ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Column liquid chromatography  (124)
  • wheat  (57)
  • Springer  (181)
  • Cambridge University Press
  • Frontiers Media
  • 2020-2022
  • 1985-1989  (181)
  • 1980-1984
  • 1975-1979
  • 1970-1974
  • 1988  (129)
  • 1985  (52)
  • 1970
Sammlung
Verlag/Herausgeber
Erscheinungszeitraum
  • 2020-2022
  • 1985-1989  (181)
  • 1980-1984
  • 1975-1979
  • 1970-1974
Jahr
  • 1
    ISSN: 1420-9071
    Schlagwort(e): Hydroxamic acid ; cereals ; maize ; wheat ; aphids ; greenbug
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary 2-β-Glucosyl-4-hydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA-Glc), the main hydroxamic acid from maize and wheat, and its aglucone, decreased survival ofSchizaphis graminum reared on artificial diets. Both compounds were toxic for aphids and acted as feeding deterrents, at concentrations as low as 1 mM. The natural concentrations of glucosides of hydroxamic acids in wheat leaves reach up to 6 mmoles/kg fresh weight, thus falling within the range in which DIMBOA-Glc causes delecterious effects to diet-fed aphids.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 46 (1988), S. 47-54 
    ISSN: 1570-7458
    Schlagwort(e): Coleoptera ; Curculionidae ; Sitophilus ; S. oryzae ; S. zeamais ; rice weevil ; maize weevil ; geographical strains ; digestion ; amylase ; diet ; barley ; corn ; maize ; rice ; wheat ; amylase inhibitors
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé La transformation de rang des valeur d'activité spécifique de l'α-amylase de 4 souches de S. oryzae et de 4 souches de S. zeamais montre que les niveaux les plus élevés de ces enzymes prédominantes s'observent chez les adultes nourris d'orge mondé ou de riz brun á grains longs. Des niveaux intermédiaires d'activité ont été obtenus chez les insectes élevés sur maïs jaune, et les niveaux les plus faibles chez ceux élevés sur blé. Bien que les extraits préparés à partir d'orge présentent une activité inhibitrice de deux isoamylases purifiées de S. oryzae, les niveaux des inhibiteurs naturels α-amylase de ces deux enzymes sont environ respectivement 2,2 et 6,1 fois plus concentrés dans le blé. L'ingestion de ces inhibiteurs d'amylase et la formation d'un complexe enzyme inactive/inhibiteur avec l'amylase secrétée antérieurement, peut rendre compte de la plus faible activité de l'amylase chez les charançons consommant du blé. Le niveau d'amylase de S. oryzae est 2 fois plus élevé que celui de S. zeamais pour toutes les souches élevées sur un régime donné. Des niveaux d'activité significativement différents ont été trouvés suivant les souches pour chacune des deux espèces. Puisque l'amylase est la principale hydrolase digestive de ces espèces, l'intensité de la modification des teneurs en amylase par la consommation de céréales peut indiquer leur adéquation comme hôtes potentiels.
    Notizen: Abstract Rank transformation of specific activity values of α-amylase across four strains of Sitophilus oryzae (L.) and four strains of S. zeamais Motschulsky indicates that levels of these predominant enzymes are highest in adults feeding on hulled barley or long-grain brown rice. Intermediate activity levels are found in weevils feeding on yellow corn (maize) and lowest levels are found in wheat-fed weevils. Although extracts prepared from barley contain inhibitory activity against two purified isoamylases from S. oryzae, levels of the naturally-occurring α-amylase inhibitors against these two enzymes are about 2.2-fold and 6.1-fold, respectively, more concentrated in wheat. Ingestion of these amylase inhibitors and formation of an inactive enzyme:inhibitor complex with previously secreted amylase may account for the lower activity of amylase in weevils of both species feeding on wheat. Amylase levels across all strains feeding on a given diet are about 2-fold higher in S. oryzae than in S. zeamais. Significant differences in activity levels were also found between strains in both species. Since α-amylase is a predominant digestive hydrolase in these species, the degree to which cereal diets affect amylase levels may indicate their suitability as potential hosts.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    ISSN: 1573-0832
    Schlagwort(e): odors ; volatiles ; microflora ; fungi ; wheat ; seasonality
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The fungal odor compounds 3-methyl-l-butanol, l-octen-3-ol and 3-octanone were monitored in nine experimental bins in Winnipeg, Manitoba containing a hard red spring wheat during the autumn, winter and summer seasons of 1984–85. Quality changes were associated with seed-borne microflora and moisture content in both ventilated and non-ventilated bins containing wheat of 15.6 and 18.2% initial moisture content. All three odor compounds occurred in considerably greater amounts in bulk wheat in non-ventilated than in ventilated bins, particularly in those with wheat having 18.2% moisture content. The presence of these compounds usually coincided with infection of the seeds by the fungi Alternaria alternata (Fr.) Keissler, Aspergillus repens DeBarry, A. versicolor (Vuill.) Tiraboschi, Penicillium crustosum Thom, P. oxalicum Currie and Thom, P. aurantiogriseum Dierckx, and P. citrinum Thom. High production of all three odor compounds in damp wheat stored in non-ventilated bins was associated with heavy fungal infection of the seeds and reduction in seed germinability. High initial moisture content of the harvested grain accelerated the production of all three fungal volatiles in non-ventilated bins.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 17 (1988), S. 147-151 
    ISSN: 1573-0867
    Schlagwort(e): time of zinc application ; wheat ; zinc sulphate ; zinc oxide ; zinc uptake
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Field experiments with wheat were conducted for two years on flood plain alluvial soils to study the effectiveness of soil application of zinc sulphate and zinc oxide at 0, 15, 45, 60, 75 and 90 days after sowing. Yield and zinc uptake of wheat increased significantly with the application of zinc. Delaying the application of both zinc sulphate and zinc oxide up to 45 days of sowing did not adversly affect the zinc nutrition of wheat. However, delaying the application for 75 or 90 days after sowing eliminated the response. Zinc sulphate, when applied within 60 days of sowing performed better than zinc oxide. In a laboratory study, zinc sulphate maintained a higher level of zinc in the soil solution than zinc oxide at least over a 3-week period.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 17 (1988), S. 137-146 
    ISSN: 1573-0867
    Schlagwort(e): Ammonium-nitrate-potassium interaction ; accumulation of reduced nitrogen ; wheat ; nitrification inhibitor ; grain ; stover
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A greenhouse experiment with wheat in 3L pots filled with a sandy loam soil in a factorial design was conducted to determine the effect of potassium on nitrogen utilization. Nitrogen was applied in three NH4-N/NO3-N ratios, 0/100, 25/75 and 50/50, at three levels: 0.75, 1.50 and 3.00gN/pot, and potassium was applied at three levels: 0, 0.5 and 1.0gK/pot. The higher levels of nitrate nitrogen with or without potassium reduced dry matter yields drastically, while the same levels of a NH4-N/NO3-N mixture of 50/50 with applied potassium reduced yields only slightly. Highest grain yield and total yield were obtained with a 25/75 mixture of ammonium/nitrate nitrogen with added potassium. Potassium addition to soil increased the utilization of nitrogen fertilizers, particularly when the ratio of ammonium to nitrate was increased. The highest uptake of reduced nitrogen was at the highest level of the ammonium to nitrate nitrogen ratio (50/50) when potassium was applied. Tillering was enhanced by an increased ammonium ratio in the nitrogen mixture, and by potassium.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    ISSN: 1573-0867
    Schlagwort(e): farmyard manure ; maize ; nitrogen ; phosphorus ; rice ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Field experiments with rice-wheat rotation were conducted during five consecutive years on a coarse-textured low organic matter soil. By amending the soil with 12t FYM ha−1, the yield of wetland rice in the absence of fertilizers was increased by 32 per cent. Application of 80 kg N ha−1 as urea could increase the grain yield of rice equivalent to 120 kg N ha−1 on the unamended soil. Although the soil under test was low in Olsen's P, rice did not respond to the application of phosphorus on both amended and unamended soils. For producing equivalent grain yield, fertilizer requirement of maize grown on soils amended with 6 and 12 t FYM ha−1 could be reduced, respectively to 50 and 25 per cent of the dose recommended for unamended soil (120 kg N + 26.2 kg P + 25 kg K ha−1). Grain yield of wheat grown after rice on soils amended with FYM was significantly higher than that obtained on unamended soil. In contrast, grain yield of wheat which followed maize did not differ significantly on amended or unamended soils.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 6 (1985), S. 171-176 
    ISSN: 1573-0867
    Schlagwort(e): Chloride ; phosphorus ; salinity ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A pot study with four levels each P (control, 6.5, 13.0, 19.5 mg kg−1) and Cl− in irrigation water (control, 30, 60, 90me l−1) was carried out to test Cl− and P interaction on wheat. It has been found that optimum P nutrition alleviates the toxic effect of excess Cl−. Highest P rate resulted in a significant yield increase upto a Cl− level of 60me l−1. Cl− depressed P content in the plant only at a Cl− level of 90me l−1, while P rates had no major impact on the Cl− concentration in the plant. Lower Cl− concentration at higher P rates are rather a dilution effect than an antagonistic one. With optimum P supply higher Cl− contents in the plants were tolerated than with a low P supply.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 8 (1985), S. 91-96 
    ISSN: 1573-0867
    Schlagwort(e): chickpea ; Egyptian clover ; field experiments ; K uptake ; mustard ; wheat ; yield
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A field experiment on a potassium deficient Typic ustochrept soil of the University Farm at Pura, Kanpur compared the responses of wheat, chickpea, mustard and Egyptian clover to added potassium for two consecutive years commencing in 1979–80. All the crops responded to potassium fertilization. Sensitivity of various crops to potassium deficiency was in the order: Egyptian clover 〉 chickpea 〉 wheat 〉 mustard. Higher sensitivity of Egyptian clover and chickpea compared to wheat was in agreement with their comparatively high root cation exchange capacity. Mustard by contrast showed higher root cation exchange capacity and exhibited least potassium sensitivity because of its higher potassium utilization efficiency. Leaf K content and total uptake of potassium by all crops was increased by applying potassium upto the highest level.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 8 (1985), S. 173-178 
    ISSN: 1573-0867
    Schlagwort(e): critical limit of Mn ; highly permeable soils ; methods and rates of Mn ; Mn deficiency ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Two field experiments were conducted on Mn-deficient soils to evaluate the efficiency of rates, methods and time of MnSO4.H2 O application for wheat. Manganese sulphate was broadcast and mixed in soils at the rate of 5 to 50kg Mn ha−1 before seeding and 10 to 40 kg Mn ha−1 as top dress at 28 days — just before first irrigation. Three sprays of 1% MnSO4·H2O unneutralised solutions were applied, the first at 26 days — 2 days before first irrigation and the others afterward at weekly intervals. Both the methods caused a significant and marked increase in grain yield. Three foliar sprays were as effective as soil applications of 20 to 40 Kg Mn ha−1 before seeding. The difference in grain yield resulting from soil applications of Mn before seeding and applications at the first irrigation was not significant. The DTPA-Mn status of 20 fields, selected on the basis of varying degree of Mn deficiency, was related to grain yield (r = 0.77**). Also grain yield of all the experiments had a significant correlation with Mn content of grain (r = 0.55** to 0.82**) and straw (r = 0.77** to 0.82**). The critical limits calculated by statistical method were 1.25, 2.18 and 3.5 mg Mn kg−1 soil for severe deficiency, deficiency and latent deficiency respectively for wheat.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 17 (1988), S. 165-176 
    ISSN: 1573-0867
    Schlagwort(e): Low-grade phosphate rock ; acid extracts ; P fertiliser ; available P ; wheat ; soil pH
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Low grade phosphate rock (PR), containing high amounts of oxides of iron and aluminium is neither suitable for fertiliser production nor useful for direct application to annual crops. The fertiliser effectiveness of P extracted by H2SO4 from a low-grade phosphate rock, PR (Christmas Island C-grade PR) was evaluated for wheat (Triticum aestivum L.) on a calcareous loam (pH 8.4) and a non-calcareous loam (pH 6.9) in field and glasshouse experiments. Superphosphate was used to compare the performance of the acid extracts of PR. In the non-calcareous loam soil, crop establishment and yield were significantly reduced by the acid extracts of PR due to increased acidity. In the calcareous soil, however, the acid extracts of PR performed as well as superphosphate; similar or even higher crop yields were obtained with the former, especially when applied near the seed. The acid extracts of low-grade PR may, therefore, have a role in calcareous soils, where the extract can be applied directly or added in the irrigation waters to supply P to crops.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 16 (1988), S. 137-155 
    ISSN: 1573-0867
