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  • Nitrogen fixation  (53)
  • Gas chromatography  (43)
  • Springer  (96)
  • Cambridge University Press
  • Nature Publishing Group
  • 1980-1984  (96)
  • 1975-1979
  • 1984  (51)
  • 1981  (45)
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  • Springer  (96)
  • Cambridge University Press
  • Nature Publishing Group
  • Wiley-Blackwell  (111)
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  • 1980-1984  (96)
  • 1975-1979
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  • 1
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    Springer
    Journal of molecular evolution 21 (1984), S. 19-32 
    ISSN: 1432-1432
    Keywords: Leghemoglobin ; Gene duplication ; Gene linkage ; Concerted evolution ; Nitrogen fixation ; Soybean
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have analyzed the sequences of soybean leghemoglobin genes as an initial step toward understanding their mode of evolution. Alignment of the sequences of plant globin genes with those of animals reveals that (i) based on the proportion of nucleotide substitutions that have occurred at the first, second, and third codon positions, the time of divergence of plant and animal globin gene families appears to be extremely remote (between 900 million and 1.4 billion years ago, if one assumes constancy of evolutionary rate in both the plant and animal lineages) and (ii) in addition to the normal regulatory sequences on the 5′ end, an approximately 30-base-pair sequence, specific to globin genes, that surrounds the cap site is conserved between the plant and animal globin genes. Comparison of the leghemoglobin sequences with one another shows that (i) the relative amount of sequence divergence in various coding and noncoding regions is roughly similar to that found for animal globin genes and (ii) as in animal globin genes, the positions of insertions and deletions in the intervening sequences often coincide with the locations of direct repeats. Thus, the mode of evolution of the plant globin genes appears to resemble, in many ways, that of their animal counterparts. We contrast the overall intergenic organization of the plant globin genes with that of animal genes, and discuss the possibility of the concerted evolution of the leghemoglobin genes.
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  • 2
    ISSN: 1432-2048
    Keywords: Ammonia ; Nitrogen fixation ; Nodule ; Senescence (root nodules) ; Ureide ; Vigna
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During early development (up to 18 d after sowing) of nodules of an “effective” cowpea symbiosis (Vigna unguiculata (L.) Walp cv. Vita 3: Rhizobium strain CB756), rapidly increasing nitrogenase (EC 1.7.99.2) activity and leghaemoglobin content were accompanied by rapid increases in activities of glutamine synthetase (EC 6.3.1.2), glutamate synthase (EC 2.6.1.53), enzymes of denovo purine synthesis (forming inosine monophosphate) xanthine oxidoreductase (EC 1.2.3.2), urate oxidase (EC 1.7.3.3), phosphoenolpyruvate carboxylase (EC 4.1.1.31) and led to increased export of ureides (allantoin and allantoic acid) to the shoot of the host plant in the xylem. Culturing plants with the nodulated root systems maintained in the absence of N2 (in 80 Ar: 20 O2, v/v) had little effect on the rates of induction and increase in nitrogenase activity and leghaemoglobin content but, in the absence of N2 fixation and consequent ammonia production by bacteroids, there was no stimulation of activity of enzymes of ammonia assimilation or of the synthesis of purines or ureides. Addition of NO 3 - (0.1–0.2 mM) relieved host-plant nitrogen deficiency caused by the Ar: O2 treatment but failed to increase levels of enzymes of N metabolism in either the bacteroid or the plant-cell fractions of the nodule. Premature senescence in Ar: O2-grown nodules occurred at 18–20 d after sowing, and resulted in reduced levels of nitrogenase activity and leghaemoglobin but increased the activity of hydroxybutyrate oxidoreductase (EC 1.1.1.30).
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  • 3
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    Planta 152 (1981), S. 544-552 
    ISSN: 1432-2048
    Keywords: Ammonium assimilation ; Lichens ; Nitrogen fixation ; Peltigera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Nostoc in the cephalodia of the lichen Peltigera aphthosa Willd. fixed 15N2 and the bulk of the nitrogen fixed was continuously transferred from it to its eukaryotic partners (a fungus and a green alga, Coccomyxa sp.). Kinetic studies carried out over the first 30 min, after exposure of isolated cephalodia to 15N2, showed that highest initial 15N2-labelling was into NH 4 + . After 12 min little further increase in the NH 4 + label occurred while that in the amide group of glutamine and in glutamate continued to increase. The 15N-labelling of the amino group of glutamine and of aspartate increased more slowly, followed by an increase in the labelling of alanine. When total incorporation of 15N-label was calculated, the overall pattern was found to be rather similar except that, throughout the experiment, the total 15N incorporated into glutamate was about six times greater than that into the amide group of glutamine. Pulse chase experiments, in which 14N2 was added to cephalodia previously exposed to 15N2, showed that the NH 4 + pool rapidly became depleted of 15N-label, followed by decreases in the labelling of glutamate, the amide group of glutamine and aspartate. The 15N-labelling of alanine, however, continued to increase for a period. When isolated cephalodia were treated with L-methionine-SR-sulphoximine, an inhibitor of glutamine synthetase (EC 6.3.1.2), and azaserine, an inhibitor of glutamate synthase (EC 2.6.1.53), there was no detectable labelling in glutamine although the 15N-labelling of glutamate increased unimpaired. On treating the cephalodia with amino-oxyacetate, an inhibitor of aminotransferase activity, the alanine pool decreased. Evidence was obtained that glutamine synthetase and glutamate synthase were located in the Nostoc, and that glutamate dehydrogenase (EC 1.4.1.4) and various amino-transferases were located in the cephalodial fungus. Possible implications of these findings are discussed.
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  • 4
    ISSN: 1432-072X
    Keywords: Nitrogen fixation ; Regulation ; Guanosine 5′-diphosphate 3′-diphosphate (ppGpp)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Addition of ammonium to N2 fixing cultures of Azotobacter vinelandii, Klebsiella pneumoniae and Clostridium pasteurianum rapidly reduced the intracellular levels of guanosine 5′-diphosphate 3′-diphosphate (ppGpp) by 70–90%. This change might reflect a regulatory role of ppGpp in nitrogen metabolism.
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  • 5
    ISSN: 1432-072X
    Keywords: Ammonium export ; Ammonium assimilation ; Glutamine synthetase ; Nitrogen fixation ; Rhizobium sp. 32H1
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relationship between ammonium assimilation and ammonium export has been studied in free-living, N2-fixing Rhizobium sp. 32H1. After 55 to 67 h of microaerobic growth under a gas phase of 0.2% O2 – 1.0% CO2 – 98.8% Ar high levels of nitrogenase were observed concomitant with a slightly adenylylated glutamine synthetase (GSI) and some glutamine synthetase (GSII) activity. However, after growth of 89 h, or longer, GSI became adenylylated and the level of GSII had decreased. When the gas phase was shifted to 0.2% O2 – 1.0% CO2 – 98.8% N2, a lag was observed before ammonium export could be detected in the 55 to 67 h cultures. No lag in ammonium export was observed in the cultures previously grown for 89 h. The onset of ammonium export in the 55 to 67 h cultures was found to correlate with the adenylylation state of GSI. There appeared to be no correlation between the level of GSII and the export of ammonium. Neither an increase in the adenylylation level of GSI nor ammonium export was observed when the 55 to 67 h cultures were maintained under the Ar gas mixture.
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  • 6
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    Archives of microbiology 129 (1981), S. 238-239 
    ISSN: 1432-072X
    Keywords: Rhizobium ; Disaccharide ; Bacteroid ; Transport ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Slow growing strains of rhizobia appear to lack both uptake systems and catabolic enzymes for disaccharides. In the fast-growing strains of rhizobia there are uptake mechanisms and catabolic enzymes for disaccharide metabolism. In Rhizobium leguminosarum WU 163 and WU235 and R. trifolii WU290, sucrose and maltose uptake appears to be constitutive whereas in R. meliloti WU60 and in cowpea Rhizobium NGR234 uptake of these disaccharides is inducible. There is evidence that there are at least two distinct disaccharide uptake systems in fast-growing rhizobia, one transporting sucrose, maltose and trehalose and the other, lactose. Disaccharide uptake is via an active process since uptake is inhibited by azide, dinitrophenol and carbonyl cyanide m-chlorophenylhydrazone but not by arsenate. Bacteroids of R. leguminosarum WU235 and R. lupini WU8 are unable to accumulate disaccharides.
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  • 7
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    Archives of microbiology 130 (1981), S. 38-43 
    ISSN: 1432-072X
    Keywords: Nitrogen fixation ; Gene expression ; Regulation ; Messenger RNA ; Transcription ; Klebsiella pneumoniae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrogenase messenger RNA synthesis in Klebsiella pneumoniae was determined by labelling cells with (3H)uracil and isolating total RnA, which was then hybridized to filterbound recombinant plasmid pSA30 DNA carrying the nitrogenase structural genes nifH, D, and K. Derepression of nitrogenase mRNA starts 1.5 h before the onset of nitrogenase activity (as measured by acetylene reduction). Exposure of nif-derepressed cultures to either NH 4 + , air, or high temperatures (39° C) results in a rapid decrease of the synthesis rates both of nitrogenase mRNA and nitrogenase polypeptides. Nitrogenase mRNA is remarkably stable. After blocking transcription with rifampicin, hybridizable and actively translatable nitrogenase mRNA survives with an average half-life of 18 min. Half-lives are considerably shorter when rifampicin-inhibited cultures are simultaneously shifted to conditions which are non-permissive for nitrogenase synthesis, pointing to some posttranscriptional influence on nitrogenase mRNA stability. In all experiments performed there was no evidence for uncoupling of nitrogenase mRNA synthesis from nitrogenase mRNA translation, indicating that nitrogenase synthesis is regulated solely by transcriptional control.
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  • 8
    ISSN: 1432-072X
    Keywords: Rhizobium trifolii ; Symbiosis ; Nodulation ; Nitrogen fixation ; Symbiotic genes ; Reiterated sequences ; Plasmid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A Rhizobium trifolii symbiotic plasmid specific gene library was constructed and the physical organisation of regions homologous to nifHDK, nifA and nod genes was determined. These symbiotic gene regions were localised to u 25 kb region on the sym-plasmid, pPN1. In addition four copies of a reiterated sequence were identified on this plasmid, with one copy adjacent to nifH. No rearrangement of these reiterated sequences was observed between R. trifolii bacterial and bacteroid DNA. Analysis of a deletion derivative of pPN1 showed that these sequences were spread over a 110 kb region to the left of nifA.
