Abstract
Soybean Glycine max. L. Merr. nodule senescence was studied using the loss of acetylene reduction by intact tap root nodules as its indication. Tap root nodules from two varieties (Calland and Beeson) of field-grown soybeans were used. The specific activities of nitrogenase (micromoles/minute gram fresh weight of nodules) as measured by the acetylene reduction assay decreased abruptly between 58 to 65 and 68 to 75 days after planting the Beeson and Calland soybeans, respectively. Major changes were not detected in dry weight, total nitrogen, and leghemoglobin levels during the period when in vivo nitrogenase activity declined. Ammonium levels in the cytosol of nodules and poly-β-hydroxybutyrate increased moderately just prior to or coincidental with the loss of nitrogenase activity. Neither enzymes that have been postulated to be involved in ammonium assimilation nor NADP+-specific isocitrate dehydrogenase exhibited any large changes in specific activities during the initial period when nitrogenase activity declined.
Full text
PDF




Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- APRISON M. H., MAGEE W. E., BURRIS R. H. Nitrogen fixation by excised soy bean root nodules. J Biol Chem. 1954 May;208(1):29–39. [PubMed] [Google Scholar]
- Appleby C. A. The separation and properties of low-spin (haemochrome) and native, high-spin forms of leghaemoglobin from soybean nodule extracts. Biochim Biophys Acta. 1969 Oct 21;189(2):267–279. doi: 10.1016/0005-2728(69)90053-x. [DOI] [PubMed] [Google Scholar]
- Appleby C. A., Wittenberg B. A., Wittenberg J. B. Nicotinic Acid as a ligand affecting leghemoglobin structure and oxygen reactivity. Proc Natl Acad Sci U S A. 1973 Feb;70(2):564–568. doi: 10.1073/pnas.70.2.564. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Barrera C. R., Jurtshuk P. Characterization of the highly active isocitrate (NADP+) dehydrogenase of Azotobacter vinelandii. Biochim Biophys Acta. 1970 Dec 16;220(3):416–429. doi: 10.1016/0005-2744(70)90273-1. [DOI] [PubMed] [Google Scholar]
- Bergersen F. J., Turner G. L., Appleby C. A. Studies of the physiological role of leghaemoglobin in soybean root nodules. Biochim Biophys Acta. 1973 Jan 18;292(1):271–282. doi: 10.1016/0005-2728(73)90271-5. [DOI] [PubMed] [Google Scholar]
- Bergersen J. F., Turner G. L. Nitrogen fixation by the bacteroid fraction of breis of soybean root nodules. Biochim Biophys Acta. 1967 Aug 29;141(3):507–515. doi: 10.1016/0304-4165(67)90179-1. [DOI] [PubMed] [Google Scholar]
- Dawes E. A., Senior P. J. The role and regulation of energy reserve polymers in micro-organisms. Adv Microb Physiol. 1973;10:135–266. doi: 10.1016/s0065-2911(08)60088-0. [DOI] [PubMed] [Google Scholar]
- Dunn S. D., Klucas R. V. Studies on possible routes of ammonium assimilation in soybean root nodule bacteroids. Can J Microbiol. 1973 Dec;19(12):1493–1499. doi: 10.1139/m73-243. [DOI] [PubMed] [Google Scholar]
- HAYWARD A. C., FORSYTH W. G., ROBERTS J. B. Synthesis and breakdown of poly-beta-hydroxybutyric acid by bacteria. J Gen Microbiol. 1959 Jun;20(3):510–518. doi: 10.1099/00221287-20-3-510. [DOI] [PubMed] [Google Scholar]
- Hardy R. W., Holsten R. D., Jackson E. K., Burns R. C. The acetylene-ethylene assay for n(2) fixation: laboratory and field evaluation. Plant Physiol. 1968 Aug;43(8):1185–1207. doi: 10.1104/pp.43.8.1185. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Klucas R. Nitrogen fixation by Klebsiella grown in the presence of oxygen. Can J Microbiol. 1972 Dec;18(12):1845–1850. doi: 10.1139/m72-288. [DOI] [PubMed] [Google Scholar]
- Koch B., Evans H. J., Russell S. Reduction of acetylene and nitrogen gas by breis and cell-free extracts of soybean root nodules. Plant Physiol. 1967 Mar;42(3):466–468. doi: 10.1104/pp.42.3.466. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wong P. P., Evans H. J. Poly-beta-hydroxybutyrate Utilization by Soybean (Glycine max Merr.) Nodules and Assessment of Its Role in Maintenance of Nitrogenase Activity. Plant Physiol. 1971 Jun;47(6):750–755. doi: 10.1104/pp.47.6.750. [DOI] [PMC free article] [PubMed] [Google Scholar]