    Schlagwort(e): Superphosphate ; rock phosphate ; wheat ; oats ; barley ; field experiment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Nine soil tests for phosphate were evaluated for predicting the yield and P content of wheat, barley and oats grown on a sandy soil in Western Australia: Olsen, modified Olsen 1 (soil:solution ratio 1:5), modified Olsen 2 (soil:solution ratio 1:50), Colwell, Bray 1, Bray 2, modified Bray 2T (shaking time 10 minutes), modified Bray 2C (pH 3.7) and lactate. The soil had been fertilized 5 years previously with 20 levels each of superphosphate (OSP, range 0 to 400 kg P ha−1) and Queensland rock phosphate (QRP, range 0 to 20 000 kg P ha−1). For each species and fertilizer taken separately, all the tests, except for lactate, gave a good prediction of yield. When data for OSP and QRP were pooled, Bray 2 and modified Bray 2T tests were unsatisfactory predictors of both yield and P content. A linear relationship (P 〈 0.05) between mean soil tests value (χ) and the standard deviation (σ χ ) of the test value was observed for each soil test. For QRP, the results for lactate were the most variable (i.e.σχ/χ was greatest) followed by modified Olsen 2 〉 Bray 1 〉 Bray 2 〉 Olsen 〉 modified Bray 2C 〉 modified Olsen 1 〉 modified Bray 2T 〉 Colwell. The order for OSP fertilized soil was Bray 1 〉 modified Bray 2T 〉 Bray 2 〉 Olsen 〉 Colwell 〉 modified Bray 2C 〉 modified Olsen 1 〉 lactate 〉 modified Olsen 2. For combined OSP and QRP data, the results of the Olsen 1 and Colwell extractions were the least variable. Errors in the prediction of yield (σ Y ) for all crops resulting from an error in soil test values (σχ) were calculated. For OSP-fertilized soil variability in values for the Bray-1 test provided the highest error (about 16%) in the prediction of the yield, followed by Bray 2 (12%) 〉 Bray 2T (10%) 〉 Olsen (8%) 〉 Colwell (7%) 〉 modified Bray 2C (6%) 〉 lactate (4%). Maximum error was at yields of about 65% of maximum yield. For soil fertilized with QRP, lactate provided the highest error (about 10%) in the prediction of yield, followed by the other tests (〈 6%). Maximum error was at yields of about 35% of maximum yield. The Colwell soil test gave the most accurate overall prediction of yield for both fertilizers.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 26 (1988), S. 693-703 
    ISSN: 1573-4927
    Schlagwort(e): wheat ; gliadins ; gel electrophoresis ; evolution ; genetic analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The gliadin composition of 78 spring durum wheat varieties has been studied by one-dimensional (Al-lactate,pH 3.1) and two-dimensional (first dimension, Al-lactate,pH 3.1; second dimension, sodium dodecyl sulfate-polyacrylamide gel) electrophoresis. Analysis of hybrids has shown that all components of the α zone of gliadin spectra are inherited together as blocks and are, probably, coded for by a cluster of tightly linked genes located on chromosome 6A. Fourteen variants of gliadin blocks have been identified, which can be classified into five families on the basis of component composition. All families but one have analogues among chromosome 6A-controlled blocks of bread wheat. The results indicate that some of the genome A diploid genotypes that were ancestors of durum wheats were also ancestors of bread wheats and that polyploid wheats were produced by repeated allopolyploidization events, as has been suggested earlier.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 26 (1988), S. 693-703 
    ISSN: 1573-4927
    Schlagwort(e): wheat ; gliadins ; gel electrophoresis ; evolution ; genetic analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The gliadin composition of 78 spring durum wheat varieties has been studied by one-dimensional (Al-lactate,pH 3.1) and two-dimensional (first dimension, Al-lactate,pH 3.1; second dimension, sodium dodecyl sulfate-polyacrylamide gel) electrophoresis. Analysis of hybrids has shown that all components of the α zone of gliadin spectra are inherited together as blocks and are, probably, coded for by a cluster of tightly linked genes located on chromosome 6A. Fourteen variants of gliadin blocks have been identified, which can be classified into five families on the basis of component composition. All families but one have analogues among chromosome 6A-controlled blocks of bread wheat. The results indicate that some of the genome A diploid genotypes that were ancestors of durum wheats were also ancestors of bread wheats and that polyploid wheats were produced by repeated allopolyploidization events, as has been suggested earlier.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 10 (1988), S. 303-310 
    ISSN: 1573-5028
    Schlagwort(e): chloroplast gene ; monocot ; psbA ; transcription ; wheat ; 5′ end
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have mapped and cloned the wheat chloroplast gene (psbA) that encodes the 32 kd polypeptide of Photosystem II. The psbA gene is located in the large single copy region adjacent to one inverted repeat and is transcribed toward the latter. The sequence of the 5′ end of the wheat gene is homologous with dicot psbA genes. We have located the 5′ terminus of the wheat psbA RNA to a position 83 nt upstream of its coding region. The same psbA RNA species was capped in vitro by guanylyltransferase, establishing that its 5′ end is a transcription start site. Regions which resemble procaryotic -10 and -35 promoter elements are located immediately upstream of the wheat psbA transcription initiation site.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 11 (1988), S. 633-639 
    ISSN: 1573-5028
    Schlagwort(e): wheat ; triplet protein (triticin) ; legumin ; amino acid sequence homology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have obtained several amino acid sequences from purified polypeptides of a wheat endosperm storage globulin previously described as ‘triplet’ protein. The amino acid sequence data supported by immunochemical analysis using anti-oat 12S globulin antibodies, provide definitive evidence that the triplet protein is homologous to pea legumin and related seed storage proteins of oats, rice and several dicotyledonous species. Thus, it is now proposed that the triplet protein of wheat be renamed ‘triticin’. The oat globulin antibodies also cross-reacted strongly with the high-molecular-weight (HMW) glutenin subunits which have been implicated in bread-making quality.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 11 (1988), S. 833-843 
    ISSN: 1573-5028
    Schlagwort(e): mitochondrial DNA ; transfer RNA genes ; rearrangement ; recombination ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In the course of isolating tRNA genes from wheat mtDNA, we have found the same tRNAPro gene in two different Hind III restriction fragments, H-P1 (0.7 kbp) and H-P2 (1.7 kbp). Sequences immediately flanking these duplicate genes are closely related, although not identical; sequence comparisons suggest that multiple rearrangements have occurred in the vicinity of the H-P2 tRNAPro gene, relative to the H-P1 version. The chimeric nature of H-P2 is emphasized by the presence of sequences that are also found upstream of the wheat mitochondrial 26S rRNA gene, as well as sequences derived from chloroplast DNA. Comparison of H-P2 with H-P1 plus upstream sequences provides some insight into possible molecular events that might have generated H-P2. In particular, such comparisons suggest a model in which the homologous sequences in H-P2 are seen to be derived from H-P1 plus upstream sequences as a result of an intragenomic, site-specific rearrangement event, followed by amplification of the product, its fixation in the mitochondrial genome, and subsequent sequence divergence (single base changes as well as insertions/deletions of up to 50 nucleotides). The results reported here implicate particular primary sequence motifs in certain of the rearrangements that characterize H-P2.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 10 (1988), S. 251-262 
    ISSN: 1573-5028
    Schlagwort(e): mitochondria ; mitochondrial DNA ; transfer RNA ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have begun a systematic search for potential tRNA genes in wheat mtDNA, and present here the sequences of regions of the wheat mitochondrial genome that encode genes for tRNAAsp (anticodon GUC), tRNAPro (UGG), tRNATyr (GUA), and two tRNAsSer (UGA and GCU). These genes are all solitary, not immediately adjacent to other tRNA or known protein coding genes. Each of the encoded tRNAs can assume a secondary structure that conforms to the standard cloverleaf model, and that displays none of the structural aberrations peculiar to some of the corresponding mitochondrial tRNAs from other eukaryotes. The wheat mitochondrial tRNA sequences are, on average, substantially more similar to their eubacterial and chloroplast counterparts than to their homologues in fungal and animal mitochondria. However, an analysis of regions ∼ 150 nucleotides upstream and ∼ 100 nucleotides downstream of the tRNA coding regions has revealed no obvious conserved sequences that resemble the promoter and terminator motifs that regulate the expression of eubacterial and some chloroplast tRNA genes. When restriction digests of wheat mtDNA are probed with 32P-labelled wheat mitochondrial tRNAs, 〈20 hybridizing bands are detected, whether enzymes with 4 bp or 6 bp recognition sites are used. This suggests that the wheat mitochondrial genome, despite its large size, may carry a relatively small number of tRNA genes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 76 (1988), S. 933-940 
    ISSN: 1432-2242
    Schlagwort(e): Gliadin ; Two-dimensional electrophoresis ; F1 monosomic analysis ; chromosomal assignment ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The gliadin components from four bread wheat cultivars: Chinese Spring, Capelle Desprez, Holdfast and Pane-247 and their monosomic F1s for the chromosomes of homoeologous groups 1 and 6 have been analyzed by two-dimensional (2-pH) polyacrylamide gel electrophoresis. Chromosomal location of gliadin genes and the allelic differences were well established by analyzing the different F1 monosomic hybrids, electrophoretical patterns and differences in relative staining intensity. A new gliadin encoded by a gene located on chromosome 6B in Chinese Spring is described. The two-dimensional patterns of gliadin in the other three varieties and the chromosomal location of their genes are reported for the first time. Relationships between gliadins in the two-dimensional patterns and the traditional system for their nomenclature are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 19
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Reversed-phase ; Codeine phosphate drug substance ; Opium alkaloids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A rapid procedure for the evaluation of codeine phosphate drug substance derived from poppy straw or opium concentrate is described. The gradient HPLC procedure employs a pH 2.5 phosphate buffer, methanol and acetonitrile mobile phase at 40°C and a μBondapak C-18 column. Eight opium alkaloids, including the four major alkaloids, are separated from each other. The paper describes details of the assay procedure and presents data documenting the linearity, specificity, precision, and sensitivity of the method.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 20 (1985), S. 335-342 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; External variance determinations ; Column and system compatibility ; Microbore and fast LC
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The demand for faster, more economic and convenient high-efficiency LC analyses has led to the development of microbore and fast columns. However, to utilize their benefits, the low column dispersions produced by these new technologies necessitate low external variances in the total system. This paper describes the determination of the external variance of microbore, fast and conventional LC systems by a column method. Compatibility with the relevant column technologies is evaluated by a method involving the comparison of the external and column dispersions. Direct comparison of chromatograms of an 8-component mixture, on a set of columns of various diameters and lengths, shows the relative speed, economy and sensitivity obtainable in practice. The problem of reduced sample loadability is considered and the practical solution of peak compression illustrated.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 21
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Retention prediction system ; UV multichannel detector ; Polycyclic aromatic hydrocarbons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The retention prediction system assisted by a micro-computer coupled with an UV multichannel detector has been investigated in the separation of polycyclic aromatic hydrocarbons. The method offered very precise identification of components in NBS-SRM-1647 sample without any standard reference substances. It has been proven that the system makes very precise, non-pollutive and convenient environmental analysis possible.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 20 (1985), S. 313-322 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Tetracyclines antibiotics ; Quantitation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The use of high-performance liquid chromatography (HPLC) for the identification and determination of tetracycline antibiotics is reviewed. HPLC chromatograms provide fast identification by retention time, tR, and precise quantitation by measurement of peak height or peak area. For separation of tetracycline compounds, most HPLC methods use reversed-phase C18 or C8 columns and UV detection. The HPLC solvent system should have a pH of about 6 to prevent steric changes in the tetracycline molecule. For accurate quantitation it is necessary to avoid tailing and this is accomplished by adding a zwitter ion to the solvent system. Methanol and acetonitrile are frequently used as organic modifiers in these solvent systems. In a single analysis, HPLC methods can be used to separate as many as nine or ten commercially used tetracycline compounds and to determine four to five tetracyclines in commercial tetracycline preparations or in biological fluids.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 23
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Resolution of optical isomers ; Chiral column ; Pyrethroids ; Fenvalerate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The separation of the optical isomers of fenvalerate [cyano(3-phenoxyphenyl)methyl 2-(4-chlorophenyl)-3-methylbutyrate] has been carried out by high-performance liquid chromatography (HPLC) on a chiral column with (R)-N-3,5-dinitrobenzoyl-phenyl-glycine (DNBPG) covalently bonded on aminopropyl silica and eluted with mixtures of methanol, 2-propanol, and hexane. The system was applied to the analysis of Pydrin®, an emulsifiable concentrate formulation of fenvalerate, and to the residue analysis of fenvalerate in milk samples. For the analysis of Pydrin® the only requirement was the proper dilution of Pydrin® with hexane. For the analysis of residues in milk, fenvalerate was extracted with hexane after precipitating the milk proteins with acetonitrile and removing the precipitate by filtration; the hexane extract was concentrated to small volume and filtered before being analyzed by HPLC.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 20 (1985), S. 487-494 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Size-exclusion chromatography ; Controlled-porosity glasses ; Boron-enriched glass surface ; Adsorptive properties