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  • 9
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    Archives of microbiology 138 (1984), S. 212-216 
    ISSN: 1432-072X
    Keywords: Denitrification ; Nitrate respiration ; Nitrous oxide reduction ; Nitrogen fixation ; Azospirillum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrous oxide reduction can consistently be demonstrated with high activities in cells of Azospirillum brasilense Sp 7 which are grown anaerobically in the presence of low amounts of nitrite. Azospirillum can even grow anaerobically with nitrous oxide in the absence of any other respiratory electron acceptor. Nitrous oxide reduction by Azospirillum is inhibited by acetylene, amytal and weakly by carbon monoxide. Azospirillum converts nitrous oxide to molecular nitrogen without the formation of ammonia. The cells must, therefore, be supplied with ammonia from nitrogen fixation during anaerobic growth with nitrous oxide. When no other nitrogen compound besides nitrous oxide is available in the medium, the bacteria synthesize nitrogenase from protein reserves in about 2 h. Nitrogenase synthesis is blocked by chloramphenicol under these conditions. In contrast, the addition of nitrate or nitrite to the medium represses the synthesis of nitrogenase. Nitrous oxide reduction by Azospirillum and other microorganisms is possibly of ecological significance, because the reaction performed by the bacteria may remove nitrous oxide from soils.
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  • 10
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    Archives of microbiology 130 (1981), S. 96-100 
    ISSN: 1432-072X
    Keywords: Nitrogen fixation ; Nitrate respiration ; Denitrification ; Assimilatory nitrate reduction ; Dissimilatory nitrate reduction ; Acetylene reduction ; Azospirillum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Azospirillum spp. participate in all steps of the nitrogen cycle except nitrification. They can fix molecular nitrogen and perform assimilatory nitrate reduction and nitrate respiration. Culture conditions have been defined under which nitrate is used both as terminal respiratory electron acceptor and as nitrogen source for growth. Nitrate and, possibly to a very limited extent, nitrite, but not sulfate, iron or fumarate support anaerobic respiration. Under anaerobic conditions, nitrate can also supply energy for nitrogen fixation but without supporting growth. Nitrate-dependent nitrogenase activity lasts only for 3–4 h until the enzymes of assimilatory nitrate reduction are synthesized. Nitrite accumulates during this period and inhibits nitrogenase activity at concentrations of about 1 mM.
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  • 11
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    Archives of microbiology 140 (1984), S. 215-217 
    ISSN: 1432-072X
    Keywords: Glutathione reductase ; Cyanobacteria ; Nostoc muscorum ; O2 protection ; Glutathione ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Glutathione reductase activity was detected and characterized in heterocysts and vegetative cells of the cyanobacterium Nostoc muscorum. The activity of the enzyme varied between 50 and 150 nmol reduced glutathione· min-1·mg protein-1, and the apparent Km for NADPH was 0.125 and 0.200 mM for heterocysts and vegetative cells, respectively. The enzyme was found to be sensitive to Zn+2 ions, however, preincubation with oxidized glutathione rendered its resistance to Zn+2 inhibition. Nostoc muscorum filaments were found to contain 0.6–0.7mM glutathione, and it is suggested that glutathione reductase can regenerate reduced glutathione in both cell types. The combined activity of glutathione reductase and isocitrate dehydrogenase in heterocysts was as high as 18 nmol reduced glutathione·min-1·mg protein-1. A relatively high superoxide dismutase activity was found in the two cell types; 34.2 and 64.3 enzyme units·min-1·mg protein-1 in heterocysts and vegetative cells, respectively. We suggest that glutathione reductase plays a role in the protection mechanism which removes oxygen radicals in the N2-fixing cyanobacterium Nostoc muscorum.
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  • 12
    ISSN: 1432-2048
    Keywords: Nitrogen fixation ; Nodule development ; Senescence (nodules) ; Vigna
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cowpea (Vigna unguiculata (L.) Walp cv. Vita 3) seedlings inoculated with Rhizobium strain CB756 were cultured with their root systems maintained in air or in Ar: O2 (80:20, v/v) during early nodule development (up to 24 d after sowing). Compared with those in air, seedlings in Ar:O2 showed progressive N deficiency with inhibited shoot growth, reduced ribulose-1,5-bisphosphate carboxylase and total protein levels and loss of chlorophyll in the leaves. Nodule initiation, differentiation of infected and uninfected nodule tissues and the ultrastructure of bacteriod-containing cells were similar in the air and Ar: O2 treatments up to 16 d after sowing. Thereafter the Ar: O2 treatment caused cessation of growth and development of nodules, reduced protein levels in bacteroids and nodule plant cells, and progressive degeneration of nodule ultrastructure leading to premature senescence of these organs. Provision of NO 3 - (0.1–0.2 mM) to Ar: O2-grown seedlings overcame the abovementioned consequences of N2 deficiency on nodule and plant growth, but merely delayed the degenerative effects of Ar: O2 treatment on nodule structure and senescence. Treatment of Ar: O2-grown seedlings with NO 3 - greatly increased the protein level of nodules but the increase was largely restricted to the plant cell fraction as opposed to the bacteroids. By contrast, NO 3 - treatment of air-grown seedlings increased protein of bacteroid and host nodule fractions to the same relative extents when compared with air-grown plants not supplemented with NO 3 - . These findings, taken together with studies of the distribution of N in nodules of symbiotically effective plants grown from 15N-labeled seed, indicate that direct incorporation of fixation products by bacteroids may be a critical feature in the establishment and continued growth of an effective symbiosis in the cowpea seedling.
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  • 13
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    Chromatographia 14 (1981), S. 19-22 
    ISSN: 1612-1112
    Keywords: Teflon columns ; Chemically modified teflon ; Gas chromatography ; Capillary columns
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Wall-coated open tubular columns prepared from chemically modified teflon tubing have been developed for gas chromatography. Chemical reaction of the inner walls of teflon tubing allows bonding of an adhesive layer on which a variety of stationary phaes can be coated. Test mixtures of alkanes and alcohols were used to investigate the chromatographic properties of these columns and the stability and mixing of the adhesive and stationary phae layers. the results in dicate that mixing of the layers is negligible and that the column is stable for a long period of time.
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  • 14
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    Chromatographia 14 (1981), S. 55-66 
    ISSN: 1612-1112
    Keywords: Capillary columns, glass ; Gas chromatography ; Column preparation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Kapillar-Gas-Chromatographie ist heute das sich am stärksten entwickelnde Gebiet der Gas-Chromatographie. Es gibt viele komplexe, neue Fragestellungen in der Analytik, welche den Einsatz spezieller Kapillarsäulen erfordem. Glücklicherweise gibt es aber auch eine große Zahl von Herstellungsverfahren für Kapillarsäulen, welche — noch mehr als bei der Herstellung von gepackten Säulen — eine Anpassung an die gestellten Aufgaben ermöglichen. In diesem Artikel werden die Herstellungsverfahren für Kapillarsäulen zusammengestellt und Anregungen gegeben, wie aufgaben-orientierte Säulen erreicht werden.
    Notes: Summary Glass capillary column chromatography is the most rapidly growing part of gas chromatography. There are many complex new analytical tasks and they require special capillary columns, Fortunately there is a wide range of column preparation methods available, and they make the preparation of glass capillary columns a more varied job than that of packed columns. In this paper these methods are reviewed and suggestions are given for making task-oriented columns.
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  • 15
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Urea herbicides ; Catalytic hydrolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method is described for the rapid catalytic hydrolysis of phenylurea herbicides on silica gel at elevated temperatures. After derivatisation of the anilines produced with heptafluorobutyric acid anhydride final analysis is done on a gas chromatograph equipped with an electroncapture detector. Detection limits are in the 1–5 picogram range. The method has successfully been applied to residue analysis of water samples at the 1 ppb level. The determination of free anilines present in water samples and the potential of various techniques to be used to discriminate between free anilines and parent herbicides are also discussed.
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  • 16
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Graphitised carbon black ; Phenols ; Water pllutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The fractionation of eleven phenols which may be contaminants in drinking water has been accomplished by using acid-washed graphitised carbon black modified with trimesic acid and PEG 20 M.
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  • 17
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    Chromatographia 14 (1981), S. 447-451 
    ISSN: 1612-1112
    Keywords: Headspace analysis ; Gas chromatography ; Residual analysis of polyethylene terephthalate ; Acetylene reduction assay ; Ethylene evolution in germinating seed ; Acetaldehyde generation in polyester resin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary New application areas for headspace gas chromatography in agricultural and polymer degradation research are described. Specific examples are drawn from the various forms of headspace analysis with emphasis on the automated static equilibrium method.
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  • 18
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Esterification in aqueous solution ; n-Butyl esters of C2−C16 dicarboxylic acids ; Dicarboxylic acid analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary C2−C16 dicarboxylic acids were esterified in aqueous solution in the presence of sulfuric acid. Esterification in water/n-butanol mixtures with mole ratios between 0.02 and 2.53 can be utilized for the quantitative determination of the dicarboxylic acids by gas chromatography. The presence of water does not interfere at water/n-butanol mole ratios below 0.27. For mole ratios above 0.27 anhydrous sodium sulfate has been used for binding the water. The mole ratio range was 0.25–0.75 for anhydrous sodium sulfate/water, and 0.32–1.3 for sulfuric acid/anhydrous sodium sulfate.
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  • 19
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    Chromatographia 18 (1984), S. 663-667 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Gas solubilities ; Enthalpies of solution ; Polar solutions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The gas-liquid chromatographic method has been used to determine the solubilities and partial molar enthalpies of solution of the gases H2S, CO2 and COS in four polar solvents. The results agree well with literature values obtained using conventional techniques, with the one exception of H2S in N-methyl-2-pyrrolidinone. In this case there is some evidence for the occurrence of adsorption at the gas-liquid interface.
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  • 20
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Esterification in aqueous solution ; n-Butyl esters of aromatic polycarboxylic acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The direct esterification and gas chromatographic analysis of aromatic carboxylic acids as n-butyl esters is described. Derivatization is performed in aqueous solution with n-butanol in the presence of sulfuric acid. The butyl esters of benzoic, phthalic, hemimellitic, trimellitic, trimesic and pyromellitic acids permit their gas chromatographic separation from each other and from fatty acids and alipatic dicarboxylic acids. At mole ratios of [H2O]/ [n-BuOH]≤0.04 the water present does not interfere with the esterification reaction. At mole ratios above 0.04 anhydrous sodium sulfate is used for binding the water, at mole ratios of [Na2SO4 anh.]/[H2O]=0.25–0.75.
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  • 21
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    Chromatographia 18 (1984), S. 202-204 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Polysiloxane stationary phases ; Heat of adsorption ; Heat of solution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The changes in the heat of solution of polar compounds and xylene isomers in methylsilicone fluid OV-101 deposited on Chromosorb W AW DMCS were studied. It was shown that the heat of solution increases with an increase of the percentage loading of the OV-101 up to 10%. Solution and adsorption thermodynamic characteristics of the studied system are briefly discussed.
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  • 22
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Metal complexes ; Chemically bonded phase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Packings consisting of diphenylphosphine complexes with CoCl2 and CoBr2, chemically bonded to the silica surface, were synthesized and their retention parameters determined. The packings are capable of specifically interacting with electron-donating compounds by forming π-complexes. The interaction is considerably stronger in the case of CoBr2-containing packing than in the case of CoCl2-containing packing.
