|Biochemisch-oekologische Studien zum Phosphathaushalt von Azotobacter chroococcum|Overbeck, J. (1967). Biochemisch-oekologische Studien zum Phosphathaushalt von Azotobacter chroococcum. Helgol. Wiss. Meeresunters. 15(1-4): 202-209. dx.doi.org/10.1007/BF01618624
In: Helgoländer Wissenschaftliche Meeresuntersuchungen. Biologische Anstalt Helgoland: Hamburg. ISSN 0017-9957, more
|Also published as |
- Overbeck, J. (1967). Biochemisch-oekologische Studien zum Phosphathaushalt von Azotobacter chroococcum, in: Kinne, O. et al. (Ed.) Vorträge und Diskussionen. Erstes Europäisches Symposion über Meeresbiologie = Papers and discussions. First European Symposium on Marine Biology = Rapports et discussions. Premier symposium européen sur biologie marine. Helgoländer Wissenschaftliche Meeresuntersuchungen, 15(1-4): pp. 202-209. dx.doi.org/10.1007/BF01618624, more
The influence of different phosphate-compounds, especially of NaH2PO4×2 H2O and fructose-1,6-diphosphate, on nitrogen fixation was studied in three tribes ofAzotobacter chroococcum. In stagnant nonaerated cultures a phosphate-optimum exists for the nitrogenfixation of 90 µg P/ml. Using fructose-1,6-diphosphate the same quantity of nitrogen is fixed with only 50 µg P/ml. In aerated cultures the differences between inorganic phosphate and fructose-1,6-diphosphate (regarding their influence on the nitrogen-fixation) disappear. The quotient: used up C/fixed N also depends on aeration. In stagnant cultures containing organic phosphate-compounds, the C/N-quotient is lower than in those containing inorganic phosphate. In aerated cultures, however, the C/N-quotient is lowest with orthophosphate. The experiments indicate that the phosphate-esters are incorporated into the cell immediately without splitting up on the cell surface. These incorporated phosphateesters in non-aerated cultures, lacking an extensive oxidative phosphorylation, are apparently important for the economy of nitrogen fixation. The ecological role of the incorporation of phosphate-esters is discussed in relation to the fact that a great part of phosphorus in the natural environment is not inorganic but organic phosphate.