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Controlled-porosity glasses (CPG) are sieves for macromoleculars, very widely applied in chromatographic columns for the separation of polymers and biopolymers by means of size-exclusion chromatography (SEC) and affinity chromatography. This paper deals with the influence of the thermal treatment of CPG on the elution of polymers in SEC columns. The problem is examined for a few mobile phases and for glasses having different porosities. Additionally, the SEC results obtained are compared with the adsorption properties of the glases investigated.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 31-36 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Radioactivity detector ; Solid scintillator ; Fibre-packed flow cells
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A new type of flow-cell radiation detector for use in liquid chromatography which is packed with aligned scintillator fibers is described. A primary advantage of the fiber packed cell is that light generated by the scintillator is absorbed to a much less extent by the fibers than by the powder scintillator used in conventional flow cells. A detection efficiency of 55% has been obtained for carbon-14 using 0.1-mm diameter hand-pulled glass fibers. Computer modeling has shown that even better results can be obtained by using smaller and more uniform diameter fibers which will allow better packing. The fiber cell also demonstrates back pressures which are a factor of 50 less than the conventional cell and much less susceptibility to absorption of compounds because of its lower surface area.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 854-860 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Polystyrene ; Gradient elution ; Turbidimetry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Polystyrene samples of narrow molecular-weight distribution have been eluted according to their molecular weight from columns packed with bare silica Si50, phenyl, or C18 bonded phase by gradients of methanol and tetrahydrofuran (THF) or ofiso-octane and THF. Among the six combinations investigated,iso-octane/THF with a silica column formed a proper normal-phase system whereas methanol/THF with a C18 column formed a proper reversed-phase system. The combinations of C18 column andiso-octane/THF or of Si50 column and methanol/THF gradient did not correspond to the approved polarity rules in high-performance liquid chromatography but were nevertheless effective in separating polystyrene mixtures by molecular weight. Methanol andiso-octane are nonsolvents for polystyrene whereas THF is a solvent. The solubility of polystyrene as a function of molecular weight and concentration was determined by means of turbidimetric titration of solutions in THF with the nonsolvents used in the gradients. The solubility and elution characteristics were almost identical on C18 columns or in methanol/THF combinations. The elution from phenyl bonded phase and Si50 columns usingiso-octane/THF gradients required more THF than the solubility experiments. Information is also given on the occurrence of multimodal elution patterns.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 25-30 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Polycyclic aromatic compounds ; Alkylated PAC ; Retention characteristics ; Normal phase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Retention characteristics of series of polymethyl and mono-n-alkyl derivatives of benzene and pyrene, and also of parent polycyclic aromatic hydrocarbons (PAH), were studied using silica and aminopropyl- and cyanopropyl-modified silica. Differences in the selectivities for the studied compound groups were found between the three phases. Deviations from linear behaviour in plots of log (k′)vs. carbon number were observed for the methyl series. These are explained in terms of differences in π-electron delocalisation within the aromatic ring systems. Further, the effect of methyl substitution on selectivity decreased with an increasing number of aromatic rings. Results were obtained which indicated that the primary adsorption site in a cyano column used in normal phase mode, at least for PAH molecules, is the cyano group.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 43-50 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Reversed phase ; Void volume ; Adsorption isotherms
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary In reversed-phase liquid chromatography with n-alkyl bonded silica, the dead volume (V0) of the column is theoretically indeterminate owing to adsorption of organic modifier on n-alkyl chains and of water on silanol groups. With binary mobile phases, retention volumes of the mobile phase components and of their deuterated species are relaeed to the adsorption isotherms and V0 by equations which can be solved with some assumptions on the adsorbed layer composition. Methanol-water and acetonitrile-water systems are studied. As the experimental excess isotherm shows a linear part in the concentration range 50–80% in organic modifier, the hypothesis of an adsorbed layer of constant composition in this range is possible. When increasing the water content of the mobile phase, adsorption of water occurs up to saturation of silanol groups. Then the assumption of a constant water content for a mobile phase having more than 50% of water is applied. With the hypothesis of a constant adsorbed content of organic modifier when the eluent has more than 80% of organic modifier, V0 and the absolute isotherms are calculated over the entire range of mobile phase composition. Experimental retention behavior of the mobile phase components are totally explained by these V0 determinations. The retention times of commonly used V0 markers are compared with V0 values. It is shown that, when buffering the eluent, no visible effect on the distribution equilibrium is observed, so that injection of concentrated potassium nitrate is a convenient method to measure V0. With a few solutes with are UV detectable it is possible to measure V0 whatever the mobile phase composition in methanol-water and acetonitrile-water systems.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 29
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Stationary phase solubility parameters ; Cyano-silica ; Amino-silica ; Diol-silica
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Extended solubility parameters have been determined for aminopropyl, cyanopropyl and 1,2-dihydroxypropyl propyl ether (diol) normal bonded-phase HPLC columns. Parameters were calculated from both the retention data of solutes (partition model) and empirically determined solvent strengths (adsorption-displacement model). The use of solvent strengths to calculate solubility parameters for these silica-based bonded stationary phases appears to be superior, since this technique avoids many of the problems that arise from their inherent heterogeneity. Normalized solubility parameters were also used to position these columns on a stationary phase selectivity triangle. The amino and cyano phases appear in regions of the tringle expected based on the properties of the pure liquids, but an ether linkage in the diol apparently neutralizes some of the acidity expected from this phase.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 999-1003 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Macrolide antibiotic azithromycin ; Intermediates of azithromycin ; Optimization of separation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary HPLC is the most convenient method for the assay of the azithromycin (10-dihydro-10-deoxo-11-methyl-11-azaerythromycin A), a semisynthetic macrolide antibiotic and its reaction intermediates. Data concerning the effects of pH, temperature and column type are presented. The analytical procedures enabling the reliable assay of azithromycin and its intermediates, as well as other impurities are defined. Use of a reversed-phase octadecyl column, a pH of 9.3–9.5, and isocratic mode at ambient temperature are the best conditions of analysis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 31
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Metabolic disorders ; Xanthine and 2,8-dihydroxyadenine ; Urine analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary 2,8-Dihydroxyadeninuria and xanthinuria are inborn enzyme disorders which must be under lifelong therapeutic control. Quantitative determination of 2,8-DHA and xanthine using reversed phase HPLC was performed. A new application for the separation of purines shortens analysis-time. Examples of the determination of 2,8-DHA and xanthine before and under certain therapies are shown. Long term monitoring of the patients offers the possibility of a reliable prophylaxis against stone recurrence.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 32
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Indirect detection of non-electrolytes ; Simulation of induced peaks ; RP systems
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Induced peaks observed in indirect detection of nonelectrolytes in high-performance liquid chromatography are simulated. The equation representing the signal intensity of the induced peaks is derived, and it is verified by the experimental results. The peak area is proportional to (K b ′ +1) k a ′ /| a ′ —k b ′ |, where k a ′ ad k b ′ are the capacity factors of the visualization agent and the analyte, respectively.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 162-166 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Ion chromatography ; Analysis of metal ions ; Post column derivatisation ; Amperometric detection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A method for determination of metal ions subsequent to separation by ion chromatography has previously been developed. The method is based on Indirect Amperometric Detection whereby the decrease in the oxidation current, due to a dithiocarbamate ligand added post column, is monitored. Upon elution from the chromatographic column the metal ions are complexed by the ligand. As the complexes formed are electroinactive at the applied potential, the background current decreases according to the metal ion concentration. The method developed in this work involves addition to the reagent of Zn(II) as a auxiliary metal ion to displace the analyte metals from the chromatographic eluent ligand complexes after separation. Sodium bis(2-hydroxy-ethyl) dithiocarbamate was used as the postcolumn derivatising reagent. The addition of Zn(II) to the reagent causes some unforeseen behaviour in the chromatographic system.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 199-204 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Column switching ; Catecholamines ; Urine ; Serum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary We developed an automated, two-column HPLC-method that can be used routinely to quantify the catecholamines norepinephrine and epinephrine in body fluids. The method is based on a new, laboratory-prepared SEC-HPAC column material, on the application of a microprocessor-controlled column-switching technique, and on the use of an integrated reaction system for postcolumn derivatization and trihydroxyindol-fluorescence monitoring. It allows the direct injection (upto 500 μl) of an appropriate biological fluid and distinguishes on its integrated sample-processing mode, its practicability, its chemoselectivity and-specivity, its detection limit (2 pg), its within- and between-run precision and its speed of analysis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 319-323 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Pheophytinatonicke(II) ; Chlorophyll ; Pheophytin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary HPLC determination of pheophytinatonicke(II) (Pheo-Ni) prepared by the replacement of magnesium(II) in chlorophyll with nicke(II) is described. The good separation of PheoNi was obtained by using chemically bonded C18 as the stationary phase and acetone-methanol (50∶50, vol/vol) as the mobile phase. Conventional spectrophotometric method was also used for the determination of PheoNi. For the synthetic samples prepared by mixing (pheophytinato a) nicke(II) [(Pheo-a) Ni] and (pheophytinato b) nicke(II) [(Pheo-b) Ni], analytical values obtained by the spectrophotometric method were very high compared to those obtained by HPLC. In the proposed HPLC method, (Pheo-a) Ni and (Pheo-b). Ni could be determined in the concentration range of 0.028–30μg/ml and 0.038–30μg/ml with relative standard deviations (n=10) of 3.1% and 0.8%, respectively.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 36
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Flavonoid compounds ; Structure-retention relationships ; Reversed-phase systems
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Reversed-phase HPLC retention behaviour of different flavonoid compounds in different columns and with a range of methanol-buffer eluents was examined. Repeatibility and reproducibility of logk′ and Δlogk′ values were analyzed. Sharp group contributions, expressed as Δlogk′, were observed. These did not depend significantly on acid modifier type, column packing characteristics (C8 and C18) and dimensions (5,7 and 10μm) or the percentage of methanol in the mobile phase. A list of twelve group contributions is presented which is in agreement with literature data.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 443-446 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Large scale separations ; Dissolution of silica ; Metallic contaminants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Possible contamination of purified product by the silica matrix is of considerable importance when considering process scale high-performance liquid chromatography (HPLC) as a separation methodology. The stability of silica supports in normal phase, reversed phase and affinity chromatography modes has been examined with organic solvents and water. Both inorganic and organic components were found, contributed by the support, and the chromatographic and distillation equipment. In all cases, based on assumed values of production, they were found to contribute less than 0.01% of impurities. In critical cases crystallisation or dialysis may be considered as a last stage of purification, with re-chromatography to maximise yields.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 523-525 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Fast atom bombardment mass spectrometry ; Nonionic detergents