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  • 23
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    Chromatographia 18 (1984), S. 234-238 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Open-tubular columns ; On-column injection ; Stopped-flow operation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple, inexpensive, on-column injector of the septum moving-needle kind is described for quantitative analysis using open-tubular columsn. when operated in the stopped-flow mode an improvement incolumn efficiency is observed combined wit a diminished tendency to produce split-top peaks, particularly for late eluting peaks. Using electronic integration a relative error of about 2.7% was observed for peaks spanning a wide range of sample concentrations and volatilities.
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  • 24
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    Chromatographia 18 (1984), S. 243-248 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Carrier gas ; Viscosity ; Influence of temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The vicosity-temperature relationship of the three gases (helium, nitrogen and hydrogen) most frequenly used as the carrier gas in gas chromatography is studied. Based on available data, equaitions are derived to describe this relationship. Using these equations viscosity data are tabulated for the chromatographically important temperature range.
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  • 25
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    Chromatographia 18 (1984), S. 260-264 
    ISSN: 1612-1112
    Keywords: Parabens and their dissolution ; Pharmaceutical dosage forms ; Derivatization ; Gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A specific, sensitive and general applicabla gas chromatographic method is described for the determination of parabens in various liquid pharmaceutical preparations: propylparaben and butylparaben in a liquid antacid dosage form (I); methylparaben, ethylparaben and propylparaben in a syrup (II); methylparaben and propylparaben in a solution for injection (III). Each time one of the parabens is used as internal standard. The parabens are extracted with diethylether and derivatized by silylation. Different columns are used for the analysis of the parabens: 3% SE-30 column, a 3% QF-1 column for different selectivity, a 2% OV-1 column for isothermal operation. Special attention is attributed to the standard: the parabens are dissolved in a minimal amount of 0.1 M sodium hydroxide and extracted in the same way as the pharmaceutical dosage form.
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  • 26
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Configuration ; Resolution ; Alcohols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The study of the resolution of sixteen secondary aliphatic alcohols by gas chromatography on (+)-dodecyl (2R, 3R)-tartrate, trapping the ascending part of the peak from a conventional filled column, has allowed the determination in a single operation of the sign and order of emergence of enantiomers. A correlation between the configuration of these secondary alcohols and their order of emergence has been established.
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  • 27
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    Chromatographia 18 (1984), S. 309-312 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Carboxylic acids ; Acetonyl derivatives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The preparation of the acetonyl esters of nine aliphatic carboxylic acids is described, the general formula of the derivatives being RCOOCH2COCH3 where R=alkyl or H. The derivatives show good chromatographic properties on both packed and capillary columns. The electron impact and chemical ionisation mass spectra of the derivatives are discussed.
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  • 28
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Thermodynamic relationships ; Retention index ; Peak identification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A thermodynamic criterion, ΔQ, is suggested which permits to estimate the difference in the functional group energy of interactions for two different stationary phases. The linear dependence of ΔQ on the homolog number m of any series Rm X can be used as the thermodynamic criterion for the identification of substances by GC analysis.
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  • 29
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    Chromatographia 18 (1984), S. 477-488 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Open tubular (capillary) columns ; Sample capacity ; Column comparison ; Film thickness ; Column diameter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Wall-coated, open-tubular (capillary) columns prepared from different diameter tubing, with different liquid phase film thickness, are compared with each other and with packed and support-coated open-tubular columns. The comparison is based on the variation of the phase ratio and the capacity factor, and includes column efficiency (HETP, theoretical plate number), resolution, retention time, and sample capacity. Problems associated with the evaluation of the sample capacity are outlined. The influence of temperature on column performance is discussed in detail. Finally, the possibilities of short, wide-bore open-tubular columns prepared with a thick liquid-phase film are demonstrated.
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  • 30
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    Plant and soil 59 (1981), S. 201-206 
    ISSN: 1573-5036
    Keywords: Acetylene reduction ; Coffee plantation ; Inga jinicuil ; Nitrogen fixation ; Nodule biomass ; Woody legume
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Nodule biomass and yearly C2H2 reduction rates are reported forInga jinicuil, a leguminous tree used for shade in Mexican coffee plantations. Annual fixation by this species approximates 35 kg ha−1; which, when compared to nitrogen additions from fertilizers, represents an important nitrogen input to the coffee ecosystem.
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  • 31
    ISSN: 1573-5036
    Keywords: Azotobacter vinelandii ; Gnotobiotic cultures ; Nitrogen fixation ; Oryza sativa Rhodopseudomonas capsulata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary An all glass tight growth chamber, entirely sterilizable, has been constructed to carry out axenic and gnotobiotic cultures of rice plants (Oryza sativa L.). When grown in liquid medium and in the absence of combined nitrogen but in the presence of the diazotrophsAzotobacter vinelandii andRhodopseudomonas capsulata, rice plants exhibited a complete biological cycle from germination up to ear stage, during a period of time similar to the one encountered in french paddy soil of Camargue. In one experiment, mannitol was given to rice culture medium together withAzotobacter vinelandii andRhodopseudomonas capsulata. In another experiment, mannitol was not given together with Rhodopseudomonas, and still positive nitrogen gain was obtained, although it was less than culture with mannitol. When15N labeled cells of Rhodopseudomonas were added in rice culture medium,15N was partly transferred to rice plant. Among the nitrogen substances excreted from the bacteria in the rhizosphere medium, large organic molecules were shown to be the most abundant in our experimental conditions. Moreover, the concentration of free ammonia or aminoacids present in the rice rhizosphere were always compatible with a bacterial nitrogenase activity.
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  • 32
    ISSN: 1573-5036
    Keywords: Bacteroids ; Cowpea ; Nitrogen fixation ; Peanut ; Rhizobium ; Siratro
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Acetylene reduction activity and nitrogen accumulation in the plant top per unit nodule mass were compared among peanut, cowpea and siratro plants nodulated by six different strains of Rhizobium. Peanut was found to have several fold higher values than cowpea and siratro for both parameters for all strains of Rhizobium which nodulated it effectively, but the bacteroid content of the peanut nodules was similar to those of cowpea and siratro.
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  • 33
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    Plant and soil 62 (1981), S. 331-336 
    ISSN: 1573-5036
    Keywords: Legumes ; Nitrogen fixation ; 15N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The combination of using15N for determining the amount of nitrogen fixed by a legume crop in field experiments and the labelling of only one treatment at a time in each treatment combination is shown to be conceptually and experimentally valid for determining the effect of cultural practices on the amount of nitrogen fixed by a legume crop.
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  • 34
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    Plant and soil 63 (1981), S. 283-289 
    ISSN: 1573-5036
    Keywords: Afzelia quanzensis ; Brachystegia spiciformis ; Ectomycorrhiza ; Miombo woodland ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Ectomycorrhizae were found in root samples of the treesAfzelia quanzensis Welw. andBrachystegia spiciformis Benth. (Caesalpiniaceae), collected in the coastal miombo type woodland 50 km west of Dar-es-Salaam, Tanzania. Root nodules with a structure resembling that of nitrogen-fixing root nodules of other leguminous plants were observed in theA. quanzensis material. The climate of the locality is rather dry, and strongly seasonal. In the tropics, ectomycorrhizae have previously been found only in humid or rain forest climate zones.
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  • 35
    ISSN: 1573-5036
    Keywords: Actinorhizae ; Alnus nitrida ; Frankia ; Host-specificity ; Nitrogen fixation ; Root nodules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Two different strains, An 1 and An 2, were obtained from root nodules ofAlnus nitida Endl., collected from one locality in the area of its natural habitat near Bahrin, District Swat, Pakistan. The light and electron microscopy of the isolates revealed the occurrence of septate and branched hyphae bearing sporangia and vesicles. The strains differed in their growth requirements, nitrogen-fixing ability and production of extracellular pigments, thus indicating the existence of more than oneFrankia strain in the same locality. In the absence of combined nitrogen in the medium strain An 1 formed vesicles and fixed N2 (up to 200 nmol C2H4. mg protein−1.h−1), while strain An 2 under the experimental conditions formed only few vesicles and fixed N2 at a very low rate (ca 10 nmol C2H4. mg protein−1 .h−1). The nitrogenase activity of strain An 1 was strongly affected by the O2 concentration.Frankia An 1 and An 2 were infective and effective onA. nitida andA. glutinosa but not onDatisca cannabina andElaeagnus umbellata. Both An 1 and An 2 strains were more infective and effective onA. glutinosa thanFrankia strains AvcIl and CpI1.
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  • 36
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    Plant and soil 77 (1984), S. 253-261 
    ISSN: 1573-5036
    Keywords: Acetylene reduction ; Beijerinckia ; Nitrogen fixation ; Paddy ; Phyllosphere ; Silicification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary An investigation was conducted to study the levels of nitrogen fixation on the leaf or sheath surfaces of four cultivars of paddy plants by using acetylene reduction technique. Varying levels of positive nitrogenase activity were observed on all the leaf surfaces. Sheath of IET 1991 cultivar showed a higher rate of fixation than the leaf surface. All the nitrogen-fixing organisms on the leaf or sheath surfaces belonged to the genus Beijerinckia. There was no correlation between the bacterial density and the level of fixation. Scanning electron microscopic data revealed that the upper surface of IET 1991 leaf was highly silicified and the microflora was either scanty or nil while the lower surface appeared quite different and harboured more micro-organisms. Similarly, the inner surface of sheath was devoid of silicification and showed the presence of micro-organisms.
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  • 37
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    Plant and soil 78 (1984), S. 29-43 
    ISSN: 1573-5036
    Keywords: Alnus glutinosa ; Endophyte ; Frankia ; Infectivity ; Nitrogen fixation ; Sporulation ; Variability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Frankia sp. LDAgpl, an isolate from spore positive nodules ofAlnus glutinosa, only slowly infects its host plant. Reisolates obtained from occasional nodules caused by infection with LDAgpl, are capable of infecting the alder much more rapidly. A variability analysis of LDAgpl has been performed to obtain more insight into the question whether these reisolates constitute a different genotype within LDAgpl and if the plant is exerting an influence during plant passage. High dilutions of mildly sonicatedFrankia suspensions were plated to obtain genetically homogeneous colonies. Clones thus generated showed differences in growth pattern, sporulation and C2H2-reduction on media containing propionic acid as sole C-source (P-medium). Differences in sporulation on P-medium indicate that LDAgpl was a highly heterogeneous strain. Comparisons of sporulation on several different media gave evidence that the differences in sporulation between LDAgpl clones are the result of differences in efficiency of propionic acid utilization. The differences observed between the reisolates and LDAgpl clones indicate that the reisolates constitute a different genotype, which could be selected for by the plant during the infection process. Comparison with similar changes in phenotype occuring in a spore negative type strain fromA. glutinosa is discussed.
