapsulation ; monoclonal antibodies ; poly-dimethyl-diallyl-ammoniumchloride
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract A new encapsulation method was developed for the cultivation of mammalian cells. The capsules were produced using a solution of sodium cellulose sulphate (CS)(1.5%) and poly-dimethyl-diallyl-ammoniumchloride (PDMDAAC). When CS droplets fell into the precipitation bath consisting of a 2% solution of PDMDAAC, immediately a membrane at the interphase was built up. The influences of varying encapsulation process parameters on capsule characteristics, cell growth, and monoclonal antibody production were tested. This new method showed advantages when compared to other methods mainly due to time simplicity of the whole process.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00350918
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  • 29
    Digitale Medien
    Digitale Medien
    Serum-free culture of carcinoma cell lines (1991)
    Springer
    Cytotechnology 5 (1991), S. 31-46 
    Details
    ISSN: 1573-0778
    Schlagwort(e): serum-free ; cell culture ; carcinoma
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00365532
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  • 30
    Digitale Medien
    Digitale Medien
    Influence of temperature on the proliferative response of rainbow trout gonadal fibroblasts to cortisol and RU 486 (1991)
    Springer
    Fish physiology and biochemistry 9 (1991), S. 261-269 
    Details
    ISSN: 1573-5168
    Schlagwort(e): Cortisol ; RU 486 ; temperature ; rainbow trout ; cell culture ; [3H]-Thymidine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The rainbow trout gonadal cell line, RTG-2, which survives temperatures from 0 to 28°C and proliferates at 5 to 26°C, responded to cortisol from 28°C to 0°C by influencing [3H]-thymidine incorporation into DNA. Over the normal temperature range of rainbow trout, 10–22°C, cortisol inhibited [3H]-thymidine incorporation. The antiglucocorticoid RU 486 had no effect on [3H]-thymidine incorporation at these temperatures and blocked the response to cortisol. Another antiglucocorticoid RU 362 also had no effect but was less effective in blocking the cortisol response. During incubation at 28°C this inhibitory response to cortisol was detected inconsistently during the first 24 h but was observed consistently during the second 24 h. At 0°C, cortisol and RU 486 had no effect during short treatments, but a 60 h exposure to either steroid stimulated [3H]-thymidine incorporation over a 48 h labelling period. These results suggest that temperature shifts between 10–22°C, do not change the direction of a response to cortisol and support the use of the upper portion (20–22°C) of the temperature range for studies on salmonid cells in culture.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02265147
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  • 31
    Digitale Medien
    Digitale Medien
    An advisory model for control of Puccinia recondita in winter wheat (1991)
    Springer
    European journal of plant pathology 97 (1991), S. 275-288 
    Details
    ISSN: 1573-8469
    Schlagwort(e): Triticum aestivum ; brown rust ; monitoring ; epidemiology ; yield loss ; disease management
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Epidemics ofPuccinia recondita and resulting yield loss of winter wheat were studied in field experiments over three seasons in the Netherlands. Results are reported and used to construct an advisory model for control of brown rust, based on rust monitoring. If the fraction of leaves with rust (I) at a certain development stage is determined, the average number of rust sori per leaf (M) was estimated by: M=EXP(1.84+1.39ln(ln[1/(1-I)]). The final number of sori per leaf (Mf) at early dough was forecast by an exponential growth: Mf=M·EXP(RGR·t). The relative growth rate (RGR) averaged 0.163/day and the forecasting period, t, until early dough, was derived from published data. The forecast number of sori-days per leaf (S, AUDPC-value) was then obtained by: S=(Mf-M)/RGR. Yield loss (kg/ha) by brown rust was 1.15 times the number of sori-days per leaf at low rust intensities. The efficacy of the fungicides used was 85%. The forecast avoidable yield loss (L, kg/ha) was calculated by: L=0.85 (1.15 S). Economic thresholds for brown rust control at different development stages are given for Dutch wheat fields at a cost level of 270 kg/ha for one fungicide application.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01974223
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  • 32
    Digitale Medien
    Digitale Medien
    Effects of high ammonium concentrations on growth and anthocyanin formation in grape (Vitis vinifera L.) cell suspension cultured in a production medium (1991)
    Springer
    Plant cell, tissue and organ culture 27 (1991), S. 169-174 
    Details
    ISSN: 1573-5044
    Schlagwort(e): ammonium ; anthocyanin ; cell culture ; growth kinetics ; production medium ; Vitis vinifera
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cultivating Vitis vinifera cell suspensions in a production medium which is characterized by high sucrose and low nitrate concentrations (132 mM and 6.25 mM respectively) repressed growth but enhanced the intracellular accumulation of anthocyanins, especially peonidin 3-glucoside. Increasing the ammonium concentration of the production medium from 2 to 8–16 mM increased growth and decreased the accumulation of anthocyanins and peonidin 3-glucoside specifically. Instead, peonidin 3-p-coumaroylglucoside accumulated. At 24 mM ammonium concentration, growth was inhibited and accumulation of peonidin 3-p-coumaroylglucoside was significant (p〈0.05) and represented 42% of total anthocyanins after 12 days of culture compared with 19% in the production medium with 2 mM ammonium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00041286
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  • 33
    Digitale Medien
    Digitale Medien
    Variation for root traits and their genetic control in spring wheat (1991)
    Springer
    Euphytica 59 (1991), S. 1-8 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; root ; combining ability ; correlation ; dry matter ; variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Wheat root characters which influence vital plant processes have scarcely been explored for their genetic control. This study was conducted to i) examine the diversity of root traits and associated shoot traits in spring wheat (Triticum aestivum L.) cultivars; ii) study the nature of genetic control of selected traits; and iii) examine associations among root and shoot traits. Three experiments were conducted in the greenhouse with plants grown in the vermiculite medium in clear plastic tubes. In the first experiment, 42 spring wheat cultivars were grown for three weeks and measurements were taken on root length, leaf length, root number, leaf number, root dry weight, and top dry weight. In the second study, 15F1's originating from a partial diallel mating of six cultivars along with the parents were evaluated for 4 weeks. The data on root length, leaf length, and root number were subjected to diallel analysis according to Griffing's method 4, fixed model. A third experiment consisted of studying 2 F2 populations with 141 plants per population. In the first study the 42 cultivars exhibited a wide range of variation for all six traits. Diallel analysis revealed significant effects of both general combining ability (GCA) and specific combining ability (SCA) for root length, leaf length, and root number. Parents with high GCA estimates were identified. Significant positive correlation coefficients were found among root and shoot traits. Analysis of F2's for root length indicated quantitative nature of inheritance of root length.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00025355
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  • 34
    Digitale Medien
    Digitale Medien
    Classification of landraces and improved cultivars of hexaploid wheats (Triticum aestivum, T. compactum and T. spelta) grown in the USA and described in 1922 (1991)
    Springer
    Euphytica 59 (1991), S. 33-47 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; bread wheat ; Triticum compactum ; club wheat ; Triticum spelta ; spelt wheat ; classification ; genetic diversity ; landraces ; cultivars ; USA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary In 1922 Clark, Martin and Ball published descriptions of 207 hexaploid wheat landraces and improved cultivars, collected in the USA: 189 bread wheat accessions (Triticum aestivum), 24 club wheats (T. compactum) and four spelt wheats (T. spelta). After omitting 24 bread wheat accessions with identical descriptions as other accessions, the descriptions were used here to classify the remaining 183 accessions into five clusters on the basis of 10 selected characters. Clusters 1 and 3 include mainly accessions introduced from North and West Europe. These accessions must derive from the European Zeeuwse and Gelderse landrace groups. Hence most of the accessions belonging to these two clusters belong to the North and West European heritage. Cluster 2 includes most of the accesions introduced from Australia and Canada, or belonging to the club wheats. Most accessions from the USSR1 are included in cluster 4. Here we also find Turkey and related landraces. All but one pubescent accessions are included in cluster 5. The wide variation of US wheats, described in 1922, forms the basis of the Foundation Germplasm wheats as defined by Cox (1991). Apparently no hard white winter wheat landraces and cultivars were described.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00025359
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  • 35
    Digitale Medien
    Digitale Medien
    Hybridization barriers between wheat and rye: In vitro pollen assays and electrophoretic survey (1991)
    Springer
    Euphytica 52 (1991), S. 147-153 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Secale cereale ; rye ; hybridization ; pollen-tube-growth ; wide-crosses
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Five- to seven-day-old ovaries from Triticum aestivum vars Hope (non-crossable), Chinese Spring (CS, crossable) and the chromosomal substitution line Chinese Spring/Hope 5B (CS/H5B) were used to test the hypothesis that an ovarian substance inhibits rye (Secale cereale var Wrens) pollen tube growth. In vitro assays on a semi-solid medium demonstrated that a soluble, dialyzed lysate from Hope or CS/H5B ovaries inhibited rye pollen tube elongation significantly more than a similar lysate from CS ovaries (26%, 13% and 5% respectively compared to controls). When only the 20 longest tubes from each sample were included in the analysis the relationship was maintained (33%, 22% and 15% for Hope, CS/H5B and CS respectively). Heating the Hope lysate at 100° C for 10 min reduced the inhibition from 26% to 14% for all pollen tubes measured (n = 51 per sample) and from 33% to 20% when only the 20 longest pollen tubes per sample were analyzed. Isoelectric focusing followed by sodium dodecyl sulfate polyacrylamide electrophoresis (IEF/SDS-PAGE) and non-equilibrium pH gradient electrophoresis (NEPHGE) revealed several differences in the polypeptide profiles of soluble lysates from vars Hope, CS and CS/H5B. While two striking differences were observed, a 50 kilodalton (kD) polypeptide with an isoelectric point (pI) of approximately 8.5 and 100 kD polypeptide (pI∼4) from CS lysates which were considerably reduced in lysates of Hope and CS/H5B, none were obviously associated with the Hope 5B chromosome and therefore cross-incompatibility.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00029390
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  • 36
    Digitale Medien
    Digitale Medien
    The introduction into bread wheat of a major gene for resistance to powdery mildew from wild emmer wheat (1991)
    Springer
    Euphytica 53 (1991), S. 57-60 
    Details
    ISSN: 1573-5060
    Schlagwort(e): bread wheat ; Erysiphe graminis ; powdery mildew ; Triticum aestivum ; Triticum dicoccoides ; wild emmer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary A new source of resistance to wheat powdery mildew caused by Erysiphe graminis has been transferred to hexaploid bread wheat, Triticum aestivum, from the wild tetraploid wheat, Triticum dicoccoides. The donor was crossed to bread wheat and the pentaploid progeny was then self-pollinated. Plants having a near stable hexaploid chromosome complement were selected in the F3 progeny and topcrossing and backcrossing of these to a second wheat cultivar to improve the phenotype was undertaken. Monosomic analysis of early backcross lines showed the transferred gene to be located on chromosome 4A. The gene has been designated Pm16.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00032033
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  • 37
    Digitale Medien
    Digitale Medien
    Crossability of some bread wheat landraces and improved cultivars from western Himalayas with rye (1991)
    Springer
    Euphytica 53 (1991), S. 137-141 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Secale cereale ; rye ; crossability ; Himalayas