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Microcolumn liquid chromatography (LC) combined with fast-atom-bombardment mass spectrometry (FABMS) was applied to the analysis of nonionic detergents. The porous silver filter attached to the top of the capillary fused-silica tubing worked as the interface for coupling of micro LC and FABMS.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 577-581 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Process scale ; Examples of separations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The flexibility of process scale high performance liquid chromatography is demonstrated by three examples of reversed-phase separations (a) a standard purification (b) isolation of trace compounds, and (c) recovery from crystallisation mother liquors. It was shown that a material, thought to be acceptably pure, contained a toxic impurity, and a remaining impurity, a previously unseen component of potential therapeutic interest. Favourable cost data were indicated for example (3).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 717-720 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Reversed-phase chromtography ; Antifungla agent ; Pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A high-performance liqid chromatographic method is reported for the measurement of miconazole in systemic, fungal infectious patients. Pharmacokinetic data are presented for a single patient receiving miconazole therapy. Sample preparation involves protein precipitation by acetonitrile (1:1, vol/vol). Analyses are carried out on a reversed-phae chromatographic system using octadecylsilane stationary phase: a mobile phase consisting of 0.05 M acetate buffer (pH 7.4)acetonitrile (20:80, vol/vol) is used to elaute miconazole is quantified on the basis of ultraviolet absorption at 220 nm. The precision of the method ranged from 3.21% at 0.5 mg/L to 0.85% at 2.0 mg/L. The limit of quantification was established as 0.1 mg/L. Interference from other drugs that are co-adimistered such as amphotericin B, 5-fluorocytosine of ketoconazole and most other comonly encountered drugs was not observed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 41
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Fractional factorial experimental designs ; Ruggedness test ; Method validation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Recently much attention has been directed to the validation of analytical methods. The level of validation will depend on the method application. If a method is developed for general use, for instance by different analysts, instruments or laboratories, then the effect of these changes need evaluation. This is normally referred to as ruggedness testing, where the limitations of the method to changes in the specified conditions are examined. This paper examines the use of Plackett-Burman fractional factorial experiment designs for ruggedness testing in high performance liquid chromatography (HPLC). The ability of these designs to identify confounding effects is applied to the stability indicating analysis of Salbutamol and its major degradation product, AH4045. The results show that confounding effects, proving extremely pertinent to HPLC, can be identified. The assay proved rugged to most tested changes although not to the use of column packing material from different manufacturers.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 42
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Alkyl-bonded phases ; Retention behaviour ; Ligand density ; n-alkyl chain length
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Two series of bonded phases were synthesized employing LiChrospher Si 100, 10 μm and n-alkyldimethylmonochlorosilanes as silanizing reagents. In series A the n-alkyl chain length, n, of the bonded phase was varied between 1 and 20 at a constant ligand density of 3.5±0.2μmol·m−2. In series B the ligand density, d, was gradually changed from 0 to 4.1μmol·m−2 on the C1, C4, C6, C8 and C18 bonded phases, respectively. The capacity factors of benzoic acid esters and anilines as solutes were found to increase linearly with the n-alkyl chain length of packings at constant eluent composition (series A) up to a so-called critical chain length, ncrit, where the capacity factor remained constant. ncrit was in the range from 11 to 14. The same pattern was observed when plotting the solute capacity factor against the ligand density of the packing at constant n and constant eluent composition (series B). The critical ligand density, αcrit, varied between 2.3 and 3.2 μmol·m−2 depending on n and the solute. Furthermore, solute retention was slightly higher on RP packings with an even number of carbon atoms in the alkyl chain than on those with an odd number. These findings are consistent with the results of Berendsen and de Galan (J. Chromatogr., 196, 21 (1980)), Dill (J. Phys. Chem., 91, 1980 (1987)) and Simpson and Lau (to be published). The observed phenomena reflect the dynamic structure of RP silicas which are related to the mobility of solvated n-alkyl chains. Due to the lack of a precise conformational analysis of the surface of RP silicas, a semiquantitative model was applied to interprete the described dependencies.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 43
    ISSN: 1573-5028
    Schlagwort(e): wheat ; chloroplast genes ; ATP synthase ; methionine tRNA gene
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The nucleotide sequences of the chloroplast genes for the alpha, beta and epsilon subunits of wheat chloroplast ATP synthase have been determined. Open reading frames of 1512 bp, 1494 bp and 411 bp are deduced to code for polypeptides of molecular weights 55201, 53796 and 15200, identified as the alpha, beta and epsilon subunits respectively by homology with the subunits from other sources and by amino acid sequencing of the epsilon subunit. The genes for the beta and epsilon subunits overlap by 4 bp. The gene for methionine tRNA is located 118 bp downstream from the epsilon subunit gene. Comparisons of the deduced amino acid sequences of the alpha and beta subunits with those from other species suggest regions of the proteins involved in adenine nucleotide binding.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 44
    ISSN: 1573-5036
    Schlagwort(e): black gram ; boron deficiency ; borax rates ; green gram ; hollow heart ; hot-water-soluble boron ; kernel boron ; leaf boron ; peanut ; rice ; soybean ; sunflower ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effect of boron (B) on peanut and soybean was examined in two omission and one B fertilizer rate trial on a Typic Tropaqualf in Northern Thailand. The B rate trial was combined with a comparison of the response of sunflower, green gram, black gram, wheat, and rice in addition to peanut and soybean grown in irrigated rice-based cropping sequences over two years. Omitting B induced the hollow heart symptom in 10% of peanut kernels with the incidence of hollow hearts closely related to B concentration in the kernels. Omission of B had no effect on the appearance of soybean seed or on the grain yield of either soybean or peanut. In the B rate experiment, omitting B depressed grain yield by 50% in sunflower and by 40% to 80% in black gram, induced B deficiency symptoms in green gram and the hollow heart symptom in peanut kernels, but had not significant effect on the grain yield of soybean, peanuts, rice, or wheat. B deficiency apparently depressed grain yield in black and green gram by delaying or inhibiting reproductive development thus reducing pod set.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 4 (1985), S. 101-109 
    ISSN: 1573-5044
    Schlagwort(e): wheat ; cryopreservation ; suspension ; callus ; plant regeneration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Wheat (Triticum aestivum L. cv. Norstar) suspension cultures and regenerable calli initiated from immature embryos can be cryopreserved in liquid nitrogen temperature (−196°C) by slow freezing (0.5°C/min) in the presence of a mixture of DMSO and sucrose or sorbitol. Cold hardening or ABA treatment before cryopreservation increased the freezing resistance and improved the survival of wheat suspension culture in liquid nitrogen. Callus culture, established from immature embryos, prefrozen in 5% DMSO and 0.5M sorbitol survived liquid nitrogen storage and resumed plant regeneration after thawing. The results confirm the feasibility of long term preservation of wheat embryo callus by cryopreservation and retention of plant regeneration ability.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 46
    ISSN: 1573-5060
    Schlagwort(e): Tricticum aestivum ; wheat ; yield ; genotype x environment ; retrospective ; environments
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The identification of relevant but diverse environments for the assessment of the relative performance of wheat cultivars was developed by using conventional and pattern analysis procedures. The utility of weighting environments on proximity to a hypothetical most frequently encountered environment, to improve the quality of the predictive inference of relative cultivar performance, was also assessed. There was an increase in the agreement of the relative yield of cultivars obtained in different years using this technique.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 34 (1985), S. 559-571 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; ear emergence ; number of leaves ; number of spikelets ; photoperiod ; vernalization ; geographical distribution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Differences in response to photoperiod and vernalization and genetic variation independent of photoperiod and vernalization (earliness per se), affecting time of ear emergence of wheat, were identified in controlled environment experiments with 33 varieties of diverse geographical origin. The results were compared with an analysis of time of ear emergence of 10409 T. aestivum accessions from the USDA Small Grain Collection grown from autumn sowings in Pendleton, Oregon, and spring sowings in Fargo, North Dakota. The effect of differences in photoperiod and vernalization sensitivity on time of ear emergence was similar to the effect of earliness per se, both under controlled environment conditions and in the field. Most of the accessions from low latitude regions reached ear emergence rapidly owing to their insensitivity to photoperiod and vernalization and earliness per se factors accelerating ear emergence. Lateness was common among accessions from Northern Europe, Afghanistan and Turkey, which was due to sensitivity to photoperiod and vernalization, and to earliness per se factors delaying ear emergence. The physiological basis of earliness per se is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 39 (1988), S. 137-144 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Hordeum vulgare ; barley ; boron toxicity ; variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The growth and yield of seven wheat and two barley cultivars or lines, previously found to show different degrees of boron tolerance under field conditions, were compared in a pot experiment at a range of soil boron treatments. Soil treatments ranged up to 150 mg/kg applied B. Extractable B in soils ranged up to 103 mg/kg. At the highest B treatment seedling emergence was delayed, but the percentage emergence was not reduced. The degree of boron toxicity symptom expression varied between the wheat cultivars and lines, with the two most tolerant, Halberd and (Wq*KP)*WmH)/6/12, displaying the least symptoms. The concentration of boron applied to the soil which produced a significant depression of growth and yield varied between cultivars. For example, the yield of (Wq*KP)*WmH)/6/12 was not affected at the 100 mg/kg applied boron treatment, while the grain yield for (Wl*MMC)/W1/10 was significantly reduced at the 25 mg/kg treatment. There was a linear increase in boron concentration in tillers at the boot-stage with increasing concentration of boron in the soil. The most boron tolerant genotypes had the lowest tissue boron concentrations in each of the treatments. Halberd and (Wq*KP)*WmH)/6/12 had approximately half the boron concentrations of the more sensitive genotypes at the 25 and 50 mg/kg treatments. Differential tolerance of boron within the tissue was also observed. Both Stirling and (Wl*MMC)/W1/10 had significantly reduced total dry matter and grain yields at the 25 mg/kg treatment, while the concentrations of boron in boot stage tillers at this treatment were 118 and 100 mg/kg, respectively. On the other hand, Halberd and (Wq*KP)*WmH)/6/12 had tissue boron concentrations of 144 and 131 mg/kg, respectively, at the 50 mg/kg treatment but yield was unaffected. The relative responses in the pot experiment, for wheat, were in close agreement with field results. Halberd and (Wq*KP)*WmH)/6/12 had the highest grain yields, with the lowest concentrations of boron in the grain when grown under high boron conditions in the field. In pots these two genotypes proved to be the most tolerant of boron. For barley the advantage in grain yield in the field, expressed by WI-2584 compared with Stirling, was not repeated in pots. WI-2584 was, however, more tolerant than Stirling on the basis of total dry matter production. The results show that useful variation in boron tolerance exists among wheat, and that breeding should be able to provide cultivars tolerant to high levels of boron.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 110 (1988), S. 140-142 
    ISSN: 1573-5036
    Schlagwort(e): Gaeumannomyces graminis ; roots ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A root assessment tray was designed for the meticulous assessment of take-all on wheat seedling roots from soil bioassays. Subsequently, the detection of lateral root infections (in addition to the more obvious infections on main axes of seminal roots) resulted in increased estimates of propagule numbers of the take-all fungus (Gaeumannomyces graminis var.tritici) for 196 of the 368 soil samples bioassayed in a field study conducted in Western Australia between 1984 and 1986.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 105 (1988), S. 169-178 
    ISSN: 1573-5036