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  • 38
    ISSN: 1573-5036
    Keywords: Actinorhizas ; Alnus nitida ; Amino acid composition ; Datisca cannabina ; Hydrogen uptake ; Inoculation ; Nitrogen fixation ; Root nodules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The nodulation and the morphology and physiology of the nodules were studied onDatisca cannabina, a perennial herb from northern Pakistan andAlnus nitida, a nodulated tree in the same locality. Both species bear coralloid clusters of actinorhizal nodules. The main free amino acid inD. cannabina nodules was arginine while the predominant free amino acid inA. nitida nodules was citrulline. The infectivity of crushed nodules of both types of plants on their respective host was about 106 infective particles per gram of nodule fresh wt. In cross-inoculation experiments crushed nodule inoculum fromA. nitida failed to induce nodulation onD. cannabina seedlings but the crushed nodule inoculum fromD. cannabina caused low nodulation on seedlings ofA. nitida (103 infective particles. g. nodule fresh wt.). The activity of nitrogenase, hydrogenase and respiration (O2 uptake) were measured in detached nodules, nodule homogenates and the 20 μm residue and 20 μm filtrate preparations from the nodules of both species. Both species showed similar patterns of activities except that only the nodule homogenate and 20 μm residue preparations fromD. cannabina showed pronounced enhancement of the O2 uptake by succinate which was further stimulated by ADP. This has in part been explained by the presence of mitochondria in close connection with the endophyte.
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  • 39
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    Plant and soil 79 (1984), S. 227-234 
    ISSN: 1573-5036
    Keywords: Bacteria ; Inoculation ; Microorganisms ; Nitrogen fixation ; Phosphate solubilization ; Rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Inoculation effect ofA. chroococcum, P. striata andA. awamorii on yield and nutrients uptake in rice was studied under green house conditions. The organisms appreciably increased the yield and uptake of nutrients with or without chemical fertilizers. Phosphorussolubilizing microorganisms and a mixture of the three showed better response than the rest of the treatments among single and mixed culture inoculations respectively. Chemical fertilizers further improved the yield and nutrients uptake. The yield response remained unaffected by replacing superphosphate with rock phosphate and microbial inoculations.
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  • 40
    ISSN: 1573-5036
    Keywords: Mesquite ; Nitrogen fixation ; 15N natural abundance ; Nodule morphology ; Rhizobium bacteria ; Woody legumes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The relative nitrogen fixation efficiencies (RE 1-[H2 evolved÷C2H2 reduced]·100) of four mesquite (Prosopis glandulosa var.torreyana) rhizobia (Strains WR 1001, WR 1002, L5, L9) and a cowpea rhizobia (Strain 176A32) on mesquite were evaluated in a glasshouse experiment. Plant yield, shoot N accumulation, and the natural15N abundance (δ15N) of nodule tissue were determined. Strain WR 1002 failed to nodulate mesquite and strain L5 produced ineffective nodules. Among the three effective strains (WR 1001, L9, 176A32) the cowpea strain (176A32) and strain L9 had significantly higher RE than strain WR 1001. Differences in RE, however, were not accompanied by significantly higher plant yield and shoot N accumulation. The difference in15N abundance between foliar tissue and nodules (nodules minus leaves) was 0.47 δ15N for the ineffective L5 nodules, while for the effective WR 1001, L9, and 176A32 nodules, respectively, this difference was 8.35, 7.81, and 8.35 δ15N. This indicates a similar relationship between N2-fixing effectiveness and natural15N enrichment of nodules that was previously observed in soybeans (Glycine max, L. Merr.). Strains WR 1001 and L9 produced elongate, indeterminate nodules typical for mesquite. The ineffective L5 nodules had few infected cells and an abundance of cortical amyloplasts. Mesquite nodules produced by the cowpea strain were spherical and were somewhat more similar in internal morphology to determinate nodules typical of cowpea than indeterminate nodules normally associated with mesquite.
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  • 41
    ISSN: 1573-5036
    Keywords: Actinorhizae ; Datisca cannabina ; Frankia ; Nitrogen fixation ; Root nodules ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The fine structures of the microsymbiont inside the root nodules ofDatisca cannabina have been studied by light, by transmission- and by scanning-electron microscopy. The endophyte is prokaryotic and actinomycetal in nature. The hyphae are septate and branched, diameter 0.3–0.5 μm. The tips of hyphae are swollen to form electron-dense, clubshaped to filamentous vesicles, ranging in diameter: 0.4–1.4 μm. The endophyte penetrates through walls of the cortial cells. The infected zone is kidney shaped and confined to one side of the acentric stele. The orientation of infection is reversed from other actinorhizae exceptCoriaria. The hyphae are near the host cell wall and vesicles are directed towards the central vacuole. Vesicles are aseptate and no collapsing of the vesicle cell wall (void area) has been observed. Vesicle clusters structures are globular with an opening at one side of the cluster. The host cell is multinucleate or contains a lobed nucleus. Groups of mitochondria are located in between the hyphae, suggesting a strong association between the host and the endophyte for energy supply and amino acid production. The consequences of the inability to separate the mitochondria from the vesicle clusters in nodule homogenates in physiological studies have been discussed. Isolated vesicles clusters showed dehydrogenase activity, indicated by the presence of formazan crystals, after incubation with NADH and NBT. Strongest reducing activity was found within the vesicles. The possible role of filamentous vesicles in nitrogen fixation has been discussed.
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  • 42
    ISSN: 1573-5036
    Keywords: Acetylene reduction ; Actinomycete-nodulated ; Legume ; Lime ; Mine spoil ; Nitrogen fixation ; Reclamation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary An acid mine spoil in Southern Indiana was amended with lime (CaCO3) (0.0, 12.5, 25 and 39t/ha) and planted withElaegnus umbellata Thunb.,Alnus glutinosa Gaertn.,Robinia pseudoacacia L.,Robinia fertilis Ashe, ‘Arnot’,Myrica pensylvania Lois,Caragana arborescens L. andShepherdia argentea Nutt. Survival and soil data were collected periodically and plants were harvested 15 months after planting. Nodule and top dry weights were determined and acetylene reduction assays performed on the nodules. Addition of lime caused significant increases in pH, and 39 t/ha of lime were required to maintain a pH above 5.5. Survival of plant material was greatest at the highest lime addition, although response of individual species varied.Elaeagnus umbellata, R. pseudoacacia, R. fertilis ‘Arnot’, andA. glutinosa appeared more tolerant of the harsh conditions. OnlyC. arborescens showed a linear increase in top dry weight due to lime addition.Alnus glutinosa andS. argentea achieved statistically the same growth regardless of pH, andR. fertilis ‘Arnot’ andE. umbellata did not increase in top dry weight above an addition of 25 t/ha.Robinia pseudoacacia achieved maximum top dry weight at 25 t/ha, whereasM. pensylvanica growth declined with increasing pH. Nodule dry weights increased with increasing pH; however,S. argentea showed greater nodule dry weights at lower lime levels. Acetylene reduction rates increased with lime addition.Elaegnus umbellata did not respond above 25 t/ha lime, whereasA. glutinosa did not show an increase until this point.
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  • 43
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    Plant and soil 77 (1984), S. 3-14 
    ISSN: 1573-5036
    Keywords: Asian-type soybean ; Fast-growingRhizobium japonicum ; Glycine max ; Nitrogen fixation ; Rhizobium japonicum ; Rhizobium physiology ; Root nodule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Physiological and symbiotic characteristics were identified in fast-growing (FG)Rhizobium japonicum. Carbon nutritional patterns linked these rhizobia to other FG rhizobia. They were able to use hexoses, pentoses, disaccharides, trioses, and organic acids for growth, but they were unable to use dulcitol or citrate. These rhizobia produced acid with all carbon sources except intermediates of the Krebs cycle. FGR. japonicum showed no vitamin requirements and were tolerant to 1% NaCl but not to 2%. They nodulated cowpea, pigeon pea, and mung bean but not peanut. Effective, nitrogen-fixing symbioses were observed only with cowpea and pigeon pea. In addition, FGR. japonicum formed effective symbioses with Asian-type soybeans. We concluded that although the physiological characteristics of FGR. japonicum were similar to other FG rhizobia, their symbiotic properties were similar to slow-growing rhizobia of the cowpea miscellany.
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  • 44
    ISSN: 1573-5036
    Keywords: Actinorhizal plants ; Bacterial isolation techniques ; Frankia ; Nitrogen fixation ; Root nodules ; Soil ; Sucrose density fractionation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The isolation and pure culture of the symbiotic nitrogen-fixing frankiae has always been difficult. In the past the isolation of these actinomycetes directly from soil samples has proven impossible and isolations from root nodules of many genera has been only poorly successful. We report here a modified sucrose fractionation procedure which increased the success of isolations from root nodules and which permitted the isolation ofFrankia directly from soil samples. Crushed nodule suspensions or soil suspensions were incubated briefly in 0.7% phenol (carbolic acid) just before application to a sucrose density gradient. This phenol incubation decreased the number of contaminating eubacteria and fungi but more importantly increased the number ofFrankia developing on the isolation plates. If the phenol incubation was used solely without sucrose fractionation noFrankia were isolated, suggesting the death of the organisms due to phenol toxicity. The use of selective nitrogen-deficient media proved important for the isolation of frankiae from soils.
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  • 45
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    Plant and soil 78 (1984), S. 105-128 
    ISSN: 1573-5036
    Keywords: Cytology of root nodules ; Dryas drummondii ; Frankia ; Geographic distribution ; Nitrogen fixation ; Rubus ellipticus ; Ultrastructure of endophyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Root nodules ofDryas drummondii are of the coralloid type (Alnus type). The endophyte is present in the middle cortical cells of the root-nodule tissue. Transmission electron micrographs revealed an actinorhizal endophyte with septate hyphae and non-septate spherical or ovoid vesicles. Vesicles always possess at the base a septum; septa formation in the endophyte is always associated with the presence of mesosomes. Branching of the endophyte is not necessarily correlated with septum formation. Hyphal structures are more prominent in the apical part of the root nodule and vesicles are more numerous in a broad zone below this. In the middle and towards the base of the root nodule the endophytic structures appear in a stage of disintegration. Vesicles appear in a broad region near the periphery of the host cell and regularly show no strict orientation towards the host-cell wall. In the center of the host cells only hyphae occur. In the intercellular spaces between the host cells theFrankia endophyte produces spore-like structures although the outline of the sporangia is often faint. The coralloid root ofRubus ellipticus shows characteristically a basal rootlet initiated below the dichotomous branching of the nodular lobes, but extending beyond the root nodule. The endophyte is only present in the outer cortex of the root nodule in a 1–2 cell wide layer. This endophytic layer is bounded, internally as well as externally, with a 4–5 cell wide layer of tannin-filled host cells. The implications of this situation are discussed. Tannin-filled cells occur regularly inRubus species and their arrangement has been used for taxonomic purposes within the genus. TheRubus endophyte is aFrankia species with septate hyphae and distinctly septate spherical vesicles. The ultrastructure of the vesicles of theRubus endophyte is very similar to that of theAlnus endophyte.
