Molybd�n als Katalysator bei der biologischen Stickstoffbindung

Bortels, H.

doi:10.1007/bf00510471

Cited by 229 publications

(63 citation statements)

References 2 publications

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“…of molybdenum was required to supply the needs of young tomato plants. The role molybdenum plays in the fixation of nitrogen by Azotobacter chroococcum had been reported earlier by BORTELS (4).…”

Section: Introductionsupporting

confidence: 53%

Accumulation and Distribution of Molybdenum in the Cotton Plant

Joham

1953

Plant Physiol.

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Section: Introductionsupporting

confidence: 53%

Accumulation and Distribution of Molybdenum in the Cotton Plant

Joham

1953

Plant Physiol.

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“…Phosphorous and sulfur are typical components of lacustrine organic matter (Wetzel, 2001). Molybdenum as a catalyst for nitrogen fixation in living plants is generally accumulated in plant material (Bortels, 1930), but can also be fixed to the organic matter by early diagenetic processes (Robinson et al, 1993). But due to the high accordance of group III to clay, an incorporation of the heavy metals into crystal lattices of clay minerals (Lin and Puls, 2000;Tessier, 1992) has to be considered.…”

Section: Indicators Of Post-depositional Processesmentioning

confidence: 99%

Modern sedimentation patterns in Lake El'gygytgyn, NE Russia, derived from surface sediment and inlet streams samples

et al. 2013

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Abstract. Lake El'gygytgyn/NE Russia holds a continuous 3.58 Ma sediment record, which is regarded as the most longlasting climate archive of the terrestrial Arctic. Based on multi-proxy geochemical, mineralogical, and granulometric analyses of surface sediment, inlet stream and bedrock samples, supplemented by statistical methods, major processes influencing the modern sedimentation in the lake were investigated. Grain-size parameters and chemical elements linked to the input of feldspars from acidic bedrock indicate a windinduced two-cell current system as major driver of sediment transport and accumulation processes in Lake El'gygytgyn. The distribution of mafic rock related elements in the sediment on the lake floor can be traced back to the input of weathering products of basaltic rocks in the catchment. Obvious similarities in the spatial variability of manganese and heavy metals indicate sorption or co-precipitation of these elements with Fe and Mn hydroxides and oxides. But the similar distribution of organic matter and clay contents might also point to a fixation to organic components and clay minerals. An enrichment of mercury in the inlet streams might be indicative of neotectonic activity around the lake. The results of this study add to the fundamental knowledge of the modern lake processes of Lake El'gygytgyn and its lakecatchment interactions, and thus, yield crucial insights for the interpretation of paleo-data from this unique archive.

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“…The dependence on molybdenum for nitrogen fixation was first demonstrated by,Bortels (5), who showed that Mo was required for growth of Azotobacter vinelandii on dinitrogen but not for growth on ammonium. Many years later the biochemical basis for this dependency on Mo was demonstrated by Bulen and LeComte (6), who showed that purified nitrogenase contained Mo.…”

mentioning

confidence: 99%

Variability in molybdenum uptake activity in Bradyrhizobium japonicum strains

Graham¹,

Maier²

1987

J Bacteriol

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Twenty naturally occurring strains of Bradyrhizobium japonicum in 11 serogroups were screened for the ability to take up Mo as bacteroids from soybean root nodules. The strains varied greatly in their ability to take up Mo in a 1-min period. The best strain was USDA 136, which had an Mo uptake activity of almost 3.0 pmol/min per mg of bacteroid (dry weight). In contrast, the poorest strain, USDA 62, had an Mo uptake activity of 0. The dependence on molybdenum for nitrogen fixation was first demonstrated by,Bortels (5), who showed that Mo was required for growth of Azotobacter vinelandii on dinitrogen but not for growth on ammonium. Many years later the biochemical basis for this dependency on Mo was demonstrated by Bulen and LeComte (6), who showed that purified nitrogenase contained Mo. This is apparently true for the nitrogenase from all sources of the varied bacteria able to fix N2. However, there is evidence that A. vinelandii contains another nitrogenase whose activity is independent of Mo (4).The two atoms of Mo contained by component I of nitrogenase are associated with the active site of the enzyme (33).It has been demonstrated that molybdenum is a required trace element for symbiotic N2 fixation as well. Anderson (1,2) found that the addition of Mo to N2-fixing clover resulted in significant increases in plant dry weight. Since then there have been many reports of increased legume dry weight (8-10, 17, 24, 26, 29, 30) and increased symbiotic nitrogen fixation activity (8,9,20,24)

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Molybd�n als Katalysator bei der biologischen Stickstoffbindung

Cited by 229 publications

References 2 publications

Accumulation and Distribution of Molybdenum in the Cotton Plant

Accumulation and Distribution of Molybdenum in the Cotton Plant

Modern sedimentation patterns in Lake El'gygytgyn, NE Russia, derived from surface sediment and inlet streams samples

Variability in molybdenum uptake activity in Bradyrhizobium japonicum strains

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