    Schlagwort(e): development ; fibrous root growth ; geotropism ; root deflection ; root model ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A model is described which simulates the growth of fibrous root systems. The root growth is specified in terms of growing time, numbers of axes, initiation times of axes, growth rates and branching characteristics of the roots, and characteristics governing the direction of root growth. The model generates a representation of the root system in which the locations of all branches and root tips are recorded in three-dimensional coordinates, and updates this representation in discrete time steps until the specified growing time is reached. Data are presented from a simulation of wheat root growth by the model. The simulated root system is represented pictorially and also graphically in the form of root length and root tip number profiles which are stratified by branching order class. The pictorial representations produced by the model are much more realistic than any which have been produced by past root growth models, and the graphical representations show trends in root length and root tip numbers which are the same as those commonly observed in real roots.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 109 (1988), S. 128-130 
    ISSN: 1573-5036
    Schlagwort(e): nitrogen ; root pruning ; shoot ; root ratio ; Thornley's model ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In two experiments, wheat plants growing in solutions of different nitrogen concentration were subjected to root pruning. In higher concentrations of nitrogen the growth rate was higher, and the proportional allocation of growth to shoot higher, but pruning did not affect the allocation of growth at either level of nitrogen. This result gives no support to Thornley's source-sink model of the control of shoot: root ratio.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 109 (1988), S. 195-198 
    ISSN: 1573-5036
    Schlagwort(e): Anguina tritici ; Corynebacterium tritici ; disease complex ; inoculation methods ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Wheat,Triticum aestivum L. cv. Mexipak was artificially inoculated withAnguina tritici (Steinb.) under field conditions. Nematode inocula: 0, 0.1, 0.2 and 0.3 g of seed galls/50 seeds or, germinated seeds of wheat (sown in a 1-m long row) were either added as intact seed galls or as a suspension of 2nd stage juveniles. Inoculation of ungerminated seeds with juveniles produced the highest incidence of ear-cockle disease. Whereas, intact seed galls inocula produced the highest incidence of tundu disease. Ear-cockle incidence was always greater than that of tundu at all treatments. The highest reduction in grain yield was associated with the treatments that caused the highest incidence of tundu disease.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 112 (1988), S. 261-266 
    ISSN: 1573-5036
    Schlagwort(e): crown rot ; Fusarium graminearum ; interactions ; wheat ; zinc deficiency
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Wheat plants were grown at three levels of zinc nutrition in potted soil under controlled conditions. The surface soil in half of the pots was inoculated with a thin layer of milled chaff colonized byFusarium graminearum Group 1. Forty days after sowing, the plants were assessed for dry matter production and the extent of colonization by the pathogen. The concentration of zinc in the plant tissues was also determined. The zinc status of the plants ranged from severe deficiency through subclinical deficiency to sufficiency. The extent of colonization above the point of infection was decreased significantly by increasing the level of zinc supply. However, colonization of the seminal or secondary roots was not affected by zinc supply, nor was the incidence of infected plants. The unidirectional effect on resistance suggests that zinc has modified the contribution of the xylem flux to the upward spread of the pathogen.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 111 (1988), S. 171-175 
    ISSN: 1573-5036
    Schlagwort(e): hormones ; potassium status ; potassium transport ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 112 (1988), S. 45-52 
    ISSN: 1573-5036
    Schlagwort(e): barley ; boron toxicity ; genotypic variation ; mineral nutrition ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The mechanism of resistance toB toxicity in barley and wheat was studied in a solution culture experiment using several cultivars displaying a large range of sensitivity to excessB supply. Plants were cultured for 35 d atB concentrations ranging from normal to excessive (15 to 5000 μM, respectively) then examined for dry matter production and theB distribution between roots and shoots. In both species, increasedB supply was accompanied by increased tissueB concentrations, development ofB toxicity symptoms and depressed growth. At each level ofB supply, however, resistant cultivars accumulated considerably lessB than did sensitive cultivars, in both roots and shoots. Even at the lowestB supply, at which noB toxicity symptoms developed and growth was not affected, resistant cultivars maintained relatively low tissueB concentrations. No cultivar displayed an ability to tolerate high tissueB concentrations. These results indicate that sensitivity toB toxicity in barley and wheat is governed by the ability of cultivars to excludeB. If theB concentrations of tissues is used to indicate resistance toB toxicity, then cultivars have the same ranking whether cultured at a normal or excessB supply.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 34 (1985), S. 153-159 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Secale cereale ; rye ; Triticosecale ; callus culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Callus cultures were initiated from inflorescence explants of wheat, rye and triticale on MS medium supplemented with 2 mgl-1 2,4-D+5% CW or 2 mgl-1 2,4-D+0.5 mgl-1 BA. On transfer of the cultures to medium supplemented with 15% CW+0.2 mgl-1 NAA or 1 mgl-1 BA+0.1 mgl-1 IAA, shoot buds and embryoids were produced. Full fledged plantlets obtained on MS medium supplemented with NAA were transferred to the field. Cytological analysis showed the plants to be diploid. However, the regenerated plantlets were shorter, produced fewer tillers and had lower fertility compared to the control.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 34 (1985), S. 207-211 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Secale cereale ; rye ; hybrid necrosis ; intergeneric cross
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary An inbred line of rye (Secale cereale L.) has been found to carry a gene for hybrid necrosis. This gene was detected in crosses with a highly crossable wheat (Triticum aestivum L.) genotype which carries the gene Ne2. This appears to be the first report of a gene for hybrid necrosis being present in the rye genome.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 34 (1985), S. 367-370 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; frost resistance ; chromosome 5A ; reciprocal monosomic analysis ; allelic variation ; substitution line
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary F2 monosomic analysis and the direct comparisons between aneuploid series from different varieties of wheat suggest the likelihood of allelic variation. It is impossible however, from these studies to prove unequivocally that allelic variation exists. Some effects can be due to chromosome dosage rather than allelic variation. This disadvantage was overcome by using reciprocal monosomic analysis to study the genetic control of frost resistance on chromosome 5A in wheat. Data support the previous results obtained by F2 monosomic and substitution analysis. The chromosome 5A has been shown to be the one which carries the major allelic differences that distinguish wheat varieties Chinese Spring, Rannyaya 12 and Mironovskaya 808 for frost resistance.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 59
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; reciprocal F1 monosomics ; ear emergence ; number of leaves ; number of spikelets ; photoperiod ; vernalization ; growth rate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary A reciprocal F1 monosomic analysis of chromosomal differences between Spica and Bersée was carried out under controlled environment conditions. Chromosomes associated with differences in days to ear emergence, number of leaves and number of spikelets were identified. The results indicated that chromosome 2B of Spica carries a photoperiod insensitivity allele at the Ppd 2 locus. Both Spica and Bersée appear to have a vernalization insensitity allele at the Vrn 2 locus on chromosome 5B. On chromosome 3A, 4B, 4D and 6B factors were found with major effects on earliness per se, diffeences in ear emergence and number of spikelets which were independent of photoperiod and vernalization. The possibility that these factors influence growth rate is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 60
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 34 (1985), S. 233-236 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; auricle colour ; genetics ; instability of expression ; gene penetration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Only a few publications deal with the genetics of auricle colour of wheat. They report that red pigmentation is conditioned by one dominant gene, symbolized Ra. Ra is present in Egyptian local wheat cultivars. My own research showed the great instability of this character.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 34 (1985), S. 273-277 
    ISSN: 1573-5060
    Schlagwort(e): Triticum durum ; wheat ; clonal propagation ; cytokinins ; shoot proliferation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Immature embryos from five durum wheat cultivars were grown on Murashige and Skoog medium supplemented with two concentrations of kinetin or 6-benzylaminopurine (BAP). The embryos cultured on the medium containing 5 mg/l of BAP proliferated several axillary shoots. Shoot base segments subcultured on the same medium gave more shoot proliferation. The shoots developed into ear-bearing plants. This technique could be used for clonal propagation of wheat.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 62
    ISSN: 1573-5060
    Schlagwort(e): Trticum aestivum ; wheat ; gram yield ; grain protein ; seed quality ; yield components
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Wheat (Triticum aestivum L.) kernel weight is an important yield component and seed quality factor that appears to be declining with recent cultivar releases in the major U.S. wheat region. The objectives of experiments were to detmrmine the relationship between planted and harvested 1000-kernel weights and their effect on grain yield and grain protein percentage. Twelve popular hard red winter wheat cultivars were grown with recommended practices at 10 Kansas locations for three years. Rank correlation coefficients between kernel weights and grain yields and protein percentages were calculated. Correlations of planted and harvested kernel weights over all cultivars with grain yield were inconsistent, being positive for some locations and years and negative for other locations and years. Planted kernel weights and grain yields of individual cultivars were not related, but harvested kernel weights and grain yields were correlated positively for eight of the 12 cultivars. Harvested kernel weights and grain protein percentages frequently were correlated positively at individual locations, but always were correlated negatively for individual cumtivars. It was concluded that high stable harvested wheat kernel weight is important as a component of grain yield under a range of environments and that improving this trait would benefit all segments of the wheat industry.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 34 (1985), S. 833-847 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; growth analysis ; relative growth rate ; selection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary For a better insight in the effect of wide spacing on the outcome of plant selection in spring wheat, the growth of free-grown individual plants was followed in time for each of 12 cultivars. As time proceeded, the cultivar differences for per-plant weight showed progressively less relation with those for seedling weight. At anthesis, the genetic correlation with seedling weight was still about 0.80, but at final harvest it was only 0.06. This contrasted with the genetic correlation between seedling weight and final biomass in closely planted mixtures which was on the average 0.77. The outcome of selection of genotypes in isolation is therefore expected to deviate substantially from that of selection in densely planted segregating populations where the differences in initial size tend to be maintained in time. The ranking of the varieties grown in isolation changed in time because of differences in relative growth rate (RGR). The genetic variance of RGR decreased much less with time than RGR itself. Late-flowering varieties showed the higher RGR so that these varieties improved their position in the ranking in isolation. Special attention is paid to the methodology of plant growth analysis in variety experiments and in estimating means and variances of RGR.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 110 (1988), S. 101-109 
    ISSN: 1573-5036
    Schlagwort(e): bean ; influx rate ; onion ; phosphorus efficiency ; rape ; ratio ; root-shoot ; ryegrass ; spinach ; tomato ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Plant species differ in their P efficiency,i.e. the P content in soil needed to reach their maximum yield. The differences in external P requirements can be atributed to either a lower internal P requirement for optimum growth or higher uptake efficiency of the plant. The objective of this research was to investigate the reasons for different P efficiencies of seven plant species. Onion, ryerass, wheat, rape, spinach, tomato and bean were grown in a P-deficient subsoil fertilized with 0, 2, 5, 10, 20, 40 and 80 mg P 100 g−1. All species showed a strong yield increase due to P fertilization. To reach 80% of maximum yield onion and tomato needed 17 and 11 mg P 100 g−1 respectively, corresponding to a soil solution concentrations of 6.9 and 5.7 μmol P l−1, whereas ryegrass, wheat and rape needed about 5 mg P 100g−1 corresponding to only 1.4 μmol P l−1 in soil solution. These differences in external P requirement cannot be explained by differences in their internal P requirement since onion, with the highest external P requirement, only contained 0.14% P in the shoot at 80% of maximum yield, while wheat, as the most P efficient species, contained 0.28%. P efficiency was related to the uptake efficiency of the plant which is determined by both root-shoot ratio and absorption rate per unit of root (influx). Species of low efficiency such as onion, tomato and bean had low influx rates and low root-shoot ratios, whereas species of medium to high efficiency had either high influx rates (rape and spinach) or high root-shoot ratios (ryegrass and wheat). The combination of both high influx rate and high root-shoot ratio was not found in any of the species studied.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 65