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Crossability of 62 bread wheat accessions (14 landraces from Himachal Pradesh and 48 others) was examined with rye. The 3 rye cultivars did not differ in their relative crossability with 4 of the wheat accessions studied. On the other hand, the wheat cultivars differed greatly among themselves in their crossability with rye. Most of the wheat cultivars showed poor (〈10%) crossability. Two of the 14 landraces from Himachal Pradesh were found to be free from the crossability inhibitors as they showed very high (〉50%) crossability, whereas none of the other 48 cultivars studied was so.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00023794
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  • 38
    Digitale Medien
    Digitale Medien
    Induction of a mutation in the male fertility gene of the preferentially transmitted Aegilops sharonensis chromosome 4S1 and its application for hybrid wheat production (1991)
    Springer
    Euphytica 54 (1991), S. 33-39 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; Aegilops sharonensis ; male sterility ; preferential transmission ; hybrid wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Wheat plants nullisomic for chromosome 4B are male sterile due to the absence of the male fertility gene Ms1. However, plants in which chromosome 4B has been substituted by the preferentially transmitted chromosome 4S1 of Ae. sharonensis are male fertile due to the compensating effect of Ms4 on the alien chromosome. This substitution line has been mutated and three recessive mutation of Ms4 have been selected. Plants homozygous for these mutations are male sterile. The implication of these mutations for hybrid wheat production is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00145628
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  • 39
    Digitale Medien
    Digitale Medien
    Major gene control of tolerance of bread wheat (Triticum aestivum L.) to high concentrations of soil boron (1991)
    Springer
    Euphytica 55 (1991), S. 217-228 
    Details
    ISSN: 1573-5060
    Schlagwort(e): boron ; inheritance ; tolerance ; Triticum aestivum ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The genetic control of tolerance of wheat to high concentrations of soil boron was studied for five genotypes. Each genotype represented one of five categories of response to high levels of boron, ranging from very sensitive to tolerant. Tolerance to boron was expressed as a partially dominant character, although the response of an F1 hybrid, relative to the parents, varied with the level of boron applied. The F1 hybrids responded similarly to the more tolerant parent at low B treatments and intermediate to the parents at higher treatments. Ratios consistent with monogenic segregation were observed for the F2 and F3 generations for the combinations (WI*MMC) × Kenya Farmer, Warigal × (WI*MMC) and Halberd × Warigal. The three genes, Bo1, Bo2 and Bo3, while transgressive segregation between two tolerant genotypes, G61450 and Halberd, suggested a fourth locus controlling tolerance to boron.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00021242
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  • 40
    Digitale Medien
    Digitale Medien
    Pedigree analysis of the origin of manganese tolerance in Canadian spring wheat (Triticum aestivum L.) cultivars (1991)
    Springer
    Euphytica 56 (1991), S. 107-120 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Canada ; genotypic differences ; manganese toxicity ; manganese tolerance ; origin ; pedigree ; screening ; Triticum aestivum ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Breeding wheat (Triticum aestivum L.) for tolerance to manganese (Mn) might be in some cases more feasible and economical than use of soil amendments. As part of research on the heritability of Mn tolerance, a study on the level of Mn tolerance in Canadian wheat cultivars and its probable origin was accomplished by analysis of cultivar pedigrees and drawing phylogenetic maps to discern filial relationships. Cultivar tolerance to Mn was determined by relative root weight (RRW) in solution culture in the presence of 500 μM Mn. A total of 91 cultivars were screened, 76 of which were Canadian. These data, together with data from another 28 cultivars reported in the literature, were used to draw two pedigree maps, a map for Canadian cultivars only, and a map for the Mn-tolerant Canadian cultivars Norquay and Laura. Results indicated a range of tolerance to Mn among Canadian cultivars. Manganese tolerance, found in either Canadian or foreign germplasm, and of either recent or older selection or origin, seems to have originated from land races from Rio Grande do Sul, the southernmost state of Brazil. Tolerance may have been introduced into Canadian germplasm directly by the use of Brazilian cultivars as parents, or indirectly by the introduction of Mexican germplasm with Brazilian parentages. This information will help the plant breeder to develop plant breeding systems, and may also help in the study of the mechanisms for Mn tolerance in wheat.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00042053
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  • 41
    Digitale Medien
    Digitale Medien
    Greenhouse evaluation of red winter wheats for resistance to the Russian wheat aphid (Diuraphis noxia, Mordvilko) (1991)
    Springer
    Euphytica 57 (1991), S. 221-225 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Diuraphis noxia ; Russian wheat aphid ; host plant resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The Russian wheat aphid (Diuraphis noxia, Mordvilko) (RWA) is responsible for significant economic damage to cereal crops in arid and semi-arid environments. In this research 20 red winter wheats originating from Iran were evaluated for resistance to RWA. Leaf rolling, leaf folding, and leaf chlorosis were measured using 0 to 3 scales. An overall mean damage score was calculated as the average of the three measured damage symptoms. Plants from seven central Asian accessions (PI222666, PI222668, PI225226, PI225267, PI225271, PI243630, and PI243642) had mean damage scores significantly lower (p 〈 0.001) than ‘Stephens’ wheat (RWA susceptible) and not significantly different from ‘Border’ oat (RWA resistant). These results are consistent with previous studies which found a high frequency of resistant wheats collected from the central Asian region.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00039668
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  • 42
    Digitale Medien
    Digitale Medien
    Breeding for hard red winter wheat cultivars adapted to conventional-till and no-till systems in northern latitudes (1991)
    Springer
    Euphytica 58 (1991), S. 57-63 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; cold hardiness ; cultivar x tillage interaction ; tillage
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Conservation tillage in the Great Plains of North America has increased in recent years, in part, to control soil erosion, increase soil water storage and reduce production costs. No-till production is recommended for winter wheat (Triticum aestivum L.) in northern latitudes for the purpose of trapping snow and protecting the crop from freezing temperatures. A 5 year field study was conducted at four North Dakota locations from 1984–85 through 1988–89 to determine if significant cultivar x tillage interactions existed for grain yield of winter wheat. Fourteen hard red winter wheat cultivars were planted in both conventional-till and no-till systems. Significant cultivar x tillage interactions were obtained for grain yield from both a weighted analysis across all environments and from individual analyses of 12 of the 16 environments in which wheat survived under both tillage systems (P〈0.05). Regression of cultivar yield on mean environment yield produced b values that varied little between conventional till and no-till for 10 of the 14 cultivars. The top five yielding cultivars were the same for both tillage systems and had b values 〉 1.0. Although the cultivar x tillage interaction may be a result of differential winter survival rather than tillage per se, this study suggests that selection for winter wheats with superior yield performance can be conducted under either no-till or conventional-till systems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00035340
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  • 43
    Digitale Medien
    Digitale Medien
    Genes for resistance to stripe rust in four spring wheat varieties (1991)
    Springer
    Euphytica 58 (1991), S. 171-181 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Puccinia striiformis ; yellow rust ; stripe rust ; host plant resistance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Four spring wheat (Triticum aestivum L.) varieties differing in origin and reaction in the seedling stage to pathotype CDL-6 (extant in California) were intercrossed and examined in greenhouse conditions in F1, F2, and F3 generations. Digenic and transgressive segregation was found in all crosses. The four varieties each had infection types (1 immune, 9 susceptible) and putative resistance genes as follows: ‘Anza’, IT 7, YrA; ‘Glennson 81’, IT 2, Yr9; ‘Yecora Rojo’, IT 6, YrC; and ‘Ollanta’, IT 4–6, YrL. ‘Anza’ was classified as susceptible, ‘Yecora Rojo’ and ‘Ollanta’ as intermediate in seedling resistance, and ‘Glennson 81’ as resistant in the seedling stage.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00022818
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  • 44
    Digitale Medien
    Digitale Medien
    In vitro culture variation of wheat and rye caused by genes affecting plant growth habit in vivo (1991)
    Springer
    Euphytica 61 (1991), S. 233-240 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Secale cereale ; rye ; day-length insensitivity ; semi-dwarfness ; tissue culture response
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The influence of genes affecting the ‘plant growth habit’ in wheat (Rht8 and Ppd1) and rye (ct1 and ct2) on tissue culture response was studied using immature embryos. Whereas the semi-dwarfing gene Rht8 seems to promote only a minor effect, the day-length sensitive allele ppd1 determined a major increase in callus growth and regeneration ability. With regards to their tissue culture efficiency, the four alleles studied could be ranked as follows: ppd1〉Rht8〉rht8〉Ppd1. In contrast to wheat, the GA insensitive semi-dwarfing genes of rye (ct1 and ct2) appear not to influence in vitro response.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00039663
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  • 45
    Digitale Medien
    Digitale Medien
    Silicon accumulation and water uptake by wheat (1991)
    Springer
    Plant and soil 137 (1991), S. 191-199 
    Details
    ISSN: 1573-5036
    Schlagwort(e): durixerollic calciorthid soil ; evapotranspiration ; plant water relations ; silicon transport soil ; temperature ; Triticum aestivum ; uptake ; water balance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Silicon (Si) content in cereal plants and soil-Si solubility may be used to estimate transpiration, assuming passive Si uptake. The hypothesis for passive-Si uptake by the transpiration stream was tested in wheat (Triticum aestivum cv. Stephens) grown on the irrigated Portneuf silt loam soil (Durixerollic calciorthid) near Twin Falls, Idaho. Treatments consisted of 5 levels of plant-available soil water ranging from 244 to 776 mm provided primarily by a line-source sprinkler irrigation system. Evapotranspiration was determined by the water-balance method and water uptake was calculated from evapotranspiration, shading, and duration of wet-surface soil. Water extraction occurred from the 0 to 150-cm zone in which equilibrium Si solubility (20°C) was 15 mg Si L−1 in the Ap and Bk (0–58 cm depth) and 23 mg Si L−1 in the Bkq (58–165 cm depth). At plant maturity, total Si uptake ranged from 10 to 32 g m−2, above-ground dry matter from 1200 to 2100 g m−2 and transpiration from 227 to 546 kg m−2. Silicon uptake was correlated with transpiration (Siup=−07+06T, r2=0.85) and dry matter yield with evapotranspiration (Y=119+303ET, r2=0.96). Actual Si uptake was 2.4 to 4.7 times that accounted for by passive uptake, supporting designation of wheat as a Si accumulator. The ratio of Si uptake to water uptake increased with soil moisture. The confirmation of active Si uptake precludes using Si uptake to estimate water use by wheat.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00011197
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  • 46
    Digitale Medien
    Digitale Medien
    Ferric chelate reduction by suspension culture cells and roots of soybean: A kinetic comparison (1991)
    Springer
    Plant and soil 130 (1991), S. 75-80 
    Details
    ISSN: 1573-5036
    Schlagwort(e): cell culture ; FeHEDTA ; Glycine max ; iron chelate reduction ; iron nutrition ; soybean