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  • 46
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    Plant and soil 76 (1984), S. 77-91 
    ISSN: 1573-5036
    Keywords: Microorganisms ; Mycorrhizas ; Nitrogen fixation ; Phosphate uptake ; Rhizosphere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary No root systems in nature are without a microbial population. These may be freeliving or symbiotic. The incidence and nutrition of the freeliving microorganisms is discussed. Shortage of substrate makes it unlikely that the N-fixers in the population can fix useful amounts of N. There is a possibility that P supply is improved, but an analysis of possible processes shows them to be rather unlikely, and evidence for them to be poor. Manganese and iron uptake can be altered by microbial activity. Growth of plants can be affected by non-nutritional bacterial effects. The ecology of Rhizobium in the soil is briefly discussed, and the varying needs of different identified strains is stressed. Mycorrhizal infection of plants leads to large growth increases in appropriate conditions. This is almost always linked to increased P uptake, but zinc and copper nutrition can also be improved. The processes involved are briefly discussed. Rapid and extensive infection is important; it is very sensitive to temperature. New modelling methods are now becoming available to measure the behaviour of the fungal infections. The microorganisms require C compounds from the plant, and new measurements of this cost are discussed. The possibility of practical use of mycorrhizal fungi seem to be improving.
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  • 47
    ISSN: 1573-5036
    Keywords: Hill soils ; Lime ; Mycorrhiza ; Nitrogen fixation ; Nodulation ; Phosphorus ; Rhizobium ; Symbioses ; White clover
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The responses of white clover (cv NZ Grasslands Huia grown in four UK hill soil types) to additions of lime and P, to inoculation with Rhizobium and mycorrhizal fungi, and to differences in soil water status were assessed in pot and field experiments. With a deep peat soil in pots, shoot production, nodulation and N fixation by clover were increased by 160, 130 and 85% respectively following inoculation with mycorrhiza, but in the field, despite a doubling of root infection, there was no response in growth. On a brown earth soil in the field inoculation with one endophyte (Glomus mosseae L1) out of four tested depressed production of white clover shoots by 42% but enhanced that of leeks (Allium porrum) by 50%; the others were without effect. With dry peaty podzol and brown earth soils in pots, clover shoot production was highest with added P when a water holding capacity of 80% was maintained, but roots from the latter had only 2.6 compared to 68 nodules per plant from the former. Further work is required to explain poor nodulation in the brown earth soils.
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  • 48
    ISSN: 1573-5036
    Keywords: Acetylene reduction ; Field method ; Medicago sativa L. ; Mucilaginous substances ; Nitrogen fixation ; Trigonella foenum-graecum L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Summary A non-destructive method using a special device for measuringin situ acetylene reducting activity by nitrogen fixing plants is described. Plant roots are isolated from external atmosphere with a mucilaginous material laid on the soil around the plants. Acetylene or ethylene is directly injected into or taken from the soil around the nodules. Using this device the values of acetylene reducing activity ofTrigonella foenum graecum L. andMedicago sativa L. are much higher than those obtained with the same plants placed under polyethylene bags. This method is not expensive and allows the detection of low enzyme activities. It doesn't perturb plant physiology and can be used for young plants as well as for plants with ramified stems at their base.
    Notes: Résumé Les auteurs décrivent un dispositif qui permet de mesurer l'activité nitrogénasein situ par réduction de l'acétylène chez les plantes fixatrices d'azote, sans perturber leur physiologie et sans les détruire. Le système racinaire est isolé de l'atmosphère extérieure par une substance mucilagineuse déposée sur le sol autour des plantes testées. Les gaz acétylène ou éthylène sont injectés ou prélevés directement dans le sol au niveau des nodosités. Avec ce nouveau dispositif les valeurs de l'activité réductrice d'acétylène obtenues surTrigonella foenum-graecum L. etMedicago sativa L. cultivés en plein champ, sont très supérieures à celles mesurées sur ces mêmes végétaux enfermés dans une enceinte en polyéthylène. Cette méthode peu onéreuse, permet de détecter des activités réductrices faibles; elle est utilisable sur des jeunes plantes et également sur des individus ramifiés à la base.
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  • 49
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    Plant and soil 79 (1984), S. 37-49 
    ISSN: 1573-5036
    Keywords: Azotobacter ; Nitrogen fixation ; N2-fixing efficiency ; Respiration ; Soil ; Water potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Respiration and N2-fixation (acetylene reduction) ofAzotobacter vinelandii have been studied at a variety of soil water potentials. Both processes were strictly linked and strongly reduced at water potentials between −0.6 and −1.3 MPa. Complete inhibition occurred below −2.1MPa. Osmotic potentials in soil compared to matric potentials of the same value were less inhibitory to respiration and acetylene reduction by Azotobacter. The N2-fixing efficiency (mg N/g glucose) was not influenced by water potentials ranging from −0.1 to −2.1 MPa.
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  • 50
    ISSN: 1573-5036
    Keywords: C2H2 reduction ; Intact-plant assay ; Millet ; Nitrogen fixation ; Nitrogenase activity ; Sorghum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A non destructive intact-plant assay for estimating nitrogenase activity (C2H2 reduction) of pot-grown sorghum and millet plants is described. Plants with intact shoots sustained more activity than plants whose tops were removed prior to the assay. With this technique individual plants can be assayed several times during their life cycle. The C2H2 reduction was linear up to 16h incubation in this assay procedure. More rapid diffusion of C2H2 was achieved by injection through a Suba seal in the bottom of the pot. The equlibration of injected C2H2 in the gas phase of the pots filled with sand and sand:FYM media was completed within 1 h. Significantly higher nitrogenase activity and better growth of sorghum and millet plants occurred when plants were grown in a mixture of sand and farmyard manure (FYM) than when plants were grown in vermiculite, soil, or sand + soil medium. Nitrogenase activity and plant growth were greater in a mixture of sand with 2 and 3% FYM than with 0.5 and 1% FYM. Activity was higher when the plants were incubated at 33°C and 40°C than at 27°C. Activity also increased with increasing soil moisture. There were significant differences amongst 15 sorghum cultivars screened for associated nitrogenase activity. This new technique has good prospects for screening cultivars of millet, sorghum and other grain crops for their nitrogen-fixing ability.
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  • 51
    ISSN: 1573-5036
    Keywords: Azospirillum brasilense ; Azotobacter chroococcum ; Effect on yield ; Inoculation ; Nitrogen fixation ; Setaria italica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Under controlled conditions in pots filled with sand, vermiculite and field soil, inoculation withA. brasilense-Cd ATCC 29729 or withAzotobacter chroococcum caused increases above controls in the weight and N content of panicles ofSetaria italica. In no case, however, did N increases in test plants exceed the initial total N content. High acetylene reduction activities (1,000–2,000 nmole/h/pot) could be found only in plants inoculated withAzospirillum. Inoculation withAzospirillum (strain-Cd) in the field caused a significant increase above noninoculated controls of 18.5% in shoot dry weight, ofSetaria italica. Azotobacter caused a non significant increase of 8%. No significant differences were found between yields ofSetaria italica grown in soil inoculated withA. chroococcum, and those of plants grown in the presence ofA. vinelandii. A. brasilense-Cd was more effective in the field thanA. brasilense Sp-7 ATCC 29145. The results suggest that Azospirillum may increase yields ofS. italica more efficiently than Azotobacter under local field conditions.
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  • 52
    ISSN: 1573-5036
    Keywords: Clover ; Nitrogen fixation ; Rhizobium ; Root nodule ; Selection and plant breeding ; Symbiosis ; Trifolium pratense ; T. subterraneum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary This paper reviews (i) basic studies on the genetics of symbiosis in red clover (a self-sterile species) and subterranean clover (cleistogamous) and (ii) work on selection and plant breeding to increase nitrogen fixation in these hosts. Symbiotic effectiveness in red clover is influenced by many major and minor genes. The highly effective phenotype is inherited in a complex manner associated with early nodulation and the formation of large amounts of persistent bacteroid-containing tissue. Lines bred to fix more nitrogen with one strain ofRhizobium trifolii do so with most but not all other strains examined. They also show slightly increased vigour when grown on nitrate. The highly effective response is correlated with abundant nodulation and an early flowering habit, the evidence from breeding studies indicating that this correlation is not absolute. Normally effective and highly effective nodules have the same specific nitrogenase activities. The expression of the highly effective response is relatively little affected by environmental factors (temperature, light intensity, day length, supplementary carbon-di-oxide). Inbreeding substantially degrades the symbiotic response. Heterosis is shown in crosses between cultivars of subterranean clover but otherwise selection to increase effectiveness in this host was unsuccessful. The relevance of these results (and their physiological aspects) for the improvement of grain legumes is discussed.
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  • 53
    ISSN: 1573-5036
    Keywords: Assimilates distribution ; 14CO2 and15N2 labelling ; Glycine max L. Merrill ; Nitrogen fixation ; Respiration costs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Summary Distribution and use of photoassimilated carbon by nodulated soybeans (Glycine max L. Merr.) grown in natural conditions have been studied during two consecutive years by successive and simultaneous exposures of the plants to14CO2 and15N2 during one day. This method, together with detailed analysis of CO2 efflux by root systems made it possible to follow the fate of carbon in relation to dinitrogen fixation. The results showed that the stage of development at which the plants were labelled exerted a high influence on the initial distribution of carbon. The growing organs always attracted more of the recently assimilated carbon. So, the reproductive parts accumulated increasing proportions and by day 100 about 70% of the current net production was recovered in pods and seeds. Nodules stored from 3 to 5% of the daily production, from day 50 to day 100, when their fixation activity already dropped by day 85. During the period of optimal fixation the amount of carbon lost as CO2 due to the only process of N2 reduction ranged between 2.5 and 7 mg per mg of N2 fixed. This was equivalent to the amount of carbon directed towards roots and nodules structures during the same time. Secondary transfers by remobilization occurred from leaves and pods to the grains but mainly from the carbon assimilated during the podfilling stage (after day 80). However, these amounts were small indicating that grain development is mainly supported by current assimilates.
