NITROGEN FIXATION BY EXCISED SOY BEAN ROOT NODULES

Fixation of isotopic nitrogen by excised nodules.

After 60 years of research in symbiotic nitrogen fixation, the agent of fixation has not been established. Apparently only two biological species, leguminous plants and Rhisobium, are essential (l), but attempts to separate the components have been unsuccessful. Unequivocal fixation by the intact nodule excised from a plant actively fixing nitrogen has not been demonstrated. Ordinarily, cells o...

Exploring Symbiotic Nitrogen Fixation and Assimilation in Pea Root Nodules by in Vivo

Nitrogen (N) fixation and assimilation in pea (Pisum sativum) root nodules were studied by in vivo N nuclear magnetic resonance (NMR) by exposing detached nodules to N2 via a perfusion medium, while recording a time course of spectra. In vivo P NMR spectroscopy was used to monitor the physiological state of the metabolically active nodules. The nodules were extracted after the NMR studies and a...

The Effect of Potassium on the Fixation of Molecular Nitrogen by Root Nodules of Vicia faba.

The effect of potassium supply of Vicia faba on the fixation of molecular nitrogen by root nodules was studied by using (15)N-labeled molecular nitrogen. Plants well supplied with potassium showed higher contents of (15)N in the soluble amino fraction and in the protein fraction of various plant organs as compared with plants of a lower potassium status. This effect was evident particularly in ...

Carbon Partitioning in Nitrogen-fixing Root Nodules

The sulfate transporter SST1 is crucial for symbiotic nitrogen fixation in Lotus japonicus root nodules.

Symbiotic nitrogen fixation (SNF) by intracellular rhizobia within legume root nodules requires the exchange of nutrients between host plant cells and their resident bacteria. Little is known at the molecular level about plant transporters that mediate such exchanges. Several mutants of the model legume Lotus japonicus have been identified that develop nodules with metabolic defects that cannot...