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The abilities of suspension cultures and intact roots of soybean (Glycine max L. cv. Hawkeye) to reduce ferric chelate were compared. Ferric chelate was supplied as ferric hydroxyethylethylenediaminetriacetic acid (FeHEDTA) and reduction was measured spectrophotometrically using bathophenan-throlinedisulfonic acid (BPDS) as the ferrous scavenger. Ferric chelate reduction by cell suspension cultures showed typical saturation kinetics; however, no difference was observed between cells that had been continuously grown with Fe (+Fe) and those that had been grown for four days without added Fe (−Fe). Values for Km and Vmax, determined from a Lineweaver-Burk plot, were 57 μM and nmoles mg-1 dry weight for the +Fe cells and 50 μM and 22 nmoles mg-1 dry weight for the -Fe cells, respectively. Ferric chelate reduction by Fe-deficient roots also exhibited saturation kinetics, while roots grown with adequate Fe did not reduce ferric chelate. The Km and Vmax values for Fe-deficient roots were 45 μM and 20 nmoles mg-1 dry weight, respectively, and did not differ from values obtained for cells in culture. This study offers strong evidence that the mechanism responsible for the reduction of ferric chelate is the same for cultured cells and roots and that the process is controlled at the cellular level. We propose that suspension cultures can be used as an alternative to intact roots in the study of ferric chelate reduction.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00011858
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  • 47
    Digitale Medien
    Digitale Medien
    Effect of phosphorus supply to the surface roots of wheat on root extension and rhizosphere chemistry in an acidic subsoil (1991)
    Springer
    Plant and soil 134 (1991), S. 73-82 
    Details
    ISSN: 1573-5036
    Schlagwort(e): aluminium tolerance ; cation-anion balance ; phosphate translocation ; split-root ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Seedlings of two cultivars of wheat (Triticum aestivum L.) differing in tolerance to aluminium (Al) were grown using a split-root sand/soil culture technique. Each culture tube was divided horizontally into a surface (0–150 mm) compartment and a subsurface (150–250 mm) compartment separated by a root-permeable paraffin wax barrier. Thus phosphorus (P) supplied to surface roots could not percolate or diffuse into the soil in the subsurface compartment. The soil in the subsurface compartment was divided into ‘rhizosphere’ and ‘non-rhizosphere’ zones using a porous (5 μm) membrane. Root growth of both cultivars into the subsurface zone was enhanced by increased P supply to surface roots, but did not conform to known relationships between root growth and soil pH, extractable-Al, or pH, Al or P concentrations in soil solution. Concentrations of Al in soil solution in the rhizosphere were greater than those in solution in the bulk soil. Concentrations of Al reactive with pyrocatechol violet (30s-RRAI) in the rhizosphere soil solution were generally greater than those in non-rhizosphere soil. With the Al-sensitive cultivar, root dry weight and length increased as concentrations of RRAl in the rhizosphere soil solution increased. Increased concentrations of Al in rhizosphere soil solutions were not related to the presence of organic ligands in solution. The effect of P in promoting root penetration into the acidic subsurface stratum was not related to differential attainment of maturity by the plant shoots, but appeared to be related to the effect of P in enhancing the rate of root growth. Thus, suboptimal supply of P to the surface roots of a plant, even at levels sufficient to preclude development of nutritional (P) stress symptoms, may seriously reduce tolerance to Al, and hence diminish the ability of roots to penetrate into acidic subsoils.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00010719
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  • 48
    Digitale Medien
    Digitale Medien
    Biological activity and chemical isolation of root saponins of six cultivars of alfalfa (Medicago sativa L.) (1991)
    Springer
    Plant and soil 135 (1991), S. 83-94 
    Details
    ISSN: 1573-5036
    Schlagwort(e): aglycone ; allelopathy ; arabinose ; bioassay ; Bromus secalinus ; dormancy rating ; Medicago sativa ; saponins ; thin-layer chromatography (TLC) ; Trichoderma viride ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Wheat, cheat and Trichoderma viride bioassays were used to establish the relationship between the content of biologically active saponins in the roots and the degree of winter dormancy and/or time of six cultivars of alfalfa over the period January to August, 1988. Wheat and cheat bioassay results indicated no significant difforences among cultivars, whereas T. viride was inhibited most by extracts of roots collected during months with high rainfall and rapid growth. Cheast seedling roots were inhibited 8–10% more than those of wheat seedling roots indicating that alfalfa root saponins were more effective as allelopathic compounds in preventing growth of cheat than that of wheat alone. An average of 14 different saponins per cultivar were separated by thin-layer chromatograms. Saponins, and the aglycones produced by acid hydrolysis of the May samples, were separated by thin-layer chromatography. The conclusion is that the amount, structure, and type of saponins present in alfalfa roots vary with time.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00014781
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  • 49
    Digitale Medien
    Digitale Medien
    Promotion of growth of wheat seedlings by a sterile red fungus in relation to plant density and soil fertility (1991)
    Springer
    Plant and soil 135 (1991), S. 306-308 
    Details
    ISSN: 1573-5036
    Schlagwort(e): growth promotion ; sterile red fungus ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Enhancement of shoot and root growth of wheat seedlings by a sterile red fungus was evident even when sufficient nutrients were supplied and density of plants per pot was increased (from 15 to 30 plants per pot of 400 g soil). It is likely that production of hormonal-type substances by these fungi may be involved in the phenomenon observed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00010922
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  • 50
    Digitale Medien
    Digitale Medien
    Distribution of magnesium in wheat (Triticum aestivum L.) in relation to supply (1991)
    Springer
    Plant and soil 136 (1991), S. 183-193 
    Details
    ISSN: 1573-5036
    Schlagwort(e): diagnosis ; distribution ; magnesium deficiency ; Triticum aestivum ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The aims of this study were to describe the distribution of magnesium (Mg) and its retranslocation within wheat, in order to develop diagnostic procedures for Mg deficiency. Plants were grown in solution culture with both constant supply (0, 5, 10, 20, 40, 80, 160 μMMg) and discontinued supply (40 μM and 160 μM decreased to nil). Magnesium was depleted from old leaves when Mg supply to the roots was halted. However, initial deficiency symptoms occurred on young leaves under constant but inadequate supply, contrasting with previous reports. Magnesium concentrations were also lower in young leaves compared to old leaves. Symptoms of yellowing and necrosis occurred if the leaf tissue contained 〈1194 μgg−1, irrespective of leaf age. The minimum Mg concentration in whole shoots associated with maximum shoot weight was 932 μgg−1; for the youngest emerged blade (YEB) it was 861 μgg−1. Symptoms were apparent on the young leaf before a reduction in shoot weight was measurable. The concentration of Mg in the YEB and whole shoot were better related to solution Mg concentration than was the Mg concentration in the old leaf.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02150049
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  • 51
    Digitale Medien
    Digitale Medien
    Mass selection of wheat for grain filling without transient photosynthesis (1991)
    Springer
    Euphytica 54 (1991), S. 111-116 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; drought resistance ; yield ; selection ; grain filling ; kernel
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Post-anthesis chemical desiccation of wheat (Triticum aestivum L.) plants in the field eliminates transtent photosynthesis by killing all green tissues, thus revealing the plant's capacity for grain filling from stored stem reserves, as the case is for post-anthesis stress such as drought or leaf diseases. This study was conducted to investigate whether mass selection for large kernels under chemical desiccation would lead to the improve ment of grain filling in the absence of transient photosynthesis. Six crosses of common spring wheat were subjected to three cycles of mass selection from F2 through F1 when selection was performed for large kernels by sieving grains from plants that were erther chemically desiccated after anthesis, or not (controls). The resulting 36 bulks (six crosses by three selection cycles by two selection environments) were compared with their respective F2 base populations, when tested with and without chemical desiccation. Selection for large kernels under potential conditions (without chemical desiccation) did not improve kernel weight under potnetial conditions, evidently because these materials were lacking in genetic variation for kernel weight under potential conditions. In four of the crosses, 3rd cycle selection for large kernels under potential conditions decreased kernel weight under chemical desiccation. On the other hand, selection for large kernels under chemical desiccation was effective in improving kernel weight and test weight under chemical desiccation, depending on the cross and the selection cycle, with no genetic shift in mean days to heading or mean plant height. Selection for large kernels under chemical desiccation was also effective in some cases in increasing kernel weight under potential conditions. The results are interpreted to show that selection under potential conditions and under chemical desiccation operate on two different sources for grain filling, namely transient photosynthesis and stem reserve utilization, respectively. In order to expose genetic variability for stem reserve utilization to selection pressure, transient photosynthesis must be eliminated, as done by chemical desiccation in this study.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00145637
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  • 52
    Digitale Medien
    Digitale Medien
    Gliadin allele composition of Yugoslav winter wheat cultivars (1991)
    Springer
    Euphytica 54 (1991), S. 285-295 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; gliadins ; APAGE ; multiple allelism ; variation ; Yugoslavia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The complete gliadin allele composition of 57 Yugoslav common winter wheat cultivars was studied. Large differences were found in gliadin genotypes among cultivars bred at different Yugoslav breeding centres as well as between early and recent wheats bred in the Novi Sad breeding centre. Yugoslav wheats have limited variation in gliadin alleles, of which Gli-A1a, Gli-B1b, Gli-B1l, Gli-D1b, Gli-A2e, Gli-B2b, Gli-D2a are shown to be the most frequent. Examples of favoured alleles to new cultivars are described. 40% of the studied wheat cultivars have natural biotypes differing in gliadin allele composition. The frequency of cultivars with the biotypes differs greatly among breeding centres.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00023005
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  • 53
    Digitale Medien
    Digitale Medien
    Comparison of resistance of triticale, wheat and spelt to septoria nodorum blotch at the seedling and adult plant stages (1991)
    Springer
    Euphytica 55 (1991), S. 43-48 
    Details
    ISSN: 1573-5060
    Schlagwort(e): adult plant resistance ; seedling resistance ; Septoria nodorum ; septoria nodorum blotch ; X Triticosecale ; triticale ; Triticum aestivum ; wheat ; T. spelta ; spelt
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary On average, the cereal species studied were susceptible to septoria nodorum blotch (SNB), except for spring triticale on leaf and head and winter titicale on leaf, that appeared to be significantly more resistant, than the other ones. In all three species the SNB response of the adult plants was to a limited extent only predicted by the reaction on first leaf seedlings. In most cases it was impossible to predict the response to SNB of adult plants on the basis of seedling reaction. Correlations between the adult plant stage and the seedling stage, or detached seedling leaves, appears not to be sufficient for use in practical breeding work. A reversal of reaction to SNB was even found between the above growth stages in studied spring and winter wheat varieties.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00022558
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  • 54
    Digitale Medien
    Digitale Medien
    Combining ability analysis for harvest index in winter wheat (1991)
    Springer
    Euphytica 55 (1991), S. 229-234 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; harvest index ; diallel analysis ; genotypic and phenotypic correlations ; assimilate partitioning