    Notes: Resumé La distribution et l'utilisation du carbone photoassimilé par des sojas (Glycine max L. Merr.) nodulés, cultivés en conditions naturelles ont été suivies durant deux années consécutives par expositions répétées et simultanées de plantes à du14CO2 et15N2 pendant une journée. Cette méthode couplée à une analyse détaillée des flux respiratoires au niveau des systèmes racinaires a permis de suivre le devenir du carbone en relation avec l'activité fixatrice d'azote. Les résultats montrent que le stade de développement des plantes au moment du marquage exerce une forte influence sur la distribution initiale du carbone. Ce sont les organes en forte croissance qui attirent le plus d'assimilats récents. Ainsi les organes reproducteurs, accumulent des quantités croissantes à partir de leur formation si bien qu'aux environs du jour 100, ils attirent près de 70% de la production nette. Les nodules eux stockent da 3 à 5% de cette production journalière entre les jours 50 et 100 alors que leur activité fixatrice chute déjà fortement dès le jour 85. Pendant la phase d'activité fixatrice optimale, les quantités de carbone perdues sous forme de CO2, pour le seul processus de réduction du N2, varient entre 2,5 et 7 mg par mg d'azote fixé. Ceci équivaut à la quantité de carbone destinée aux structures “racines et nodules”. Les transferts secondaires d'organes à organes se font à partir des organes végétatifs et puis des gousses vers les graines, mais essentiellement à partir de carbone assimilé durant la phase de remplissage des gousses (après le jour 80). Cependant, les quantités remobilisées sont faibles, ce qui indique que la croissance des graines dépend surtout d'une alimentation directe à partir de la photosynthèse.
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  • 54
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    Plant and soil 82 (1984), S. 273-284 
    ISSN: 1573-5036
    Keywords: Legume ; Nitrogen fixation ; Rhizobium ; C and N economy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Studies of the C and N economy of a range of temperate and tropical legume/Rhizobium symbioses indicate considerable variation (up to three-fold) in the cost of N2 fixation. Comparisons between and within symbioses indicate that the proportion of net photosynthate utilized in nodule functioning varies almost ten-fold from as low as 3% to as high as 25%. Factors possibly responsible for variation in efficiency of C use in nodules and in the proportioning of translocated photosynthetic products to nodules are discussed.
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  • 55
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    Plant and soil 81 (1984), S. 133-141 
    ISSN: 1573-5036
    Keywords: Benomyl ; Pesticides ; Nitrogen fixation ; Soybeans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Benomyl applied to the seeds of soybean (Glycine max L. Merrill) inoculated with a benomyl resistant strain ofRhizobium japonicum increased the relative abundance of nodules formed by the inoculum strain and the numbers of the added rhizobium on the roots, the total N content, the percentage N, the yield at one plant density and, in one of four soils, the pod weight of soybeans grown in the greenhouse. Oxamyl applied to the seeds, foliage or both of soybeans inoculated with an oxamyl resistant strain ofR. japonicum increased the yield, N content, percentage N, and weight of nodules, pods and grain and enhanced the relative frequency of nodules formed by the inoculum strain. It is suggested that pesticides or other antimicrobial agents and rhizobia resistant to these inhibitors may provide a new means for increasing nitrogen fixation by soybeans.
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  • 56
    ISSN: 1573-5036
    Keywords: Azospirillum lipoferum ; Grain yield ; N-content ; Nitrogen fixation ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Spring wheat (Triticum aestivum var. Arkas) was associated withAzospirillum lipoferum under greenhouse and field conditions of a temperate region. Controls were treated with autoclaved bacteria. The soils used were: sand, sandy loam, and a peat-clay mixture. In experiments run over a period of three years, there were increases in grain yield, N-yield of the grains, and 1000 grain weight. Depending from environmental conditions, increase changed from year to year, and within one given year. There was, however, no experiment without positive response to the inoculation. Highest grain yield increase (70%) was found on sand supplemented with P and K only, but up to 32% were also obtained on peat-clay soil containing 0.28% total N. Under greenhouse conditions, one third of technical N-fertilizer could be saved by bacterial activities. With high probability the effects observed have been at least partly due to bacterial N2-fixation, because the N-yield of the grains was increased (up to 33%), and the most pronounced response was found on sand without any N-fertilizer added.
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  • 57
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    Plant and soil 82 (1984), S. 329-335 
    ISSN: 1573-5036
    Keywords: Legume breeding ; Medicago sativa ; Nitrogen fixation ; Rhizobium ; Trifolium repens ; Vicia faba
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary This paper examines evidence which quantifies the relative importance of legume and Rhizobium genotypes as determinants of phenotypic variation in symbiotic nitrogen fixation. It demonstrates potentially large and unpredictable effects of the Rhizobium genotype. The likely importance of such effects on crop yield is considered. The information is then used to assess ways in which legume breeding programmes may be altered to encompass the effects of genetic variation in Rhizobium.
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  • 58
    ISSN: 1573-5036
    Keywords: Co-evolution ; Domestication ; Gene centre ; Genetic variability ; Nitrogen fixation ; Pisum sativum L ; Rhizobium leguminosarum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Soil samples from several European countries; Sweden, the Netherlands, Spain, Italy and Greece, contained rhizobial populations capable of forming an effective symbiosis with the cultivated pea cv. Rondo from the Netherlands. The range of variation among the European Rhizobium strains, as expressed on pea cv. Rondo, was not so large and almost the same variation could be found within the rhizobial population within each country. Superior Rhizobium strains for the Dutch pea were not restricted to soils from the Netherlands but were also found in those from Sweden and Italy. Soils from Turkey and Israel also contained Rhizobium strains capable of nodulating pea cv. Rondo. However, the genetic variation among these Middle East Rhizobium strains was much larger than that of the European strains. When tested on pea cv. Rondo the majority of the Middle East strains belonged to the medium or low effective classes and only a few strains were comparable with European Rhizobium strains. Dutch Rhizobium strains induced effective nodules on both the Dutch pea cv. Rondo and the Swedish cv. L 110. However, in association with a Turkish Rhizobium strain effective nodules were formed on pea cv. Rondo and ineffective nodules on cv. L 110. We suggest that the genetic uniformity of EuropeanR. leguminosarum strains is the result of selection and domestication of Rhizobium strains originally derived from the gene centres of the pea plant.
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  • 59
    ISSN: 1573-5036
    Keywords: Alfalfa ; Correlation coefficient ; Factor analysis ; Leaf area ratio ; Nitrogen fixation ; Net assimilation rate ; Path-coefficient analysis ; Relative growth rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Twelve alfalfa cultivars inoculated with an indigenous strain (RM9) ofRhizobium meliloti, were compared for their seedling morphological characters, and growth characters, including net assimilation rate (NAR), relative growth rate (RGR), leaf area ratio (LAR) and relative nitrogen assimilation rate (RN). Highly significant differences were obtained between cultivars for most characters. Simple correlation showed that NAR influenced RGR (r=0.91) more than leaf area ratio (LAR) (r=−0.44), and that most characters measured were highly correlated with seedling dry weight. Factor analysis showed that NAR, RGR and RN contributed 25% of the total variation in the dependence structure. The grouping indicated that the higher the NAR and RN the greater was the RGR. Path-coefficient analysis showed that NAR had more important direct and indirect effects than RN in dry matter accumulation. The relationship implied that selection for plants with high NAR, or high efficiency in converting light energy to dry matter production could contribute greater N2 fixation in alfalfa.
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  • 60
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    Plant and soil 59 (1981), S. 473-477 
    ISSN: 1573-5036
    Keywords: Hexachloroxyclohexane ; Nitrogenase activity ; Nitrogen fixation ; Redox potential ; Rhizosphere ; Rice plant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The influence of application of hexachlorocyclohexane (HCH=gamma BHC), to a submerged tropical field soil at rates equivalent to recommended field rates (1–2.5kg a.i./ha) and twice this level, upon the rhizosphere soil nitrogenase, nitrogen fixers, and soil redox potential (Eh) was investigated. The rhizosphere soil from HCH-treated field exhibited significantly higher nitrogenase activity than that from untreated fields. HCH retarded the drop in redox potential of the field soil upto 80 days after transplantation under submerged conditions. Populations of nitrogen-fixingAzospirillum sp. and Azotobacter, to a greater extent, and anaerobic organisms, to a lesser extent, were stimulated in HCH-treated soils. Results indicate the stimulation of heterotrophic nitrogen-fixing bacteria by HCH in submerged paddy soils.
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  • 61
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    Plant and soil 60 (1981), S. 139-142 
    ISSN: 1573-5036
    Keywords: Legumes ; Nitrogen fixation ; Nodulation ; Winged beans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Only legumes of the cowpea cross-inoculation group, including the winged bean (Psophocarpus tetragonolobus) were found to form nodules in a temperate zone soil with no previous history of legume cropping. Isolates from root nodules from uninoculated winged beans grown in the field only nodulated legumes in the cowpea cross-inoculation group.Rhizobium japonicum formed ineffective nodules with the winged bean.
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  • 62
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    Plant and soil 60 (1981), S. 309-315 
    ISSN: 1573-5036
    Keywords: Acetylene reduction ; Aeschynomene americana ; Flooding ; Leaf water potential ; Nitrogen fixation ; Soil moisture deficits
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Studies on the tolerance ofAeschynomene americana L. to periods of flooding or soil moisture deficit were conducted in an attempt to elucidate nitrogen fixation as affected by soil moisture. Nitrogenase activity was not reduced significantly in pot-grown Aeschynomene plants subjected to flooding in greenhouse conditions. After 20 days of withholding water from the soil, nitrogenase activities of the drought-stressed plants were much lower than those of either the well-watered or flooded plants. Leaf water potentials were similar in flooded and control plants; however, the droughted plants had leaf water potentials that were 4 bars lower than those of the control plants. Aeschynomene plants were tolerant to long-term periods of flooding, but exhibited a reduction in nitrogenase activity and leaf water status when subjected to soil moisture deficits.
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  • 63
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    Plant and soil 61 (1981), S. 93-111 
    ISSN: 1573-5036
    Keywords: Ineffective nodules ; Medicago laciniata ; Nitrogen fixation ; Nodulation ; Root temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Medicago laciniata, an annual leguminous plant of Saharo-Sindian origin, is particularly refractory to root nodulation by most strains ofRhizobium meliloti. Using a series of such bacterial strains belonging to the 8 groups of Brockwell and Hely, and a variety of environmental conditions, it was noted that several normally non-nodulating strains (at 20°C) produced ineffective nodules at root temperatures of 24°C to 28°C. Nodulation at 20°C failed to occur in the presence of a wide variety of test compounds and physical conditions. No phytoalexins or anti-Rhizobium growth inhibitors were isolated from inoculated root tissue at any temperature. Temperature shift experiments indicated no infection of the root hairs at 20°C, and infection threads produced at the permissive root temperature failed to elongate after transfer to 20°C. However, if meristematic activity had been initiated in the inner root-cortical cells as a result of infection thread penetration at 28°C, no blockage of nodule maturation occurred upon subsequent transfer to 20°C root temperature. Nodules produced at 28°C were completely devoid of nitrogenase activity, although the apical (but not the distal) regions contained normal-appearing bacteriods, surrounded by enclosing membranes, and possessed a fully functional leghaemoglobin. A shortage of metabolic energy did not appear to be involved in the ineffective response. A hypothesis to explain the nodulation phenomenon observed was based on the observation in the roots of 2 factors present at 20°C but not at 28°C.