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 111 (1988), S. 25-35 
    ISSN: 1573-5036
    Schlagwort(e): carbohydrate accumulation ; chloride ; salinity-phosphorus interaction ; sodium ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Foliar inorganic ion and carbohydrate concentrations were determined in wheat plants treated with factorial combinations of phosphorus fertilizer and NaCl in a glasshouse experiment. Growth reductions and visual symptoms of salt toxicity were minimized when phosphorus nutrition was adequate, and were intensified by phosphorus deficiency. Foliar sodium and chloride accumulated up to 4.0–5.5% d.w. with salinity treatment. However, ionic concentrations within corresponding leaves or distributions between leaves of plants with different phosphorus treatments were not influenced by phosphorus treatment and had no relationship to the severity of salt toxicity symptoms. This suggests that phosphorus deficiency reduced the cellular tolerance for ion accumulation. A combination of phosphorus deficiency and salinity induced an accumulation of foliar starch and sucrose despite substantial reductions in net CO2 assimilation rates. This accumulation did not occur if phosphorus nutrition was adequate, which is consistent with the roles of phosphorus in carbohydrate metabolism. It is proposed that adequate phosphorus nutrition is essential for effective ion compartmentation by contributing to efficient carbohydrate utilization in salt-stressed wheat.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 107 (1988), S. 19-23 
    ISSN: 1573-5036
    Schlagwort(e): Gaeumannomyces graminis ; pectolytic enzymes ; Phialophora graminicola ; Phialophora sp. ; virulence ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Gaeumannmyces graminis var.tritici (Ggt), Phialophora sp. (lobed hyphopodia) andPhialophora graminicola vere grown in a liquid medium with pectin and on autoclaved wheat roots (root media) and the activity of pectolytic enzymes in culture filtrates was measured. Most strains of the fungi exhibited polygalacturonate trans-eliminase activity but no pectin methylesterase activity was detected.Ggt polygalacturonase was found in culture filtrates from all the media used whilePhialophora sp. did not exhibit activity of this enzyme in the unbuffered root media. No polygalacturonase activity was demonstrated forP. graminicola. A correlation was found (r=0.548) betweenin vitro polygalacturonase activity and the pathogenicity ofGgt to wheat seedlings.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 67
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 107 (1988), S. 137-143 
    ISSN: 1573-5036
    Schlagwort(e): mineral composition ; short-term flooding ; sodic soil ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In sodic soils of the Indo-Gangetic alluvial plains of Northern India, flooding for short periods often occurs during the growing season of wheat, leading to low yields. A field study was therefore conducted to evaluate the effects of short-term flooding on growth, yield and mineral composition of wheat (Triticum aestivum Linn. emend. Fiori and Paol) in a sodic soil (pH 8.9, exchangeable sodium percentage 25). Flooding wheat for 2,4 and 6 days at the time of first irrigation (25-day old plants), significantly reduced tillering, plant height, delayed head emergence and resulted in 17.6, 29.0 and 46.7% reduction in grain yield, respectively, Flooding decreased oxygen diffusion rate (ODR) values, restricted root grwoth and reduced ion uptake, especially of N, P, K, Ca, Mg and Zn and led to higher absorption of Na, Fe and Mn. Under the conditions of this experiment, the reduced growth and yield of wheat resulting from short-term flooding was not due to Mn, Fe and Na toxicity but may be due to reduced uptake of nutrients resulting from O2 deficiency in the soil.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 68
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 12 (1988), S. 97-110 
    ISSN: 1573-5044
    Schlagwort(e): wheat ; somatic embryogenesis ; embryogenic callus ; 3,6-dichloro-o-anisic acid ; 2,4-dichlorophenoxyacetic acid ; 6-furfurylaminopurine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Nine experiments were conducted to determine effects of various culture medium addenda on induction of embryogenic calli from immature embryos of a responsiveTriticum aestivum L. genotype (PCYT 10). Effects were quatified by counting somatic embryos (embryoids) per callus. Optimal auxin concentrations to induce and maintain somatic embryogenesis were 3.62 μM 2,4-dichlorophenoxyacetic acid (2,4-D) or 9.05 μM 3,6-dichloro-o-anisic acid (dicamba). In general, dicamba permitted formation of significantly more embryoids than 2,4-D. Kinetin (6-furfurylaminopurine) at 2.56 μM or 4.65 μM significantly increased percentage scutellar callus when added to 2,4-D or dicamba-containing medium, respectively. Kinetin at 4.65 μM signficantly increased the numbers of embryoids formed when added to medium containing either synthetic auxin. Significantly fewer embryoids formed when cultures were incubated under diffuse light (16-h photoperiod). Casein hydrolysate (200 mgl-1) or L-arginine (0.23 mM) had no effect on numbers of embryoids formed, whereas L-tryptophan (0.20 mM) enhanced such formation with 2,4-D and decreased such formation with dicamba. Two additional experiments generally demonstrated that response to auxin source in the genotypes ND 7532, PCYT 20, Yaqui 50, and Oasis was similar to that in PCYT 10. The higher molar concentration of dicamba required to induce embryogenic callus coupled with more evident embryoid precocious germination and a more rapid rate of tissue necrosis upon extended incubation without subculture suggests that dicamba is metabolized more rapidly than 2,4-D inT. aestivum callus cultures.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 69
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 12 (1988), S. 299-304 
    ISSN: 1573-5044
    Schlagwort(e): callus ; plant regeneration ; isozymes ; wheat ; barley
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Callus cultures fron non-organogenic, young and one-year old, and morphogenic calli were used to assess the value of isozymes analysis for the prediction of morphogenic capacity by studying esterase, peroxidase and acid phosphatase. Basic isozyme patterns of each enzyme for the callus were retained in all the callus stages and in the callus which has differentiated into shoots. With the development of shoot and/or root some conspicuous isozymes appeared for esterase and acid phosphatase and some disappeared for peroxidase. As the isozyme changes became apparent only after shoot or root initiation these enzymes could not be used as markers to distinguish between morphogenic and non-morphogenic calli.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 15 (1988), S. 123-136 
    ISSN: 1573-0867
    Schlagwort(e): corn ; soybean ; wheat ; maximum yield ; optimum yield ; Bray P1 ; exchangeable K
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Data from 32 years of a rotation-fertility experiment were analyzed to determine the average P and K application rates required for maximum yield and for optimum yield. A four-year rotation of corn, soybean, wheat, hay was used for the first 10 years and then changed to corn-1, soybean, wheat, corn-2. Rates of P application per 4-year rotation ranged from 0 to 196 kg ha−1 and for K from 0 to 558 kg ha−1. Multiple regression equations were fitted to the mean yields per 4-year rotation for the response of each crop to P and K applications. The range in P application rates in kg of P per 4-year rotation required to get maximum yields of corn was 118 to 172, for soybeans was 134 to 150, and for wheat was 116 to 138. The range in K application rates in kg K per 4-year rotation to get maximum yields of corn was 378 to 411, for soybeans was 324 and 476, and for wheat was 11 to 323. For rates of application where P and K added exceeded crop removals, soil test P and K increased linearly with the cumulative positive balance of P and K. Where crop removal exceeded application rate, no relation was found between crop removal and soil test.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 6 (1985), S. 219-224 
    ISSN: 1573-0867
    Schlagwort(e): cowpea ; green gram ; pearl millet ; phosphate ; residual effect ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In a four year study on a wheat-green gram (or cowpea) — pearl millet intensive cropping system a total production of 9–10 tonnes of wheat equivalents per year removed 29–30kg P ha−1. If only 26 kg P ha−1 was used then total grain production as well as P uptake, was highest when all the P was applied to wheat. Only when amounts larger than 26 kg P ha−1 were applied was it justified to apply P to pearl millet and green gram (or cowpea). Productivity of the cropping system increased up to 58.5 kg P ha−1 and at this level two thirds of P was applied to wheat, while pearl millet and green gram or cowpea received the remaining one-third. A positive P balance in soil was observed only when 26 k P ha−1 yr−1 or more was applied. Pressure of growing population and per capita diminution or arable land has focussed attention on multiple cropping systems in many Asian countries [1, 2]. In North-Western India the cropping system changed from a single rainy (July–October) or winter (November–April) crop a year prior to the 1960's to two-crops-a-year (both a rainy season and winter crop) in the 1970.s and then in the late 1970's a third summer (May–June) crop was also included. Wheat — green gram (or cowpea) — pearl millet is such a three-crops-a-year multiple cropping system. Phosphate is the costliest major plant nutrient in India and farmers following multiple cropping systems are keen to know the way the phosphate should be apportioned to different crops in a cropping system particularly when small amounts of P are applied. Such information can come only from long-term P fertilization experiments [3, 4]. The objective of the present experiment on a wheat-green gram (or cowpea) — pearl millet multiple cropping system was to study the direct and residual effects of P applied to one crop on the other crops grown in succession and to find the best possible way in which a limited amount of P could be apportioned between the different crops in the rotation. An attempt has also been made to work out the P balance in soil.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 8 (1985), S. 97-100 
    ISSN: 1573-0867
    Schlagwort(e): critical level ; wheat ; zinc
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Studies were conducted in ten non-calcareous arid brown soils (India) to determine the critical level of soil Zn for predicting response of wheat to zinc fertilization. The per cent mean response at 5 mg kg−1 added Zn varied from 1.3 to 51.4 with a mean value of 17.5 per cent over control in terms of grain yield (g pot−1). Further, Zn application resulted in significant increase in Zn concentration in various plant parts in all the soils irrespective of the initial Zn status. The critical level of Zn in soil and plant below which response to applied Zn may be expected was found to be 1.75 mg kg−1 for 0.1 N HC1 extractable soil Zn and 1.7 mg kg−1 for plant tissue Zn.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 73
    Digitale Medien
    Digitale Medien
    Springer
    Plant growth regulation 7 (1988), S. 3-17 
    ISSN: 1573-5087
    Schlagwort(e): Abscisic acid (ABA) content ; barley ; genetic variation ; grain weight ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Two genetically related wheat lines growing in cabinets were given different temperatures during grain filling, and abscisic acid (ABA) was measured in whole grains by gas chromatography with an electron-capture detector. Three genetically related barley lines grown in the field were assayed for ABA content in endosperm and embryo fractions separately by radiommunoassay. Maximum grain growth rate and final weight per grain of the two wheat lines differed by 50–60% at low temperature and 30–40% at high temperature. During grain development two peaks in ABA level were observed at low temperature but only one at high temperature. At times when differences in grain growth rate between genotypes and between temperature treatments were large, the corresponding differences in ABA concentration were small. In barley, one line (Iabo 14) had 30% heavier grains than the other two (Onice and Opale). Endosperm ABA concentrations showed no clear differences between genotypes until grain filling was nearly complete. Embryo ABA levels were up to 10-times greater than those in the endosperm, with Opale having significantly less ABA in the embryo than the other two cultivars. Our experiments did not provide evidence for a causal relationship between ABA levels during grain filling and grain growth rate or final weight.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 74
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 38 (1988), S. 93-100 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; breeding ; preharvest sprouting ; heritability ; variation ; α-amylase ; falling number