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Cereal breeders have used harvest index (HI) as a selection criterion in segregating generations to identify physiologically superior lines with improved partitioning of total assimilate into grain. Information on combining ability for HI of the hard red winter wheat (Triticum aestivum L.) cultivars of the Southern Great Plains is not available. A study was undertaken to examine HI of seven genetically diverse winter wheat parents, evaluate their general combining ability (GCA) and specific combining ability (SCA) effects, and study correlations of HI with several agronomic traits. The seven parents were crossed in a half-diallel mating design to produce 21 crosses. The F1's, their F2 progenies, and the parents were evaluated in replicated field tests at Stillwater and at Lahoma, OK. The combining ability analysis was performed using Griffing's Method 4, Model 1. The results showed significant variation among parents for HI. The GCA and the SCA effects were mostly inconsistent between generations and between environments. However, parents with consistently high HI and positive GCA estimates were identified. The progeny with high HI mostly resulted from parents with high GCA estimates. The correlations between HI and agronomic traits indicated that improvement in HI should also result in high grain yield, early maturity, and short plant height.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00021243
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  • 55
    Digitale Medien
    Digitale Medien
    Additive and epistatic effects of allelic variation at the high molecular weight glutenin subunit loci in determining the bread-making quality of breeding lines of wheat (1991)
    Springer
    Euphytica 55 (1991), S. 277-285 
    Details
    ISSN: 1573-5060
    Schlagwort(e): HMW glutenin subunits ; bread-making quality ; Triticum aestivum ; wheat ; epistasis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The relation has been studied between the high molecular weight glutenin (HMWg) subunit alleles and the bread-making quality of 226 lines of winter wheat (T. aestivum L.), grown in The Netherlands. The lines represented a wide range of genetic backgrounds, and had not been selected for quality, in contrast to the established varieties used by other authors. The variation in HMWg subunit genotypes accounted for about 20% of the total variation in loaf volume among the lines. Most important was the allelic variation at the Glu-D1 locus. The Glu-D1 allele encoding the subunits 5+10 was superior to its allelic counterpart, encoding 2+12. The difference in average of loaf volume between groups of lines containing 5+10 or 2+12 was negatively related with protein content of the flours. When protein content was below 9.2%, no effect of allelic variation at the Glu-D1 locus was present. Epistatic effects between the Glu-I loci also contributed to the variation in loaf volume of the lines: i.e. the effect of allelic variation at Glu-A1 and Glu-B1 depended on the allele present at the Glu-D1. The contribution of the epistatic effects was about half the contribution of the additive effects, and should therefore be included in predictive models for bread-making quality.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00021248
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  • 56
    Digitale Medien
    Digitale Medien
    Measurement of response to vernalization in Australian wheats with winter habit (1991)
    Springer
    Euphytica 57 (1991), S. 9-17 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; winter wheat ; intrinsic earliness ; photoperiod ; vernalization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Development in wheat is strongly controlled by sensitivity to vernalization and photoperiod, and to a lesser degree by non-vernalizing temperature and intrinsic earliness. A method to measure effect of vernalization in wheats with winter habit is described. Twenty seven wheats with winter habit and eight with spring/facultative habit were studied, comprising breeding lines and cultivars with maturities suited to south-central New South Wales. Effect of vernalization on the development of these wheats was quantified by integrating responses to vernalizing treatments of differing duration. Intrinsic earliness was measured as time for vernalized seedlings to grow to ear emergece in an 18h photoperiod with day/night temperature of 21/16°C, and response to photoperiod as the difference in time to ear emergence between 9 and 18h daylengths. Integrated response to vernalization is sensitive to both cumulative and thresh-hold responses and is applicable to wheats of all habit type. Integrated response to vernalization and intrinsic earliness were positively associated within wheats with winter habit. Wheats were largely of restricted origin, so that there were few allelic differences at Vrn loci to disrupt this association, which suggests intrinsic earliness may modify response to vernalization. Though integrated response to vernalization was measured with artificial treatments, it was strongly associated with ear emergence for wheats with winter habit when grown at a site in New South Wales.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00040473
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  • 57
    Digitale Medien
    Digitale Medien
    Genes for leaf rust resistance in Indian and Pakistani wheats tested with Mexican pathotypes of Puccinia recondita f.sp. tritici (1991)
    Springer
    Euphytica 57 (1991), S. 27-36 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Puccinia recondita tritici ; leaf rust ; rust resistance ; slow rusting
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Genes conferring low seedling reaction to Mexican pathotypes of Puccinia recondita f. sp. tritici in 71 bread wheat (Triticum aestivum L.) cultivars from India and Pakistan were postulated. In total, 9 known and one unknown genes were identified, either singly or in combination: Lr1 (in 20 cultivars), Lr3 (5), Lr10 (21), Lr11 (1), Lr13 (43), Lr17 (5), Lr23 (14), Lr26 (2), Lr27 + Lr31 (2), and the unknown gene in 2 cultivars. Additional temperature-sensitive seedling resistance appeared to occur in 27 cultivars. This resistance in at least 15 cultivars appeared to be due to Lr34. Area under the disease progress curve (AUDPC) for these 27 cultivars indicated variable levels of adult plant resistance. Several other cultivars with high seedling infection types to one or more of the predominant field pathotypes were also partially resistant in the field. High levels of adult plant resistance occurred in some cultivars even in the absence of known seedling resistance genes with major effects.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00040475
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  • 58
    Digitale Medien
    Digitale Medien
    Influence of race and post infection temperature on two components of partial resistance to wheat leaf rust in seedlings of wheat (1991)
    Springer
    Euphytica 58 (1991), S. 13-20 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Adult plant resistance ; infection frequency ; latency period ; partial resistance ; Puccinia recondita f.sp. tritici ; race-specificity ; temperature sensitivity ; Triticum aestivum ; wheat ; wheat leaf rust
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Components of partial resistance, infection frequency and latency period, were determined in 71 winter and spring wheat genotypes in the seedling stage, after infection with three races of leaf rust (‘Felix 3B’, ‘Clement B’ and ‘Betuwe 85C’) at three different day/night temperature regimes (24/18°C, 18/12°C and 12/6°C). The genotypes were split into two groups and two separate experiments were carried out. Five genotypes, SVP 84039, Akabozu, Banco, BH 1146 and Orso, conferred a low infection frequency and a long latency period and Westphal 12A a long latency period, indicating a relatively high level of partial resistance. The correlation coefficient between infection frequency and latency period was low. Race-specificity was not found. There was a significant temperature effect on the latency period. In the second experiment the temperature x genotype interaction was significant. Temperature-response functions of transformed data demonstrated that the latency periods of four relatively resistant genotypes, Westphal 12A, Banco, BH 1146 and Orso and of Sarno and Mirela were most sensitive to temperature. The range between the genotypes with the longest and the shortest latency period was highest at 12°C. Therefore, low temperature regimes are preferred to distinguish differences in level of partial resistance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00035335
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  • 59
    Digitale Medien
    Digitale Medien
    An investigation of the relationship between the F1 potential and the measures of genetic distance among wheat lines (1991)
    Springer
    Euphytica 58 (1991), S. 165-170 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; choice of parents ; distance analysis ; standardized potence ; character selection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Three groups of characters selected using three methods were used to calculate genetic distance among two groups of winter wheat lines using Euclidean distance based on principal components. These wheat lines were then clustered by the unweighted pair-group arithmetic average method. The relationship between genetic distance and standardized potence was seemingly influenced by genetic materials. In order to obtain promising crosses, it is advisable to select parents from intercluster rather than intracluster materials. The results suggested that the repeatability method was better than the conventional and weighting methods for selecting characters for distance analysis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00022817
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  • 60
    Digitale Medien
    Digitale Medien
    Actual, potential and speculative applications of seaweed cellular biotechnology: some specific comments on Gelidium (1991)
    Springer
    Hydrobiologia 221 (1991), S. 181-194 
    Details
    ISSN: 1573-5117
    Schlagwort(e): callus ; cell culture ; domestication ; protoplast ; tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cellular biotechnology is a promising application in the propagation and selection of superior strains of seaweeds. Although axenic cultures, organogenetic tissue cultures, vegetative micro-propagation, callus induction and high yields of agar from calli have been described for several species of Gelidium, a number of basic problems remain to be solved. These include standardized methods for obtaining axenic cultures, identification of requirements for organic nutrients, PGR's, cellular disorganization and reorganization, somaclonal variation and somatic incompatibilities. Future progress in seaweed biotechnology will depend on the resolution of many of these problems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00028374
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  • 61
    Digitale Medien
    Digitale Medien
    Experiments with culture media for planarian cells (1991)
    Springer
    Hydrobiologia 227 (1991), S. 187-192 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Turbellaria ; planaria ; cell culture ; leucine uptake
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have tested various conditions for the culture of cells dispersed from planarians. The cells were procurred by digestion of planarian tissue in pronase and filtering through a nylon mesh. Using incorporation of L-[3H]leucine into protein as a gauge of cell growth, we found that the optimum salt concentration was about 50% of that for mammalian cells (about 160 mOsm) and that optimum pH was about 8. Sera from several species and a tetrapeptide (Arg-Gly-Asp-Ser, the cell-attachment sequence in fibronectin) greatly increased leucine uptake and extended cell survival up to a period of about two weeks. Various growth factors and some other substances tested had no effect on uptake of leucine, cell morphology, or survival. A few other compounds tested were cytotoxic. None of the experimental media promoted cell proliferation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00027601
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  • 62
    Digitale Medien
    Digitale Medien
    Study of a factor produced by suspension-cultured Pinus radiata cells which enhances cell growth at low inoculum densities (1991)
    Springer
    Plant cell, tissue and organ culture 26 (1991), S. 53-59 
    Details
    ISSN: 1573-5044
    Schlagwort(e): cell culture ; cell wall ; conditioned medium ; inoculum density ; low inoculum growth factor ; Pinus radiata
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Pinus radiata cells in suspension culture abruptly lose their growth capacity when diluted below a critical inoculum density. This threshold density can be lowered by adding the supernatant (conditioned medium) from healthy cultures which have been grown separately at high densities. Fresh medium is conditioned rapidly indicating that the factor responsible is either potent or produced rapidly. Activity-response curves increase progressively with concentration indicating that still greater effect may be obtained if the factor can be concentrated following separation from other medium components. The effect is not mimicked by a number of candidate compounds (including auxins, cytokinins, polyamines and vitamins). Partial characterisation studies indicate that the factor is relatively small (〈1 000 dalton) and possibly an oligosaccharide. It is considered that the factor is an essential structural component of the walls of expanding cells where it is reversibly-bound.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00116610
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  • 63
    Digitale Medien
    Digitale Medien
    Response of different wheat tissues to increasing doses of ethyl methanesulfonate (1991)
    Springer
    Plant cell, tissue and organ culture 26 (1991), S. 141-146 