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  • 64
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    Plant and soil 61 (1981), S. 135-143 
    ISSN: 1573-5036
    Keywords: Hydrogen ; Nitrogen fixation ; Nodulated roots ; Pea ; Respiration ; Soya bean
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Oxygen uptake, carbon dioxide evolution and nitrogenase activity, measured either as hydrogen evolution (under argon 80%, oxygen 20%) or as the reduction of acetylene to ethylene, were assayed over the same time period by a direct mass-spectrometric method. When carbon dioxide evolution was used to estimate carbohydrate consumption, the results agreed with other work on whole plants. The RQ values obtained in these experiments were always less than 1.0 and thus the carbohydrate consumption calculated from oxygen uptake suggests that previous estimates, using carbon dioxide evolution as a measure of the cost of nitrogen fixation may be underestimates. Lag periods observed in the reduction of acetylene to ethylene suggest that there is a resistance to diffusion of gases in the root nodules.
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  • 65
    ISSN: 1573-5036
    Keywords: Biofuel ; Leguminous trees ; Nitrogen fixation ; Semi-arid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Sand culture pot experiments were carried out with Proposis seedlings in the greenhouse on a nitrogen free nutrient solution with increasing levels of sodium chloride. All species tolerated a 6,000 mg/l salinity with no reduction in growth.P. velutina was the only species that poorly tolerated the 12,000 mg/l salinity level.P. articulata, P. pallida, andP. tamarugo tolerated 18,000 mg/l NaCl with little reduction in growth and grew slightly in a salinity (36,000 mg/l NaCl) greater than seawater. This is the first legume known to grown in salinities equivalent to seawater.
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    Plant and soil 61 (1981), S. 53-63 
    ISSN: 1573-5036
    Keywords: Acetylene reduction ; Inoculation ; Klebsiella oxytoca ; Nitrogen fixation ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Of 45 fermentative gram negative bacterial isolates examined from wheat roots, three were capable of fixing atmospheric nitrogen as determined by the acetylene reduction technique and by protein contents of cells. A gram negative non-motile facultatively anaerobic bacterial strain capable of N2 fixation was identified asKlebsiella oxytoca ZMK-2. Optimal growth and N2 fixation occurred at pH 6.5. The optimum temperatures for growth under anaerobic conditions ranged between 30°–37°C. Acetylene reduction by intact cells was strikingly inhibited by 0.1 atm. or greater partial pressure of O2. Furthermore, the accumulation of H2 in the gas phase over cultures ofKlebsiella oxytoca ZMK-2 at partial pressures greater than 0.02 atm. resulted in a striking inhibition in the rate of C2H2 reduction. The addition of suspensions of eitherKlebsiella oxytoca ZMK-2 orAzotobacter vinelandii or a mixed culture of these two organisms to axenic cultures of wheat plants produced no significant increase in plant growth as measured by plant dry weight or nitrogen content of plants.
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  • 67
    ISSN: 1573-5036
    Keywords: Azospirillum brasilense ; Cereals ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The potential of the nitrogen fixing bacteriumAzospirillum brasilense to enhance development and increase growth of several gramineae was investigated. In both sterilized and non-sterilized systems heading and flowering occurred earlier in the inoculated plants as compared to the noninoculated ones. Total shoot and root weights, total-N content, plant height and leaf length were significantly increased by inoculation.
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  • 68
    ISSN: 1573-5036
    Keywords: Host selection ; Nitrogen fixation ; Nodule structure ; Rhizobium trifolii ; TemperatureTrifolium pratense
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary 1. Nodule structure was examined in the red clover cultivar S123 and in lines (designated H2) separately bred for high yield withRhizobium trifolii strains RCR 0403 and RCR 5. Plants were grown at 16/11, 22/17 and 27/22°C in a 16 h day at 25,000 lux. 2. The larger yields of bred lines compared with S123 were directly correlated with larger aggregate nodule size, larger infected zones and with more bacteroid tissue. Over all treatments the correlation of plant dry weight with aggregate areas of bacteroid tissue, assessed in median longitudinal section, accounted for 79% of the variance. 3. Yields were unrelated to the proportion of uninfected cells and vacuoles within the bacteroid zone. 4. Effects of host type and strain on nodule structure and yield were greatest at the moderate temperature and least and most irregular at high temperature. 5. Bacteriod tissue degenerated more rapidly in S123 than in the bred lines, more rapidly with RCR 0403 than RCR 5 and more rapidly at the high temperature than at moderate or low temperatures. 6. Aggregate nodule size irrespective of treatment was correlated with the aggregate sizes of nodule meristem and differentiating tissues. Nodule comtex comprised a larger proportion of the nodule section at 17 days than subsequently. Other than as specified above, the size relationships of the different tissues of the nodule were unaffected by host selection, temperature, bacterial strain or plant age. 7. At 22/17°C over a 17–25 day period the increment in dry matter per mm2 active nodule tissue was similar for H2 and S123 plants and was less for RCR 0403 (3.33 mg) than for RCR 5 (6.87 mg). At 27/22°C the effeciency of bacteroid tissue was much less,viz. 0.67 and 1.23 mg per mm2 respectively. 8. Nodule tissue areas and volumes were closely related so that unit volumes of active bacteriod tissue in general promoted similar dry matter increment in S123 and bred lines,viz. about 50.5 mg mm−3 at 22/17° for RCR 0403 and 80.8 mg mm−3 for RCR 5. The latter was associated with a fixation rate of 0.157 mg N mm−3 active tissue day−1.
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    Plant and soil 61 (1981), S. 189-202 
    ISSN: 1573-5036
    Keywords: Actinomycete symbiosis ; Alder ; Alnus glutinosa ; Endophyte ; Farmyard manure ; Forestry ; Frankia ; Inoculation ; Nitrogen fixation ; Nodulation ; Root nodules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The occurrence and the infectivity of Frankia, the root-nodule endophyte ofAlnus glutinosa, were studied in different kinds of soil in the Netherlands. Both field and pot experiments indicated that many soils, on which alders have not been grown before, had low numbers of endogenous Frankia or none at all. Inoculation of these soils usually enhanced growth and nodulation of alders. The effect of fertilizer treatments on growth and nodulation ofA. glutinosa were studied in experimental plots. Alders grown in sandy soils, dressed with farmyard manure had the highest yield and the most nodules. The influence of inoculation with homogenates of Sp(+) and Sp(−) nodules and with a pure culture of Frankia AvcIl were studied in pot experiments. The quantity of different kinds of inoculum needed to obtain good growth and nodulation of alder was estimated. The results indicated that addition of a nodule homogenate of 90 g fresh AvcIl Sp(+) nodules is sufficient to inoculate one hectare of nursery soil to produce 10 nodules per plant, while a thousand times larger amount of inoculum is necessary when Sp(−) nodules are used. The limitations and the potentials of using nodule homogenates and pure cultures of Frankia for inoculation in forestry are discussed.
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    Plant and soil 82 (1984), S. 315-327 
    ISSN: 1573-5036
    Keywords: Breeding ; Competition ; Glycine max ; Nitrogen fixation ; Nodulation ; Phaseolus vulgaris
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary While symbiotic nitrogen (N2) fixation byG. max andP. vulgaris reduces their need for combined N, N2 fixation under field conditions is rarely maximized. This paper reviews constraints to N2 fixation in these species, then examines the genetic variability recorded for traits affecting N2 fixation and the further work needed in this area. It considers emerging programs for the improvement of N2 fixation inG. max andP. vulgaris and pays particular attention to methodological considerations.
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    Chromatographia 14 (1981), S. 576-578 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Tortuosity factor
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    Topics: Chemistry and Pharmacology
    Notes: Summary The relationship between the obstructive factor γ and velocity was restudied. The dependence of the obstructive factor on velocity was verified. The effects of diffusion coefficient and particle-to-column diameter ratio on the obstructive factor-velocity relationship were investigated. The results are consistent with Hawkes' hypothesis that values of γ at low velocities are averages over tightly packed and loosely packed domains while at high velocities they are weighted in favour of the loosely packed domains where there is more flow.
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    Chromatographia 14 (1981), S. 648-652 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Gas-liquid adsorption ; Bulk solution ; Mixed stationary phases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary It is shown that the blending of some retention effects can make the resolution of complex mixtures on short classical columns as effective as on capillary columns.
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    Chromatographia 14 (1981), S. 699-703 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Headspace analysis ; Aromatic hydrocarbons ; Water analyses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The possibilities of using headspace analysis of aromatic hydrocarbon traces in aqueous solutions with changing values of the partition coefficients are discussed. A variant of headspace analysis of the simplest aromatic hydrocarbon in natural and waste water is described. It involves two-step gaseous extraction of a sample in vessels of varying volume before and after the equilibrium phase is replaced with a pure gas (air or nitrogen). This method permits to analyse 5–50 ml water samples with benzene and toluene contents varying from the ppb to the ppm range within an error not exceeding 155. The analysis time is about 1.5 h. The presence of non-volatile organic or mineral substances does not influence the determination. This method is unsuitable to heterogeneous systems (aqueous oil emulsions): before carrying out the analysis for the hydrocarbon content these systems have to be homogenized first.
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  • 74
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Open tubular (capillary) columns ; Glass columns ; Fused-silica columns ; Column testing
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    Topics: Chemistry and Pharmacology
    Notes: Summary Column characteristics affecting the chromatographic behavior of glass and siliceous glass (“fused silica”) capillary columns include the dimensional uniformity of the column, the physical and chemical characteristics of the column wall and the characteristics of the liquid phase. In the case of the coated column the uniformity and thickness of the liquid phase film are the most important criteria affecting column reproducibility. The paper discusses these factors and their influence on column performance.
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  • 75
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    Chromatographia 14 (1981), S. 203-211 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Quantitative analysis ; Copper oxide converter ; Inorganic gas analysis ; Determination of fluorine and oxygen ; Hydrocarbon analysis ; Wine analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A review of past activities concerning selected industrial analytical problems is given. This includes the following question: preparation of pure gas mixtures to be used for calibration, catalytic conversion of ester and pyridin samples to carbon dioxide and a one-point calibration method using peak heights, both for quantitative analysis, analysis of gas mixtures containing fluorine and inorganic fluorine compounds and the determination of the oxygen and fluorine content of the sample, separation and identification of hydrocarbons in shale oil and petroleum fraction samples, and analysis of wine.
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  • 76
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    Chromatographia 14 (1981), S. 143-147 
    ISSN: 1612-1112
    Keywords: Capillary columns ; Gas chromatography ; Retention index ; Structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention index of twenty different homologous series of esters have been determined experimentally on polar (Carbowax 1540) and non-polar (squalane) columns. General equations to calculate retention index have been established by statistical methods. The influence of the length and inductive effect of acid and alcohol chains and the relative position of the carboxylic group are discussed.