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Preharvest sprouting resistance is a major breeding criterion in many regions where white wheat (Triticum aestivum L.) is produced. Availability of genetic sources of sprouting resistance should significantly advance this goal. Objectives of the present investigation were to determine heritabilities and genetic variation of sprouting resistance in progeny of six susceptible genotypes and Clark's Cream, a cultivar with excellent sprouting resistance. Sixty-five randomly selected F2:F3 lines from the six parental combinations were evaluated in blocks-within-replication designs at two locations during 1984–85. Falling number, α-amylase activity, and sprouting percentage in simulated rain were usually more favorable in F2:F4 grain than in grain of the susceptible parents and frequently equalled levels in grain of the resistant parent. Broad sense heritability estimates were moderate to high for falling number and α-amylase activity, low to moderate for visual sprouting, and inconsistent for embryo germination in ABA. Phenotypic correlations with sprouting were significant most often for falling number and least often for the agronomic traits, days to heading and kernel weight. We concluded that increased preharvest sprouting resistance is an attainable objective when genetic sources of strong resistance and appropriate selection criteria, such as sprouting after simulated rain, are used.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 39 (1988), S. 161-166 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; dormancy ; gibberellic acid ; pre-harvest sprouting
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Gibberellic acid, cold (4°C) and a combination of these two treatments were tested for use in breaking dormancy in 27 lines of white-grained wheat with varying levels of resistance to pre-harvest sprouting. Germination increased in all lines treated with gibberellic acid. Dormancy could be broken with 1 μM gibberellic acid. Response to cold varied. A combination of gibberellic acid and cold treatment was the most effective. This technique has been found useful in treating seed in a breeding program aimed at producing wheats with resistance to pre-harvest sprouting.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 39 (1988), S. 7-25 
    ISSN: 1573-5060
    Schlagwort(e): Hordeum vulgare ; barley ; Triticum aestivum ; wheat ; cytogenetics ; chromosome identification ; gene localisation ; interspecific gene transfer ; chromosome elimination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Achievements and limitations regarding three aspects of cytogenetic research in barley and common wheat are illustrated and discussed. Unambiguous chromosome identification has become possible through the application of chromosome banding techniques, mainly C-banding, N-banding and Ag-banding. Gene localisation studies have yielded a vast amount of information regarding the genetic architecture of barley and wheat. Many genes have been allocated to specific chromosomes, and linkage studies have been carried out with some of these genes. There is growing evidence for a considerable discrepancy between distances on the genetic linkage maps and the physical maps of barley and wheat chromosomes. Although barley can be hybridised with most species of the genus Hordeum and with several species of related genera, interspecific gene transfer is very rare and barley breeding can presently make use of the gene pool of only one wild species, viz. H. vulgare ssp. spontaneum. For wheat breeding, the gene pools of species of the genus Triticum and species of related genera are accessible. Several methods have been developed to achieve gene transfer. Genome interactions in interspecific hybrids result in spatial separation of the parental genomes, in nucleolar competition, and sometimes in chromosome elimination and the formation of haploids.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 38 (1988), S. 85-92 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; preharvest sprouting ; dormancy ; α-amylase ; falling number ; inhibitors ; embryo response
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Resistance to preharvest sprouting has been observed in several white wheat (Triticum aestivum L.) genotypes, but the mode of resistance has not been determined. Studies were conducted to characterize the strong preharvest sprouting resistance in Clark's Cream genotype to facilitate breeding for the trait. Clark's Cream and five other hard red and white wheat genotypes were grown in the glasshouse and field and effects of simulated rain, embryo maturity, inhibitors in floral parts and GA, endogenous inhibitors, and ABA and GA combinations on sprouting were measured. The six genotypes differed significantly in sprouting after simulated rain, α-amylase activity, and response to GA and ABA. Embryo maturity and inhibition levels in floral parts and caryopses were nearly similar for all genotypes. Clark's Cream appeared to differ most in high embryo sensitivity, which was fairly nonspecific for ABA, GA, and endogenous inhibitor, and in low α-amylase production during sprouting. Breeding procedures that lead to the preharvest sprouting resistance of Clark's Cream are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 38 (1988), S. 105-111 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; tillering ; heritability ; gene effects ; epistasis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Effective utilization of uniculm wheat (Triticum aestivum L.) germplasm in breeding programs requires an understanding of the inheritance of the uniculm character. The parents, F1, F2, and first generation backcrosses (B1 and B2) of two crosses, each utilizing a uniculm spring wheat line and a locally adapted winter wheat cultivar, were space planted in an experiment to acquire information regarding the genetic control of culm number. Significant F1 deviations from midparent values revealed the presence of substantial non-additive gene effects. The scaling tests of Mather and the joint scaling test detected the presence of epistasis. Hayman's six-parameter model revealed that a negative dominance effect provided the major contribution to variation in culm number, while additive x additive and dominance x dominance gene effects were of considerable importance.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 79
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; grain yield ; selection ; simple mass selection ; gridded mass selection ; rhombic grid selection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary An experiment was conducted in Winnipeg, Manitoba, Canada to: (1) ascertain the efficiency of gridded mass selection; (2) to determine if additional selection efficiency can be achieved through refinement of the gridded mass selection procedure; and (3) to determine if the degree of homozygosity has an effect on response to single-plant selection. Three selection methods [simple mass selection (SMS); gridded mass selection (GMS); and a new rhombic grid selection (RGS)] were applied to four populations [a conventional F2 (CON-F2); an intermated F2 (INT-F2); and 2 partial backcrossed populations] developed from a biparental cross involving the Canadian spring wheat cultivars, ‘Glenlea’ and ‘Sinton’. Averaged over the 4 populations, a single cycle of RGS (10% selection intensity) increased yield by about 9.5%, whereas GMS and SMS increased yield by approximately 4.5% and 3.1%, respectively. The degree of homozygosity of individual plants that make up the population appeared to have an effect on the efficiency of selection. In general, selection was more efficient in the two partial backcrossed populations, and least efficient in the CON-F2 and INT-F2 populations. The largest response to selection (15.9%) was attained when RGS was applied in the backcross to Glenlea population, and the lowest response (1.2%) when SMS was enforced in the CON-F2 population. This paper represents the first report on the efficiency of rhombic grid selection for yield improvement in cereal crops.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 80
    ISSN: 1573-5036
    Schlagwort(e): Gaeumannomyces graminis var.tritici ; rye grass ; Trichoderma hamatum ; T. harzianum ; T. koningii ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Trichoderma hamatum, T. harzianum andT. koningii were isolated from wheat and rye-grass roots from a field in Western Australia. Frequency of occurrence ofTrichoderma spp. was higher on roots subjected to washing only, for both wheat and rye-grass than the roots which were surface-sterilized with 0.6% or 1.25% NaOCl.Trichoderma spp. were recovered at a higher frequency on PDA amended with lactic acid (pH 4.5) than on PDA alone (pH 5.6) or PDA with streptomycin. In general,Trichoderma spp. were isolated at a higher frequency from roots of wheat than that of rye-grass.T. hamatum occurred at a higher frequency in rye-grass roots than in wheat, whereasT. harzianum was more common in roots of wheat than in rye-grass, especially in seedling and milky ripe stages.T. koningii was recovered at a higher frequency from roots at seedling stage of rye-grass than wheat, the reverse being true at tillering stage.T. koningii was not recovered from roots of either host in any sampling when they were surface sterilized with 1.25% NaOCl. The take-all fungus was isolated from wheat and rye-grass roots more frequently at tillering and stem extension stages than others. It was severely pathogenic to both hosts in sterilized and non-sterilized soil. Addition of lactic acid, HCl or streptomycin to PDA did not affect the growth of theTrichoderma spp. tested, but the growth was slower on Martin's medium than on other media. In generalT. harzianum andT. koningii grow faster thanT. hamatum. The growth of the three species were not different at 20 and 25°C, but at 15°c growing of all species was significantly reduced. Incorporation of lactic acid into PDA prevented the bacterial growth in all treatments. Streptomycin too reduced but to a lesser degree than lactic acid. Surface sterilization with NaOCl decreased the recovery of both bacteria and fungi. T. hamatum andT. koningii reduced the mortality of wheat and rye-grass plants inoculated with the take-all fungus in sterilized and non-sterilized soil, whereT. harzianum did not protect wheat or rye-grass from infection by the take-all fungus.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 81
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 109 (1988), S. 263-269 
    ISSN: 1573-5036
    Schlagwort(e): peas ; plant genetics ; plant growth ; Pseudomonas ; rhizosphere bacteria ; Serratia ; symptoms ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Spring wheat (Triticum aestivum L.) and pea (Pisum spp.) genotypes were tested for reaction to root inoculation with rhizosphere bacteria affecting plant growth. Plant response was studied in greenhouse experiments after treatment of seedlings with bacteria suspended in nutrient broth. Significant genotype variation was found in both wheat and pea in terms of shoot dry weight and severity of bacteria-induced leaf symptoms. For most bacterial isolates tested, there was good correlation between ratings of leaf symptoms 7 to 14 days after inoculation and growth inhibition measured after four weeks. Interactions between isolates and plant genotypes were significant in both wheat and pea (P=0.0024 and 0.0001, respectively), but genotypes with sensitivity or tolerance to most isolates could be distinguished. In an outdoor pot experiment, two of the bacterial isolates caused delayed plant development and differential decreases in grain yield of wheat genotypes. The hypothesis that the reaction of wheat genotypes to the tested becteria was related to their influence on bacterial establishment in the rhizosphere could not be substantiated.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 20 (1985), S. 587-590 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Ion-pair chromatography ; Sulfonate pairing ion ; Adsorption isotherms
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The retention of positively and negatively charged and neutral solutes was studied in an aqueous phosphate buffer eluent, with constant inorganic-counterion concentration, on ODS-Hypersil stationary phase in the presence of various sulfonic acid ion-pairing reagents. The adsorption isotherms of the ion-pairing reagents d-camphor-10-sulfonic acid, sodium cyclohexylsulfamic acid and sodium alkylsulfonates (butyl-, hexyl- and octyl-) were determined by the breakthrough method.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 83
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 20 (1985), S. 615-617 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Vitamin B2 in food ; Column switching ; Liquid-solid extraction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Vitamin B2 was enriched by liquid-solid extraction from large volumes of aqueous samples on a short precolumn. The enriched compounds were transferred onto an analytical reversed-phase column and separated by ion-pair chromatography. The equipment used provides the possibility of automation for routine analysis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 84
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Controlled-porosity glasses ; Chemically bonded phases ; Boron-glass surface enriched
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary In the preparation of C18-bonded phases higher coverage densities were obtained using dimethylaminodimethyl-n-octadecylsilane than chlorodimethyl-n-octadecylsilane as the reagents. The HPLC results show the very high hydrophobicity of the materials obtained. The elution mechanism has been found to be independent of the coverage density on the boron-enriched glass surface in the range 2.3–4.0 μmol/m2.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 85
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Direct injection of biological samples ; New quinitidine metabolites ; Deproteinisation on precolumn ; Column switching
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary New quinidine metabolites, including 10,11-dihydrodiol quinidine N-oxide, 10,11-dihydrodiol quinidine and their glucuronides, were found in human urine. A quinidine monitoring HPLC method including these metabolites, is proposed by the direct injection of body fluid samples onto the precolumn for deproteinization followed by reverse phase separation in the analytical column with a column switching technique. The recovery of spiked quinidine and its metabolites in plasma was quantitative (98–102%) with good reproducibility (C.V.: 1.6–4.0%). Several clinical samples such as whole blood and urine were analyzed by the present method.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 86
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Quantitative structure-retention relationships (QSRR) ; CNDO/2-MO Calculations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Retention data for 12 aromatic test solutes with functional groups of various polarities were studied on a wellcharacterized monomeric octadecyl stationary phase over a range of methanol/water compositions. CNDO calculations on the solute structures and regression analysis indicated that two terms, the total energy, ET, and the maximal difference of electron excess charge, Cd, correlated well with changes in retention as a function of methanol composition. This approach allowed for the non-empirical calculation of retention data for solutes with a range of polarities, overcoming previous deficiencies in the estimation of molecular polarity for non-homologous solutes based on total dipole moment.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 87