    Details
    ISSN: 1573-5044
    Schlagwort(e): calluses mutagenesis ; embryo mutagenesis ; EMS somatic effect ; immature ; embryo mutagenesis ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Mutation experiments require careful selection of a mutagen with characteristics suited to the tissue source and mutagenesis objective, and an appropriate treatment regime. The objectives of the present investigation were:-to compare the ability of immature embryos to initiate calluses and calluses derived from immature embryos to survive and grow after being treated with ethyl methanesulfonate (EMS) doses of 0.2, 0.4, 0.8, 1.2, and 1.6% (v/v) and-to compare these results with those published for seed mutagenesis. To determine if the response of tissue source to EMS treatment varied with genotype, tissues from two spring wheat cultivars, ‘Angus’ and ‘Pavon 76’, were used. The combined analysis of variance detected highly significant differences (p≤0.01) among doses. The higher the dose, the lower the tissue survival in each tissue source. No significant differences were detected between cultivars, tissue sources, in the cultivar by dose interaction, tissue source by dose interaction, tissue source by cultivar interaction, or tissue source by cultivar by dose interaction. Hence, both cultivars and tissue sources responded similarly to EMS doses. The predicted LD20 are 0.35%±0.08% for the immature embryo treatment, and 0.36%±0.10% for the callus treatment. The predicted LD50 are 0.82%±0.13% for the immature embryo treatment, and 0.77%±0.13% for the callus treatment. These results were very similar to published results for seed mutagenesis, hence seed mutagenesis research may be applicable to immature embryo and callus mutagenesis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00039935
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  • 64
    Digitale Medien
    Digitale Medien
    Two types of asymmetric acetylcholinesterase in chick hindlimb muscle: Developmental profiles,in Vivo and in cell culture, and recovery after inactivation (1991)
    Springer
    Cellular and molecular neurobiology 11 (1991), S. 191-201 
    Details
    ISSN: 1573-6830
    Schlagwort(e): acetylcholinesterase ; asymmetric-form types ; chick hindlimb muscle ; development ; cell culture ; diisopropylfluorophosphate inactivation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary 1. We have analyzed the behavior of two types of asymmetric molecular forms (A forms) of acetylcholinesterase (AChE) during development of chick hindlimb muscle,in vivo and in cell culture, and upon irreversible inactivation of peroneal muscle AChE with diisopropylfluorophosphate (DFP)in vivo. 2. In agreement with previous developmental studies on chick muscle, globular forms of AChE (G forms) are predominant in chick hindlimb at early embryonic ages, being gradually replaced by A forms as hatching (and, therefore, onset of locomotion) approaches. Of the two A-form types, AI appears and accumulates significantly earlier than AII, so that A/G and II/I ratios higher than 1 are attained only at about hatching time. 3. Cultures prepared from 11-day chick embryo hindlimb myoblasts express both types of A forms, with a combined activity of 27% of total AChE after 12 days in culture. AI forms appear again earlier and are much more abundant than type II asymmetric species through the life span of cultures. 4. All AChE activity in the peroneal muscle is irreversibly inactivated by injection of DFPin vivo. The recovery of A forms follows the same sequence described for normal development, with a delayed and slower recovery of AII forms as compared with AI. 5. Several hypotheses involving tail polypeptides or tissue target molecules, or posttranslational interconversion, are proposed to help explain the earlier appearance and accumulation of AI forms in chick muscle.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00712809
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  • 65
    Digitale Medien
    Digitale Medien
    Accumulation of peonidin 3-glucoside enhanced by osmotic stress in grape (Vitis vinifera L.) cell suspension (1991)
    Springer
    Plant cell, tissue and organ culture 24 (1991), S. 49-54 
    Details
    ISSN: 1573-5044
    Schlagwort(e): anthocyanin ; cell culture ; osmotic potential ; reverse-phase HPLC ; Vitis vinifera
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cell cultures of grapes, Vitis vinifera L. cv Gamay Fréaux were grown under different conditions of external osmotic potential induced by an increase of sucrose concentration or by the addition of mannitol to the culture medium. Addition of 82 mM mannitol or increasing sucrose concentration to 132 mM had similar effects on repressing growth. Cyanidin 3-glucoside, peonidin 3-glucoside and peonidin 3-p-coumaroylglucoside are three main anthocyanins of Vitis cells. Increasing osmotic potential from −0.43 MPa to −0.8 MPa in the medium resulted in a significant intracellular accumulation of anthocyanin especially peonidin 3-glucoside in the pigmented cells. High osmotic potential appears to stimulate the methylation of anthocyanins. Osmotic potential is an important culture factor and may be useful in the controlling of anthocyanin production and composition.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00044265
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  • 66
    Digitale Medien
    Digitale Medien
    Increased anthraquinone production in Galium vernum cell cultures induced by polymeric adsorbents (1991)
    Springer
    Plant cell, tissue and organ culture 24 (1991), S. 207-210 
    Details
    ISSN: 1573-5044
    Schlagwort(e): anthraquinone production ; cell culture ; Galium vernum ; polymeric adsorbents ; secretion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Anthraquinones produced by suspension cultures of Galium vernum are completely retained intracellularly. Surprisingly, in the presence of some polymeric adsorbents anthraquinones are partially released into the culture medium. The secretion and in situ removal stimulates anthraquinone production in cell cultures of Galium vernum. Best results were obtained with Wofatit ES and Amberlite XAD-2.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00033478
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  • 67
    Digitale Medien
    Digitale Medien
    Wheat anther culture: effect of genotype and environmental conditions (1991)
    Springer
    Plant cell, tissue and organ culture 24 (1991), S. 233-236 
    Details
    ISSN: 1573-5044
    Schlagwort(e): anther culture ; cultivars ; Triticum aestivum ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Twenty-two cultivars and lines of winter and spring wheat (Triticum aestivum L.) were studied, most for the first time, for their anther culture response. The response was genotype dependent. Plants grown in the field gave higher callus induction frequency than those grown in the greenhouse and the controlled environment chamber. Donor plants grown in a season of low drought stress as compared to a season of severe drought stress resulted in a higher frequency of callus induction. Spherical microcalli were observed in two wheat genotypes in some of only those anthers that were placed with only one loculus in contact with the medium. Wheat lines that were more responsive to anther culture were identified.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00033482
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  • 68
    Digitale Medien
    Digitale Medien
    Isolation and characterization of Daucus carota L. cell lines resistant to 2-deoxy-D-glucose (1991)
    Springer
    Plant cell, tissue and organ culture 25 (1991), S. 147-152 
    Details
    ISSN: 1573-5044
    Schlagwort(e): cell culture ; Daucus carota ; 2-deoxy-D-glucose ; invertase ; selection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Variant carrot (Daucus carota L.) cell lines resistant to the growth inhibitory effects of the glucose analogue 2-deoxy-D-glucose (dGlc) were isolated utilizing a feeder plate technique. Growth of sensitive cells was less than 7.5% of controls on medium supplemented with 3.0 mM dGlc, whereas resistant variants achieved growth ranging from 15% to 70% of that in controls. Increased levels of acid invertase activity in variant cell lines in response to dGlc in the culture medium, together with decreased sensitivity of the acid invertase enzyme (EC 3.2.1.26) to dGlc, is proposed as one of several potential mechanisms contributing to the observed dGlc resistance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00042186
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  • 69
    Digitale Medien
    Digitale Medien
    Morphologic identification of epithelial cell types of the human tracheo-bronchus in cell culture (1991)
    Springer
    Methods in cell science 13 (1991), S. 5-11 
    Details
    ISSN: 1573-0603
    Schlagwort(e): bronchial epithelium ; cell culture ; intermediate filaments ; carbohydrate cytochemistry ; lectins ; peroxidase-labeled lectins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A protocol is presented for correlating the morphology of human bronchial epithelial cells after Papanicolaou staining with their periodic acid schiff (PAS)/AB-reactivity, intermediate filament type, and the pattern of staining with lectins having specific affinities for glycoconjugates:griffionia simplicifolia (GSA-IB4; terminal alpha-d-galactose),Dolichos biflorus (DBA,N-acetyl-d-galactosamine). The combination of these stains identified differentiation markers in morphologic studies of normal, transformed, and malignant bronchial epithelial cells in culture.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02388197
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  • 70
    Digitale Medien
    Digitale Medien
    Use of the pH-sensitive dye BCECF to study pH regulation in cultured human kidney proximal tubule cells (1991)
    Springer
    Methods in cell science 13 (1991), S. 205-209 
    Details
    ISSN: 1573-0603
    Schlagwort(e): pH ; NH 4 + ; BCECF ; human kidney ; proximal tubule ; cell culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary This protocol describes the use of the pH-sensitive, intracellularly trapped dye 2′,7′-bis (2-carboxyethyl), 5 (and -6) carboxyfluorescein (BCECF), to characterize the pH regulating mechanisms in cultured human kidney proximal tubule cells. This is a reliable method for intracellular pH measurements and is applicable to single cells, cell suspensions, and confluent cultures.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02388128
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  • 71
    Digitale Medien
    Digitale Medien
    A direct fluorimetric DNA assay on cell suspensions (1991)
    Springer
    Methods in cell science 13 (1991), S. 285-288 
    Details
    ISSN: 1573-0603
    Schlagwort(e): DNA ; fluorimetry ; fibroblast ; cell culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary An improved direct fluorimetric assay is described using bisbenzimidazol fluorescence at 356 nm excitation and 458 nm emission wavelengths. The turbidity of the medium was shown to have no effect on fluorescence under an absorbance of 0.2 at the excitation wavelength. The method was evaluated by comparisons with a colorimetric DNA assay and cell counting. The linearity of fluorescence was determined up to 15μg/ml of DNA. The method was very reproducible and sensitive to detect 10 ng/ml of DNA and may be used for cell suspensions containing around 5000 cells/ml or more.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02388262
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  • 72
    Digitale Medien
    Digitale Medien
    Fetal bovine oviduct epithelial cell monolayers: Method of culture and identification (1991)
    Springer
    Methods in cell science 13 (1991), S. 289-294 
    Details
    ISSN: 1573-0603
    Schlagwort(e): fetal bovine ; oviduct ; cell culture ; microscopy ; immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Bovine epithelial cell monolayers were obtained for culture from fetal oviduct after in situ trypsinization. Isolated ciliated and secretory cells obtained in high yield with good viability were suspended in B2-MENEZO'S medium supplemented with 7.5% fetal bovine serum FBS. The plated primary cultures reached confluency 2 days after initial seeding, producing a monolayer of cohesive polygonal cells with viability of 85 to 95%. Associated with this large epithelial cell population, ciliated cells as well as a few elongated spindle cells were observed. After the first subculture the ciliated cells disappeared and the epithelial cells in the monolayer grew more rapidly to confluence than adult-derived cultures. In addition, frozen-thawed oviduct epithelial cells also maintained a level of 75 to 85% viability during postthaw subculture. The epithelial cells maintained their secretory activity in culture as indicated by electron microscopy and immunocytochemistry. The cell culture monolayers contained keratin, a specific cytoskeletal component of epithelial cells. This culture system may offer benefits for in vitro culture of mammalian embryos.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02388263
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  • 73
    Digitale Medien
    Digitale Medien
    Characterization of stem rust resistant derivatives of wheat cultivar Amigo (1991)
    Springer