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  • 77
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    Chromatographia 14 (1981), S. 285-288 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Porous layer open tubular columns ; Kaolin as support ; Column performance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary PLOT columns have been prepared with kaolin as the liquid phase support. These columns show good efficiency with different stationary phases and good thermal stability with polar phases. The performance of columns is shown by the separation of various mixtures such as fatty acids, phenols and anilines which are of analytical importance.
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  • 78
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    Chromatographia 14 (1981), S. 39-40 
    ISSN: 1612-1112
    Keywords: Xylidine isomers ; Heteroaromatic liquid phases ; Gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Nicotinic acid and 1H-benzotriazole appreciably resolved all the xylidine (dimethylaniline) isomers, while benzimidazole, nicotinamide and phthalimide can also separate all the isomers except 2,4- and 2,3-xylidines. The analyses were carried out on supports which were not treated with an alkali.
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  • 79
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    Chromatographia 14 (1981), S. 345-350 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Silica capillaries ; Glass capillaries ; Mixed gum phases ; Polarity and selectivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Mixed phases of Superox 20M and OV-1 can be coated homogeneously on the untreated wall of fused silica capillary columns. Excellent columns with regard to efficiency, inertness and thermal stability can be obtained. (CE〉95% and MAOT≥250°). The polarity and selectivity were ascertained with Rohrschneider-Reynolds probes and a capillary polarity test mixture. The analysis of an essential oil mixture illustrates the possibilities of mixed phases in practical capillary GC.
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  • 80
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Capillary columns ; Fused silica ; Contact angle ; Wettability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary This paper describes the systematic characterization of glass and the newly introduced fused silica and quartz capillary columns from surface wettability measurements. Common gas chromatographic stationary phases were used in capillary-rise measurements at temperatures up to 300°C. By construction of Zisman plots and using the Cassie equation, the relative surface concentrations of wettable and non-wettable groups were determined. By application of the Fowkes equation, the dispersion force component of the surface energy was investigated. The influence of various surface treatments such as leaching, silylation, and polymeric film formation are discussed. Wettability measurements were also used to evaluate the thermostability of various treated surfaces and to compare the surface properties of glass, quartz, and fused silica. The wettability of the surfaces with selected stationary phases as a function of temperature is also discussed.
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  • 81
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Polycyclic aromatic hydrocarbons ; Retention index ; Average molecular polarizabilities
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    Topics: Chemistry and Pharmacology
    Notes: Summary A significant correlation has been found between the retention indices of polycyclic aromatic hydrocarbons on non-polar stationary phases and the average molecular polarizabilities of the molecules separated on these phases. Equations have been derived for the determination of the average molecular polarizabilities, directly from the retention indices.
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  • 82
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    Chromatographia 14 (1981), S. 69-72 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Polynuclear aromatic hydrocarbons ; Retention index ; Vapour pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention index of a planar polynuclear aromatic hydrocarbon on the GC phases OV-101, SE-52, and OV-17 is strictly related only to the boiling point, and less closely to the relative molecular mass. The very approximates relation with connectivity index ins only a consequence of the latter. On a nematic lqiuid crystal phase, a variation of activity coefficient, expressed in terms of a shape factor, also influences the retention of PAH.
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  • 83
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    Chromatographia 14 (1981), S. 269-276 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Detector performance ; Trace analysis ; Catalytic conversion ; Multidimensional gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Relationships are derived describing how the detection limit of a chromatographic system depends on the minimum detectable limit of the detector and the chromatographic parameters such as column length, efficiency, carrier gas flow rate and the capacity factor. Performance data of detectors developed in the last 25 years at the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences are given and a few selected application examples are listed. These include trace analysis by preconcentration and by direct analysis and the utilization of multidimensional gas chromatography with two columns, two detectors, a 12-port valve, and a catalytic conversion reactor.
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  • 84
    ISSN: 1612-1112
    Keywords: Gas chromatography ; C1−C5 Hydrocarbons ; Dimethyl ether
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An analytical GC method was developed which uses a single packed column consisting of three packings in series prepared with the following liquid phases: dimethyl sulfolane, propylene carbonate, and silver nitrate. This system provides satisfactory resolution of mixtures of C1−C5 hydrocarbons and dimethyl ether obtained when converting methanol to gasoline. Due to the high capacity of the column it is possible to inject larger sample amounts permitting trace analysis.
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  • 85
    ISSN: 1612-1112
    Keywords: Phthalides ; Umbelliferae ; Liquid-solid chromatography ; Gas chromatography ; Ligustilide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A liquid-solid chromatographic pre-fractionation of naturally occurring phthalides has been developed. The LSC was carried out on a column of silica applying a 1–50% gradient elution of diethyl ether (containing 2% methanol) in pentane. The enrichment in the fractions led to better possibilities for a gas chromatographic separation and isolation allowing further studies by spectroscopic methods. Ligustilide may easily isomerize during GC as a result of ageing of the column.
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  • 86
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    Chromatographia 18 (1984), S. 367-368 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Open tubular (capillary) columns ; Variation of film thickness ; Thick-film columns ; Mass transfer terms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The factors characterizing the influence of the variation of the liquid phase film thickness on the mass transfer terms in the Golay equations describing the performance of open tubular columns are investigated and numerical values are given.
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  • 87
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    Chromatographia 14 (1981), S. 601-602 
    ISSN: 1612-1112
    Keywords: Ethanolamines ; Ethylene glycols ; Direct separation ; Gas chromatography ; Short glass capillaries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An effective and rapid GC separation of ethanolamines, even in the presence of ethylene glycols, using short glass capillary columns is developed. No preliminary derivatisation of the sample is necessary. The separation is completed in 6 minutes.
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  • 88
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    Chromatographia 14 (1981), S. 507-509 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Headspace ; Phenol ; Urine ; Enzymatic hydrolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new method has been developed for the determination of phenol in urine in which the phenol conjugates are hydrolysed enzymatically and the liberated phenol is analysed by headspace chromatography. The results compare favourably with those obtained by the method of van Haaften and Sie in which acid hydrolysis is carried out in a heated GC precolumn. The enzymatic hydrolysis headspace technique appears to be very reliable and does not suffer from the disadvantages of precolumn acid hydrolysis.
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  • 89
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    Chromatographia 14 (1981), S. 421-424 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Liquid sulfur ; McReynolds' constants
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    Topics: Chemistry and Pharmacology
    Notes: Summary The McReynolds' constants for liquid sulfur as a stationary phase in gas-liquid chromatography (GLC) are presented. A simple graphical method of pattern analysis is used to indicate the uniqueness of the sulfur column as compared with other stationary liquid phases characterized by McReynolds. The limitations of using a single factor (as polarity) for the basis for the selection of GLC columns is discussed.
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  • 90
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Kováts retention indices ; Propellants ; Solvents ; Aerosol packs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary A gas chromatographic method is described by which a nearly complete separation of all commonly used propellants and solvents and their identification and determination can be achieved in one step. The separation is by simple adsorption chromatography on columns packed with Porapak-T with a temperature program 100–180°C at 10°C/min. Kováts' retention indices have been calculated for isothermal conditions at 150°C respectively 100°C for the propellants, at 180°C for the solvents. An exact identification of the propellants and solvents by means of the Kováts' indices is practicable even in complex mixtures.
    Notes: Zusammenfassung Es wird eine gas-chromatographische Methode angegeben, welche eine fast vollständige Auftrennung aller handelsüblichen Aerosol-Treibgase und Lösungsmittel und ihre Identifizierung und Bestimmung in einem Schritt gestatet. Die Trennung erfolgt durch reine Adsorptions-Chromatographie and Porapak T-Säulen bei 100–180°C mit einer Temperaturate von 10°C/min. Zur Bestimmung der Retentionsindices nach Kovats wurden die Treibgase isotherm bei 150°C bzw. 100°C, die Lösungsmittel bei 180°C aufgetrennt. Anhand der Kovats-Indices ist eine eindeutige Identifizierung der Treibgase und Lösungsmittel selbst in vielfältigen Gemischen möglich.
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  • 91
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Cross-linked Stationary phase ; Immobilized Stationary phase ; Packed columns ; Trapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A coating of silicone SE-54 on Chromosorb W has been converted to an analytically stable, immobilized stationary phase layer by cross-linking with an organic peroxide. Up to 10% by weight has been applied in this manner. Excellent high temperature qualities are exhibited, such as low bleeding and good base line stability, during typical analyses. Poly (2,6-dimethyl-p-phenylene oxide) has also been crosslinked as a surface coating on Chromosorb W with an organic peroxide. From 3 to 4% by weight has been immobilized in this way. The resultant packing material, following high temperature conditioning, has been examined for use as an adsorbent of trace substances, similar to the applications to which such adsorbents as Tenax GC have commonly been applied, e.g. trace analysis of air. It appears to exhibit satisfactory properties for this analytical purpose.
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  • 92
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    Chromatographia 18 (1984), S. 21-22 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Isopropylidene-glucose ; Glucose ; GC of TMS-derivatives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary This paper describes the gas chromatographic separation of the mixture of di- and mono-O-isopropylidene-D-glucose and D-glucose as their trimethylsilyl derivatives. The use of OV-101 as liquid phase provides a complete separation for the all components in the mixture. Quantative analysis was performed using xylitol as the internal standard for di- and mono-O-isopropylidene-D-glucose, and sorbitol as the internal standard for α-and β-glucose.
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  • 93
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Nuclear magnetic resonance ; Terpenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A procedure is described for recording1H NMR spectra of flowing gaseous GC fractions boiling as high as 200°C. The line width of the signals in the NMR spectra is smaller than 2.2Hz.
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  • 94
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    Chromatographia 18 (1984), S. 556-559 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Liquid chromatography ; Tetramethrin ; Residues
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method is described for the analysis of tetramethrin aqueous formulation and residues of tetramethrin on woolen cloth. The samples were extracted with acetonitrile and partitioned with benzene. Interferences were removed by liquid column chromatography with acid alumina and eluted with 10% ethyl acetate-hexane. Analysis was by gas chromatography with a 10% UCW98 (methylsilicone) column. Detection was made with the flame ionization detector to avoid the repeated dilutions necessary with use of the electron capture detector.
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  • 95
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Retention index ; Electric parameters ; Physico-chemical relationships ; Structure-retention study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new equation is derived relating the retention index to the molecular polarizabilities, ionization potentials and permanent dipole moments of the stationary phase and the solute. Various implications of this equation to quantitative structure-retention relationships are discussed.
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  • 96
    ISSN: 1612-1112
    Keywords: Aldehydes and ketones ; 2,4-dinitrophenylhydrazine-coated silica gel ; Gas chromatography ; Column liquid chromatography ; Pollution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary After a brief review of several methods described in the literature this paper discusses air-sampling on 2,4-dinitrophenylhydrazine-coated silica gel and identification requirements for aldehydes and ketones most commonly found in industrial pollution. Quantitative analysis of formaldehyde and acetaldehyde either by GC or by HPLC techniques is established using a dynamic system producing test atmospheres and compared with the usual colorimetric determinations.
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