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Weak cation-exchanger ; Styrene-divinylbenzene copolymer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A weak cation-exchanger for high-performance liquid chromatography is obtained by oxidation of either poly(methylstyrene-divinylbenzene) or of poly(chloromethylstyrene-divinylbenzene). Reaction conditions were optimised to yield an exchange capacity of about 4meqg−1 dry resin. The material was evaluated chromatographically as a function of pH, organic modifier, temperature and flow rate. A combination of ionexchange and hydrophobic interaction between the solutes and the packing material was observed. This could be used to provide more options for realising chromatographic separations. Some chromatograms of heterocyclic bases, nucleosides, nucleotides and amino acids are shown.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 20 (1985), S. 87-96 
    ISSN: 1612-1112
    Schlagwort(e): Time Optimization ; Column liquid chromatography ; Microbore ; Theophylline
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Algorithms for the time optimization of an HPLC separation are presented. Resolution, column performance, extra-column variance, capacity factor, and column length are incorporated into these algorithms. Extracolumn variance for a high-speed microbore system (1 mm i. d. column) was assessed using 2nd moment variance and a non-linear extrapolation of tubing length to zero. Extra-column variance, as a function of flowrate, was incorporated into the reduced operating curve of column performance. The use of empirical correction factors for column reproducibility and homogeneity are suggested. Cutting to an optimum length did not degrade column performance. These algorithms were applied to the optimization of a microbore assay for theophylline, in a simple xanthine mixture. Resulting total analysis times were reduced to 10seconds per sample, at a flowrate of 700μl/min.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 89
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 20 (1985), S. 72-74 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Metal complexes ; Tetrakis(4-methylphenyl)porphine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The feasibility of reversed-phase high-performance liquid chromatography for the separation of several metal complexes ofmeso-tetrakis(p-tolyl)porphine (TTP) is described. A combination of an octadecyl-bonded stationary phase with a non-aqueous polar mobile phase, such as an acetone-acetonitrile mixture, has proved effective for the separation. Thus, the TTP complexes of Mg, VO, Ni, Cu, Zn, and Pd and also TTP free acid were successfully separated in about 10min on a Li-Chrosorb RP-18 column (7μm, 250×4mm i.d.) with a 70∶30 (vol/vol) mixture of acetone and acetonitrile at a flow-rate of 1 mlmin−1.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 265-271 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Chiral phases ; Polymer coating ; Quinine substituted polysiloxanes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Stationary phases for chiral separations have been synthesized by chemical modification of porous small particle silica using new procedures of fixation of the chiral moiety. So called pre-polymers of the methylpolysiloxane polysiloxane type are immobilized on silica surfaces by different procedures. These pre-polymers are substituted by chiral groups. Their synthesis is done externally i.e. not in-situ on the support surface. The immobilization on the silica surface is achieved by crosslinking and/or by chemical bonding. Anchor groups within the pre-polymer (e.g. SiH) as well as on the silica surface (SiOH) give rise to the chemical bonding therewith. Chiral phases with quinine as the chiral moiety were obtained which show high separation efficiency as well as chemical stability, in addition to the enantiomeric selectivity required for the separation of certain types of aliphatic and aromatic alcohols.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 91
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 288-294 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Mobile phase volume ; Ionic solutes ; Eluent electrolyte
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A new method for the determination of the mobile phase volume (V m) in liquid chromatography is presented based on the model regarding the retention of ionic solutes in the presence of eluent electrolytes. TheV m value can be determined by measuring the retention volumes of two ions that have the same charge in two eluent electrolyte systems. Compared with the methods using isotopically labelled eluent components or inorganic salts asV m markers, the method presented is proved to give more reasonableV m values for both normal and reversed-phase liquid chromatography. As well as in binary mixed solvent systems, theV m values in single solvent systems can be determined by this method.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 92
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 339-342 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Gradient elution ; Prediction of retention
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A general equation for the final retention of a solute chromatographed under conditions of stepwise gradient elution has been derived. The elution process and the distances travelled by solutes as a function of eluent volume were simulated by computer for the optimization of stepwise gradient prorams from isocratic HPLC data. The validity of the equations was experimentally veritied.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 93
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 272-278 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Polyaromatic hydrocarbons ; Molecular parameters ; Retention prediction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The present research studies the possibility of using the correlation dependence between molecular parameters of unsubstituted polyaromatic hydrocarbons (PAH) and their retention in reversed-phase liquid chromatography to optimize the conditions for the separation and identification of unknown peaks on the chromatograms of multicomponent mixtures. A linear correlation equation, that takes the number and environment of the carbon atom in the PAH molecule into account as well as the differences in the specific interactions of isomeric molecules with polar eluent, has been proposed. The adequacy of the proposed PAH retention model was verified by comparing the calculated retention values with the experimental data. The possibility of identifying unsubstituted PAH according to the number of carbon atoms of various types and according to the values of the molecules lengths (calculated on the basis of the retention of these substances under different eluent compositions) was exemplified by various chromatographic systems (reversed phase-eluent-PAH molecules).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 327-331 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Olefin group selectivity ; Methylene group selectivity ; Non-aqueous reversed-phase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The effects of mobile phase composition upon olefin group selectivity (the ratio of the retention factor of a n-alkane to 1-olefin of equal carbon number) has been examined for non-aqueous reversed-phase liquid chromatorphy. Under time-normalized conditions, large variations in olefin group selectivities were noted as the mobile phase constitutents were changes. However, methylene group selectivities were found to be insensitive to the nature of the mobile phase under these conditions. Mobile phases containing alcohols demonstrated low olefin group selectivities compared to those containing acetonitrile as weak solvent. The results of this study explain variations previously observed in the LC separation of olive oil triglycerides that differ in the number of methylene groups and double bonds.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 419-422 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Cyano bonded phases ; Residual silanol groups ; Diethyldithiocarbamates
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary When a cyano bonded phase is used together with a nonaqueous eluent, it is universal that the silanol groups which remain at the surface of the silica gel after bonding affect the retention of solutes. With solutes containing such atoms as N, S and O, hydrogen bond may form between the solute and the residual silanol group, leading to dual retention mechanism. Based on the understanding of retention mechanism, methods were developed to separate metal-diethyldithiocarbamate (DDTC) chelates and crown ethers on cyano bonded phase, the mobile phase being a nonaqueous solvent containing triethylamine (TEA).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 96
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 409-412 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Separation of proteins ; Biological activity after separation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The proteins of the large ribosomal subunit fromEscherichia coli have been separated by size-exclusion, ion-exchange and reversed-phase high-performance-liquid chromatography (HPLC) using various buffer systems. The biological activity of the isolated proteins was tested via their ability to assemble into active 50S subunits (total reconstitution). The activity of the reconstituted subunits was measured with poly(U)-dependent poly-(Phe) synthesis. Reversed-phase HPLC techniques yielded active proteins (80–100%) by application of 2-propanol or acetonitrile. Proteins prepared by size-exclusion chromatography employing ammonium acetate as buffer also gave highly active proteins (70%). On the other hand, separation of the proteins on ion-exchange columns, using urea containing buffers, resulted in reduced activity (up to 50%).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 97
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Phospholipids ; Amniotic fluid ; Fetal lung maturity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A new quantitative analytical method for the determination of phospholipids in amniotic fluid by high performance liquid chromatography (HPLC) is described. In addition to the main compounds, phosphatidylcholine (lecithin) and sphingomyelin, the so-called minor phospholipids, phosphatidylglycerol, phosphatidylinositol and phosphatidylethanolamine can also be determined. Separation is achieved using a guard-column of Lichrosorb Si 60 and an analytical column of Lichrosorb DIOL. Acetonitrile/water is used as mobile phase at an elevated temperature. By determining the recovery rates, the within-run and the between-run precision, it was shown that sufficient accuracy and precision could be achieved for all the parameters examined. The method is highly sensitive, the detection limit for sphingomyelin is 0.2 μg and 0.1 μg for all the other components. A single determination of 5 phospholipids in an amniotic fluid sample takes about two hours. By performing simultaneous extractions it is possible to analyse 5 samples per day.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 98
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Reversed-phase diphenyl and naphtylethyl bonded phases ; Retention/molecular polarizability relationships ; Peropyrene aromatics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The retention behavior of 15 peropyrene-type polycyclic aromatic hydrocarbons was investigated on various bonded stationary phases in reversed-phase liquid chromatography. On diphenyl and naphthylethyl bonded phases, high correlations were obtained between the molecular polarizability of solutes and their retention. However, very low or no correlations were found on various octadecyl bonded phases. These facts are discussed by using the electrostatic interaction concept between the solutes and the stationary phase. We conclude that these observations are due to two reasons: the difference in the degree of planarity of polycyclic aromatic hydrocarbons and the high ability of planarity recognition of octadecyl bonded phases.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 99
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 504-506 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Porous polymeric sorbent ; Solid-phase extraction ; Chlorophenols
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A new porous polymer obtained by the copolymerization of two cross-linking agents: 1,4-di(methacryloyloxymethyl) naphthalene and divinylbenzene was used for the off-line preconcentration of chlorophenols from water solutions by solid-phase extraction. In order to establish its applicability to preconcentration the recoveries and breakthrough volumes of phenol, 2-; 3-chlorophenols; 2,3-; 2,4-dichlorophenols and 2,4,6-trichlorophenols were studied. The recoveries of the studied compounds were compared with those obtained for chemically bonded phases containing hexyl and octadecyl groups.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 515-519 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Retention/structure relationships ; Retention prediction ; Substituted phenols
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A retention prediction system (RPS) for substituted phenols in reversed-phase HPLC using a ternary mobile phase was investigated. The RPS was used to predict the retention times of the phenols, and then evaluated by comparing measured and predicted retention data. Excellent agreement between both values was obtained. In addition, the retention mechanism of the phenols was investigated by means of a correlation analysis relating the parameters of the RPS to the physicochemical properties of the phenols. The three properties investigated (partition coefficient, hydrophobic substituent constant and Hammett's constant) were used to describe quantitatively the structure-retention relationship. Significant correlating equations between these descriptors and the retention data were obtained.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...