    Euphytica 58 (1991), S. 245-252 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Introgression ; leaf rust ; Puccinia spp. ; rust resistance ; species-specific probes ; stem rust ; Triticum aestivum ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Originally developed for resistance to greenbug derived from Insave rye, Amigo wheat carries two genes for resistance to stem rust. One of these genes is associated with a rye chromosome 1RS segment carrying the Sec-1 protein marker and presumably greenbug resistance. The second gene which is genetically linked to leaf rust resistance is associated with an Agropyron-derived segment. Rust tests in Canada confirmed that these genes were Sr24 and Lr24. In contrast to Agent and certain 3D/Ag derivatives from Dr. E.R. Sears, the Amigo source of Sr24/Lr24 freely recombined with white seed colour during backcrossing.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00025256
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  • 74
    Digitale Medien
    Digitale Medien
    In vitro techniques for selecting wheat (Triticum aestivum L.) for Fusarium-resistance. I. Double-layer culture technique (1991)
    Springer
    Euphytica 57 (1991), S. 251-257 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Fusarium resistance ; Fusarium spp. ; wheat ; Triticum aestivum ; double-layer technique ; in vitro selection ; somaclonal variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Calluses of spring and winter wheats (Triticum aestivum L.) were selected for Fusarium resistance in vitro, using the double-layer culture technique. Potato-dextrose agar medium in vials was inoculated with mycelia of Fusarium graminearum and F. culmorum. After one week, fungal cells were killed by autoclaving and the agar medium containing the thermostable toxic metabolites was overlayered with MS callus-growing medium. Later, wheat calluses were placed on the upper medium for 4–5 weeks, and from the surviving calluses plants were regenerated. R2 seedling populations from self-fertilized R1 plants of 4 varieties were tested for Fusarium resistance by artificial infections in the greenhouse, and 3% of the regenerated R2 plants have been found to be more resistant than the original cultivars.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00039671
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  • 75
    Digitale Medien
    Digitale Medien
    Changes in physiological attributes of the dry matter economy of bread wheat (Triticum aestivum) through genetic improvement of grain yield potential at different regions of the world (1991)
    Springer
    Euphytica 58 (1991), S. 37-49 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Biomass ; grain yield ; grain yield components ; harvest index ; Triticum aestivum ; wheat breeding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The understanding of the changes produced by plant breeding on wheat grain yield and on its determinants, through the study of the behaviour of cultivars released at different times during the breeding process, could be a useful tool to define future selection criteria. The aim of this paper was to examine the genetic improvement effects on bread wheat grain yield potential and on its major physiological determinants in different countries. Generally, it seems that the genetic improvement produced important increases in harvest index, but it did not produce important changes in total biomass. The genetic gain in grain yield ranged from 0.58 g m-2 year-1 (India) to 5.84 g m-2 year-1 (Mexico); reflecting important differences among genetic improvement programmes. However, when the comparisons were made in relative values, the difference was much lower, ranging from 0.16% year-1 to 0.90% year-1, for the previously mentioned countries, respectively. Most of the regions showed relative genetic gains of around 0.45% year-1. Similar patterns of relative genetic gains in harvest index were found. Half of the total gain in grain yield in the past was due to genetic gain in grain yield potential. However, it is expected for the future, that further increases in grain yield will rely more on genetic gain than on technologic gain. Thus, a discussion about possible strategies in future breeding programmes of bread wheat is attempted throughout the paper. The changes in grain yield were mostly associated with changes in number of grains per m2 rather than with changes in individual grain weight. It appears that the source: sink ratio during the grain-filling period was very high in old cultivars, whereas the source: sink ratio in modern cultivars is more balanced. Further increases in number of grains m-2 could be compensated by a reduction in individual grain weight, if simultaneous improvement in source strength during grain-filling is not achieved. The crop attributes which have been changed together with the mentioned traits are discussed and alternative selection criteria are suggested.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00035338
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  • 76
    Digitale Medien
    Digitale Medien
    Production and cytogenetic analysis of the intergeneric hybrids between nine Elymus species and common wheat (Triticum aestivum L.) (1991)
    Springer
    Euphytica 58 (1991), S. 81-95 
    Details
    ISSN: 1573-5060
    Schlagwort(e): Elymus species ; genome ; germplasm resources ; intergeneric hybridization ; meiosis ; Triticum aestivum ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Intergeneric hybridizations were performed between Triticum aestivum L. (2n=6x=42, AABBDD) and twelve Elymus species, ten tetraploids (2n=4x=28, SSYY) and two hexaploids (2n=6x=42, SSHHYY and SSYY??), namely, E. pendulinus (Nevski) Tzvelev, E. altissimus (Keng), Löve, E. anthosachnoides (Keng) Löve, E. brevipes (Keng) Löve, E. dolichatherus (Keng) Löve, E. parviglumis (Keng) Löve, E. pseudonutans (Keng) Löve, E. tibeticus (Melderis) G. Singh, E. semicostatus (Nees ex Steud.) Melderis, E. caucasicus (C. Koch) Tzvelev (tetraploids), and E. tsukushiensis Honda and E. tschimganicus (Drobov) Tzvelev (hexaploids). The hybrid seed sets in different combinations varied from 4.8%–72.2%, and embryo yields ranged from 3.2%–36.7%. Nine combinations produced adult hybrid plants, eight pentaploids and one hexaploid, through embryo rescue. The production of hybrid plants varied from 1.2%–30%. Chromosome pairing was analysed at metaphase I in the parental species and the hybrids. Average meiotic configurations of 33.51 I+0.74 II+0.03 III+0.001 IV were observed amongst the pentaploid hybrids although there was a large variation, and 31.42 I+5.21 II+0.04 III was recorded in the hexaploid hybrid. It is concluded from the study that: 1) very little pairing occurred between the ABD genomes in T. aestivum and the different genomes in the tetraploid Elymus species. even though the pairing behaviour varied in different combinations; 2) the hexaploid combination had distinctly higher chromosome pairing than the other pentaploid combinations, which could be due either to a low degree of homoeology between the T. aestivum and E. tschimganicus genomes or that the latter species contains, certain gene(s) which increase the meiotic pairing between genomes from the same parental species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00035343
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  • 77
    Digitale Medien
    Digitale Medien
    Effects of foliar applied benzyladenine on grain yield and grain protein in wheat (Triticum aestivum L.) (1991)
    Springer
    Plant growth regulation 10 (1991), S. 197-204 
    Details
    ISSN: 1573-5087
    Schlagwort(e): Benzyladenine (BA) ; urea ; grain protein ; yield components ; Triticum aestivum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effects of foliar applications of nitrogen and benzyladenine (BA) on grain yield and grain protein of wheat grown under field conditions were studied over 2 years with 5 cultivars at 2 locations. Nitrogen (N) at 20 kg.ha−1, and BA at 100 or 800 mg.l−1 were applied alone or combined at pre and post-anthesis; applications of BA at 8 mg.l−1 were also made on individual ears in order to study the effect on cell number. Weekly determinations of the chlorophyll content of the flag leaf were conducted after anthesis to study leaf senescence. At harvest, yield, yield components and grain protein percentage were determined. N and BA applications delayed chlorophyll loss in the flag leaf, but modified neither yield nor yield components. Foliarly applied BA increased grain protein in four of the five cultivars tested. It is concluded that delay of the senescence induced by BA might allow more energy to be available for N uptake by the crop leading to an increase in grain protein.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00024410
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  • 78
    Digitale Medien
    Digitale Medien
    The effect of polyamines on protein kinase activities of wheat (Triticum aestivum) L. anthers (1991)
    Springer
    Plant growth regulation 10 (1991), S. 363-375 
    Details
    ISSN: 1573-5087
    Schlagwort(e): Triticum aestivum ; polyamines ; protein kinases
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Protein kinase activities were extracted from anther tissue of wheat (Triticum aestivum L. cv. Zaragoza) and characterized with regard to the effects of polyamines, second messengers and plant growth hormones. The protein kinases were inhibited by polyamines and cyclic nucleotides, but were stimulated by the addition of auxins, gibberellic acid and kinetin. The dominant polyamine-sensitive kinase activity was partially purified and characterized. The optimal pH of the reaction was 7.5 to 8.0 and casein was the preferred exogenous substrate. Polyamines were inhibiting in the decreasing order of putrecine 〉 spermidine 〉 spermine. The results are discussed against the context of the anther culture technique.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00024595
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  • 79
    Digitale Medien
    Digitale Medien
    A method for estimating oxygen availability of stationary plant cell cultures in liquid media (1991)
    Springer
    Plant cell, tissue and organ culture 26 (1991), S. 195-201 
    Details
    ISSN: 1573-5044
    Schlagwort(e): Brassica napus ; cell culture ; diffusion ; liquid medium ; oxygen availability ; protoplast culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A method for estimating the oxygen availability in plant cell cultures grown in stationary liquid media (e.g. many protoplast cultures) was developed. The method is based on short-term measurements of respiration rate versus oxygen concentration on a sample of cells, suspended in liquid media. From such data it is possible to estimate the oxygen concentration at the bottom of a stagnant liquid culture, by calculating the amount of oxygen reaching the cells by diffusion. As an example, rape (Brassica napus L. cv. Omega) hypocotyl protoplasts were grown with different oxygen concentrations at the site of the cells, obtained by varying the cell density, the height of the liquid layer and the oxygen content of the gas phase. The number of surviving calli was positively correlated with the estimated oxygen availability in the range between 60 and 350 μM O2, below 60 μM all cells died. This indicates that oxygen availability can be a limiting factor in the range usually encountered in protoplast cultures, and that the method can be useful when designing optimal growth conditions for stationary cultures of plant cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00039944
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  • 80
    Digitale Medien
    Digitale Medien
    l-Phenylalanine ammonia-lyase in suspension culture cells of spruce (Picea abies) (1991)
    Springer
    Plant cell, tissue and organ culture 27 (1991), S. 267-274 
    Details
    ISSN: 1573-5044
    Schlagwort(e): cell culture ; enzyme induction ; fungal elicitor ; l-phenylalanine ammonia-lyase ; Picea abies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The activity of l-phenylalanine ammonia-lyase (PAL) (EC 4.3.1.5) was determined in seedlings, callus cells, cell suspension cultures and in young needles of spruce (Picea abies) (L.) (Karst). PAL activity increased up to 10 fold in response to transferring suspension cultured cells into new cultivation medium. PAL was also induced about 10 fold when callus cells were transferrd into liquid medium. The increase was transient and it required the presence of a carbohydrate. In cell suspension cultures, grown in the dark (white cells), but not in light-grown cultures (green cells), PAL activity was induced up to 30 fold by UV-light. With a cell wall preparation of Rhizosphaera kalkhoffii, a forest pathogenic fungus, used as elicitor, the activity of PAL could be induced more than 10 fold. The degree of induction depended on the elicitor concentration. Induction was prevented by cycloheximide but not by actinomycin D.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00157590
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  • 81
    Digitale Medien
    Digitale Medien
    Proteoglycan synthesis in cultures of murine retinal neurons and photoreceptors (1991)
    Springer
    Cellular and molecular neurobiology 11 (1991), S. 579-591 
    Details
    ISSN: 1573-6830
