Skip to main content
PMC home page
Plant Physiology logoLink to Plant Physiology
. 1986 Aug;81(4):972–975. doi: 10.1104/pp.81.4.972

Root Respiration Associated with Nitrate Assimilation by Cowpea 1

Hideo Sasakawa 1,2, Thomas A Larue 1
PMCID: PMC1075469  PMID: 16664967

Abstract

Nitrate uptake by roots of cowpea (Vigna unguiculata) was measured using 15NO3−, and the energy cost to the root was estimated by respirometry. Roots of 8-day-old cowpea seedlings respired 0.6 to 0.8 milligram CO2 per plant per hour for growth and maintenance. Adding 10 millimolar NO3− to the root medium increased respiration by 20 to 30% during the following 6 hours. This increase was not observed if the shoots were in the dark. Removal of NO3− from the root medium slowed the increase of root respiration. The ratios of additional respiration to the total nitrogen uptake and reduced nitrogen content in roots were 0.4 gram C per gram N and 2.3 grams C per gram N, respectively. The latter value is close to theoretical estimates of nitrate assimilation, and is similar to estimates of 1 to 4 grams C per gram N for the respiratory cost of symbiotic N2 fixation.

Full text

PDF
972

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Atkins C. A., Pate J. S., Griffiths G. J., White S. T. Economy of Carbon and Nitrogen in Nodulated and Nonnodulated (NO(3)-grown) Cowpea [Vigna unguiculata (L.) Walp.]. Plant Physiol. 1980 Nov;66(5):978–983. doi: 10.1104/pp.66.5.978. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Atkins C. A., Pate J. S., Layzell D. B. Assimilation and Transport of Nitrogen in Nonnodulated (NO(3)-grown) Lupinus albus L. Plant Physiol. 1979 Dec;64(6):1078–1082. doi: 10.1104/pp.64.6.1078. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Crafts-Brandner S. J., Harper J. E. Nitrate Reduction by Roots of Soybean (Glycine max [L.] Merr.) Seedlings. Plant Physiol. 1982 Jun;69(6):1298–1303. doi: 10.1104/pp.69.6.1298. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Mahon J. D. Respiration and the energy requirement for nitrogen fixation in nodulated pea roots. Plant Physiol. 1977 Dec;60(6):817–821. doi: 10.1104/pp.60.6.817. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Neyra C. A., Hageman R. H. Nitrate uptake and induction of nitrate reductase in excised corn roots. Plant Physiol. 1975 Nov;56(5):692–695. doi: 10.1104/pp.56.5.692. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Pate J. S., Layzell D. B., Atkins C. A. Economy of Carbon and Nitrogen in a Nodulated and Nonnodulated (NO(3)-grown) Legume. Plant Physiol. 1979 Dec;64(6):1083–1088. doi: 10.1104/pp.64.6.1083. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Patterson T. G., Larue T. A. Root respiration associated with nitrogenase activity (c(2)h(2)) of soybean, and a comparison of estimates. Plant Physiol. 1983 Jul;72(3):701–705. doi: 10.1104/pp.72.3.701. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Rufty T. W., Volk R. J., McClure P. R., Israel D. W., Raper C. D. Relative Content of NO(3) and Reduced N in Xylem Exudate as an Indicator of Root Reduction of Concurrently Absorbed NO(3). Plant Physiol. 1982 Jan;69(1):166–170. doi: 10.1104/pp.69.1.166. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Sasakawa H., Yamamoto Y. Comparison of the uptake of nitrate and ammonium by rice seedlings: influences of light, temperature, oxygen concentration, exogenous sucrose, and metabolic inhibitors. Plant Physiol. 1978 Oct;62(4):665–669. doi: 10.1104/pp.62.4.665. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Plant Physiology are provided here courtesy of Oxford University Press

RESOURCES