    Schlagwort(e): proteoglycans ; glycosaminoglycans ; mouse retina ; photoreceptors ; retinal neurons ; cell culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary 1. In recent years, a number of histochemical and immunocytochemical studies have suggested that proteoglycans, particularly those in the inter-photoreceptor matrix, exhibit altered distributions in several murine models for retinal degenerations. We are using a cell culture system to characterize the proteoglycans synthesized by neurons and photoreceptors derived from mouse retina, with the long-term goal of analyzing their role in retinal degenerations. 2. In this study we describe initial studies using cells derived from the retinas of normal mice. Cultures of retinal neurons and photoreceptors, which were free of glial, epithelia, or endothelial cells, were labeled with3H-glucosamine and35SO4. Proteoglycans isolated from the medium and cell layer were analyzed on the basis of charge, relative hydrodynamic size, and glycosaminoglycan content. 3. The studies indicate that the cultures actively synthesize proteoglycans. The medium contained predominantly chondroitin sulfate/dermatan sulfate, while the cell layer had a higher proportion of heparan sulfate, indicating a differential distribution between the two compartments.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00741447
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  • 82
    Digitale Medien
    Digitale Medien
    Studies of Sb and Bi cluster produced by laser desorption (1991)
    Springer
    The European physical journal 19 (1991), S. 203-206 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 36.40 ; 79.20
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Direct production of cations and anions of metal clusters of Sb and Bi by laser evaporation in a vacuum has been studied. Bulk sample substrates are irradiated by 1064, 532 and 355 nm beams at variable intensity, and the ions produced are accelerated and identified by time-of-flight mass spectrometry. At 1064 nm, the cation distributions show that Sb 3 + and Bi 3 + are the most abundant species, while the monomer and dimer cations are almost non-existent. The anion spectra indicate very low yields of Sb− and Bi− with dominant dimer anion species. These patterns persist with laser power variation within the stable operation domain. With lower incident laser wavelength, the mass distributions are modified, favouring the production of the light cluster ions. In no circumstances were Sb and Bi ions withn〉5 observed. Many of the observed phenomena can be explained if one assumes that for these elements, clusters withn〈6 are formed on the substrate surface. Cluster ions are produced via a prompt desorption process, and are subjected to photon induced reactions due to the same incident laser beam. However, more detailed investigation of the desorption properties will be necessary to confirm such a desorption mechanism.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01448292
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  • 83
    Digitale Medien
    Digitale Medien
    STM observation of Au fine-particles on graphite (1991)
    Springer
    The European physical journal 19 (1991), S. 333-335 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 36.40 ; 61.16.D ; 82.65.F
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Gold particles deposited on graphite in vacuum have been studied by STM observation in air. Liquid-like coalescence between small gold-particles has been observed near room temperature. Preparation of small particles in vacuum is discussed. Small particles are formed in nucleation process if the degree of coalescence of particles is reduced. Over 400 Au particles of 5 nm in diameters with a narrow size-distribution with FWHM 2 nm and a high density of 3×1012/cm2 is prepared by evaporating gold in a vacuum of about 2×10−5 Torr and at the substrate (HOPG) temperature of 20°C.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01448323
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  • 84
    Digitale Medien
    Digitale Medien
    Adsorption — desorption kinetics on epitaxially oriented palladium clusters (1991)
    Springer
    The European physical journal 19 (1991), S. 347-351 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 82.65.Jv ; 36.40
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Palladium clusters with a low size dispersion and a single crystallographic shape have been obtained by epitaxial growth on (100) MgO. The isothermal adsorption — desorption kinetics of CO is obtained by a molecular beam method allowing the direct determination of the global adsorption probability and of the mean life time of CO molecules on the clusters. Three main results are deduced from these measurements: — an increase of the adsorption rate of CO on the clusters by the capture of CO molecules physisorbed on the substrate, — a faster desorption rate from (100) than from (111) facets at high coverage, — an increase of the adsorption energy for clusters smaller than 3 nm.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01448326
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  • 85
    Digitale Medien
    Digitale Medien
    Structural stability and energetics of C, Si, and Ge microclusters: empirical many-body potential energy function calculation (1991)
    Springer
    The European physical journal 19 (1991), S. 423-425 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 36.40
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The structural stability and energetics of carbon, silicon, and germanium microclusters containing 3−7 atoms have been investigated by using a recently developed empirical many-body potential energy function (PEF), which comprises two- and three-body atomic interactions. The PEF satisfies both bulk cohesive energy per atom and bulk stability exactly. It has been found that the most stable C3−4 microclusters are linear withD ∞h symmetry but C5−7 microclusters are planar withD nh symmetry. Silicon and germanium microclusters show similar structural stability. TheX n (X=Si, Ge;n=3−7) microclusters are found to be most stable in the following forms:X 3 is triangular withD 3h symmetry,X 4 is tetragonal withT d symmetry,X 5 is square pyramidal withD 4h symmetry,X 6 is bipyramidal square withO h symmetry, and finallyX 7 is square pyramidal having two atoms underneath withD 2h symmetry.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01448343
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  • 86
    Digitale Medien
    Digitale Medien
    C n carbon clusters (n=4−6, 60, 70): interesting cases of computation/observation comparisons (1991)
    Springer
    The European physical journal 19 (1991), S. 431-433 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 35.20 ; 36.40 ; 82.30Q
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Recent theoretical studies proved some of the small carbon clusters C n (n≈1−10) are represented by several isomeric structures. Evaluation of the isomer relative stabilities is necessary for comparison of theoretical data with observation, this being exemplified by the C4 and C6 cases. For the former cluster a new energy estimation has been suggested based on the isomerism reasoning. Relative-stability evaluation for clusters of different dimensions is discussed on the C60/C70 system, pointing out a strong pressure-dependency of the picture. The scheme is matched to the recent observations of Bethune and Meijer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01448345
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  • 87
    Digitale Medien
    Digitale Medien
    On the shell structure and geometry of monovalent metal clusters (1991)
    Springer
    The European physical journal 21 (1991), S. 271-279 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 36.40
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The Hückel model is used to study the electronic structure of monovalent metal clusters. In an fcc cluster the Hückel model gives an estimate to the electronic structure of a free electron cluster. It is shown that the surface faceting of the fcc cluster can destroy the electronic shell structure already when the cluster has about 100 electrons. In the Hückel model the icosahedral structure has smaller total energy than the fcc structures, from which the Wulff construction has the smallest energy already when the cluster has 600 atoms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01426385
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  • 88
    Digitale Medien
    Digitale Medien
    The structure of deposited metal clusters generated by laser evaporation (1991)
    Springer
    The European physical journal 21 (1991), S. 285-288 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 36.40 ; 35.20
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Metal clusters have been produced using a laser evaporation source. A Nd-YAG laser beam focused onto a solid silver rod was used to evaporate the material, which was then cooled to form clusters with the help of a pulsed high pressure He beam. TOF mass spectra of these clusters reveal a strong occurrence of small and medium sized clusters (n〈100). Clusters were also deposited onto grid supported thin layers of carbon-films which were investigated by transmission electron microscopy. Very high resolution pictures of these grids were used to analyze the size distribution and the structure of the deposited clusters. The diffraction pattern caused by crystalline structure of the clusters reveals 3-and 5-fold symmetries as well asfcc bulk structure. This can be explained in terms of icosahedron and cuboctahedron type clusters deposited on the surface of the carbon layer. There is strong evidence that part of these cluster geometries had already been formed before the depostion process. The non-linear dependence of the cluster size and the cluster density on the generating conditions is discussed. Therefore the samples were observed in HREM in the stable DEEKO 100 microscope of the Fritz-Haber-Institut operating at 100 KV with the spherical aberrationc S =0.5 mm. The quality of the pictures was improved by using the conditions of minimum phase contrast hollow cone illumination. This procedure led to a minimum of phase contrast artefacts. Among the well-crystallized particles were a great amount of five- and three-fold symmetries, icosahedra and cuboctahedra respectively. The largest clusters with five- and three-fold symmetries have been found with diameters of 7 nm; the smallest particles displaying the same undistorted symmetries were of about 2 mm. Even smaller ones with strong distortions could be observed although their classification is difficult. The quality of the images was improved by applying Fourier filtering techniques.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01426387
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  • 89
    Digitale Medien
    Digitale Medien
    Neutral mass-selected lead cluster beams (1991)
    Springer
    The European physical journal 19 (1991), S. 199-201 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 36.40
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Neutral lead cluster beams with ultra-narrow size distribution were produced by neutralization of mass-selected lead cluster ions, Pb n + withn≤12, in sodium vapor under near-resonant conditions. Absolute charge exchange cross sections were measured as a function of cluster size and are on the order of 40 Å2 forn≥4. Possible fragmentation of the clusters associated with charge transfer was examined by translational spectroscopy. No indication of fragmentation was found.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01448291
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  • 90
    Digitale Medien
    Digitale Medien
    Thermionic emission from giant fullerenes (1991)
    Springer
    The European physical journal 19 (1991), S. 409-412 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 36.40
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Large even-numbered carbon clusters in the size range from 100 to 600 atoms (giant fullerenes) were generated by laser vaporization and directly injected as positive ions via a supersonic beam into the magnetic trap of an ion cyclotron resonance apparatus. Intense laser excitation of the magnetically levitated fullerenes at 4.0 eV was found to result in production of multiply charged fragments in the trap. Details of the time scale and size dependence of this process suggest it is due to thermionic emission from the superheated gas phase clusters.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01448340
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  • 91
    Digitale Medien
    Digitale Medien
    Electronic transitions in C60 and its ions (1991)
    Springer
    The European physical journal 19 (1991), S. 435-438 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 36.40
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The electronic spectrum of C60 is calculated using quantum mechanical methods. The first allowed transition in C60 is calculated at an energy of 3.5 eV and with an oscillator strength of 0.09. Several transitions are found at higher energies with comparatively strong oscillator strengths, the strongest one being at 5.78 eV (λ=214 nm). The calculated energy level diagram of C60 is also used to predict wavelengths for transitions in C 60 + and C 60 − . A comparison is made with some recently observed diffuse interstellar bands at 1180 nm and 1320 nm, which have been speculated to originate from C 60 + .
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01448346
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  • 92
    Digitale Medien
    Digitale Medien
    Internal excitation effects in the photodissociation of size selected ethylene and methanol dimers (1991)
    Springer
    The European physical journal 18 (1991), S. 181-188 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 36.40 ; 82.50.F
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The infrared photodissociation spectra of C2H4 and CH3OH dimers are measured for different internal excitation energies ΔE. The dimers are size-selected in a scattering process with He and the internal energy is varied by using (1) different collision energies, (2) different scattering angles and (3) by measuring the complete energy loss spectra with and without laser radiation by time-of-flight analysis of the scattered clusters. For (CH3OH)2 the width Γ of the spectrum increases strongly with ΔE, while the cross section at the maximum is constant, a normal behaviour for an inhomogeneously broadened system. For (C2H4)2 Γ is nearly constant after a sort of threshold and the cross section increases with increasing ΔE. These results are explained by hot band excitation and the coupling to the darkv 10-mode.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01437445
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  • 93
    Digitale Medien
    Digitale Medien
    Sub-doppler-spectroscopy of Na3 (1991)
    Springer
    The European physical journal 18 (1991), S. 257-265 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 33.20 ; 35.20 ; 36.40
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Rotationally cold Na3-molecules are formed during the adiabatic expansion of an argon beam, seeded with 5% sodium vapor. With a single mode tunable dyelaser crossing the molecular beam perpendicularly within the ion source of a mass spectrometer the Na3-molecules are excited into levels of the2 A 2-state which are then ionized by acw argon-laser. Rotational lines of the electronic2 A 2 ←X 2 B 2 transition and their hyperfine structure could be resolved using an OODR-technique. A preliminary analysis of the measured spectra is discussed and a comparison of the experimental results with ab initio calculations is presented.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01437080
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  • 94
    Digitale Medien
    Digitale Medien
    Calculation of photoionization cross sections of Na2–8 and K2–8 clusters (1991)
    Springer
    The European physical journal 18 (1991), S. 267-280 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 36.40 ; 33.80E
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Analysis of free metal clusters studied with photoionization mass spectrometry or photoelectron spectroscopy requires theoretical predictions of the photoionization cross sections to gain a deeper physical understanding. Calculated energy-dependent photoionization cross sections of Na2–8 and K2–8 clusters are presented in this study. The ground state electronic structure of the clusters are calculated using the Local Spin Density method (LSD) which is also the starting point for the cross section calculation with the continuum multiple scattering method. A basic analysis of the photoionization process is given within the independent electron picture. Strong resonances are predicted in the UV cross sections (5–10 eV) of K3–8 but not for Na3–8, interpreted as shape resonances, i.e. quasibound states in which electrons are trapped by a potential barrier. Unfortunately experimental data are only known close to the ionization threshold and a comparison between our values and experimental data in a broad energy range is not possible.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01437081
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  • 95
    Digitale Medien
    Digitale Medien
    Computer simulations of small semiconductor and metal clusters (1991)
    Springer
    The European physical journal 19 (1991), S. 31-36 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 36.40
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A brief survey is presented of recent simulations of small clusters, made with both ab-initio and classical approaches, with particular emphasis on the application of the Car-Parrinello method. The discussion mainly focusses on the structural properties of a variety of materials and on the effects of temperature.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01448249
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  • 96
    Digitale Medien
    Digitale Medien
    The influence of shells, electron thermodynamics, and evaporation on the abundance spectra of large sodium metal clusters (1991)
    Springer
    The European physical journal 19 (1991), S. 47-50 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 36.40 ; 35.20.Wg ; 03.65.-w
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Measurements of the mass abundance spectra of sodium clusters containing up to 600 atoms are presented. The clusters are produced in a seeded supersonic expansion of Ar or Kr gas, and the spectra are obtained by a time-of-flight technique. The sawtooth features in the spectra are interpreted as evidence of a regular spherical shell structure with magic numbers,N 0, scaling approximately with the cube root of the number of sodium atoms. Altogether twelve shell closings are observed,N 0=2, 8, 20, 40, 58, 92, 138, 196, 260, 344, 440 and 558. There is also a pronounced odd-even staggering all the way up toN=70. The experimentally observed intensity changes for the clusters around the magic numbers are discussed in terms of the electronic free energy,F(N), calculated at finite temperature, and the second differences of the free energy Δ2 F(N)=F(N−1)−2F(N)+F(N+1). The processes behind the non-uniform abundance distributions, and the thermodynamics of finite electron systems with non-uniform level spacings are discussed on this basis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01448252
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  • 97
    Digitale Medien
    Digitale Medien
    Semiclassical variational study of size effects in neutral and charged jellium droplets (1991)
    Springer
    The European physical journal 19 (1991), S. 55-58 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 36.40 ; 31.20
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract An analytic expression for the total energy of metallic clusters composed ofN identical atoms of valencev and with net chargeQ is obtained by means of a variational solution of the Thomas-Fermi-Weizsäcker energy density functional within the spherical jellium model. The minimum energy is given as an expansion in decreasing powers of the cluster radiusR=r s Z 1/3, withZ=vN andr s the radius per electron of the bulk metal. The coefficients are obtained as functions ofr s . Terms of volume (R 3), surface (R 2), curvature (R), constant (R 0), (1/R) and (1/R 2) are clearly separated in the formula, as well as the different contributions (kinetic, coulombic and exchange-correlation) to each of them. The asymptotic values (R→∞) for the work functions,W(r s ), and surface energies σ(r s ), are compared to analogous semiclassical and Kohn-Sham calculations of jellium-like surfaces and to the experimental values. The size dependent behaviour of chemical potentials, μ(R), electron affinities,AF(R), and ionization potentials,IP(R), are easily obtained for any kind of metallic clusters. In particular we discuss the Coulomb and quantum corrections to the coefficients β, δ in the asymptotic formulae:IP≃W+β/R andAF≃W+δ/R.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01448254
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  • 98
    Digitale Medien
    Digitale Medien
    Absolute cross sections for electron impact ionization of Ag2 (1991)
    Springer
    The European physical journal 19 (1991), S. 77-79 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 34.80G ; 36.40 ; 35.20V
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The previously measured relative cross section function for electron impact ionization (EII) of neutral Ag2 has now been calibrated quantitatively by combining the electron impact ionization with in situ non resonant two photon ionization (NR2PI). By comparing the NR2PI saturation intensities measured for Ag 2 + and Ag+ with the corresponding EII intensities, the ratio between the electron impact ionization cross sections (EIICS) of neutral Ag2 and Ag was determined to be σAg2/σAg=1.53 for an electron energy of 46 eV. This result agrees well with the geometricn 2/3-rule $$(\sigma X_n \sim n^{2/3} )$$ commonly proposed for the dependence of the EIICS of clustersX n on the cluster sizen.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01448259
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  • 99
    Digitale Medien
    Digitale Medien
    Thermal broadening of plasmon absorption in potassium cluster ions (1991)
    Springer
    The European physical journal 19 (1991), S. 85-87 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 36.40 ; 78.40-q
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The optical absorption spectrum around the surface plasmon peak is presented for K 21 + . Hot, charged potassium clusters are produced by an adapted liquid metal ion source. The plasmon is found to be slightly red shifted from and distinctly broader than the one reported in an experiment on colder clusters by Bréchignac et al. [3]. Mechanisms responsible for the temperature dependence of the width and position of the surface plasmon in small metal clusters are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01448261
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  • 100
    Digitale Medien
    Digitale Medien
    Response properties of sodium clusters within a jellium-like model with finite surface thickness (1991)
    Springer
    The European physical journal 19 (1991), S. 93-96 
    Details
    ISSN: 1434-6079
    Schlagwort(e): 36.40 ; 71.45.G
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The usual spherical jellium model of alkaline clusters is generalized to allow for a finite surface thickness in the positive background distribution. Static (relative stability, ionization potentials) and response properties have been calculated and the results show a better agreement with experiments.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01448263
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