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. 1986 May;81(1):280–284. doi: 10.1104/pp.81.1.280

Carbohydrate Partitioning and the Capacity of Apparent Nitrogen Fixation of Soybean Plants Grown Outdoors

Eddie P Millhollon 1, Larry E Williams 1,1
PMCID: PMC1075319  PMID: 16664789

Abstract

Patterns of leaf carbohydrate partitioning and nodule activity in soybean plants grown under natural conditions and the irradiance level required to produce sufficient carbohydrate to obtain maximum rates of apparent N2-fixation (acetylene reduction) were measured. Soybean plants, grown outdoors, maintained constant levels of leaf soluble sugars while leaf starch pools varied diurnally. When root temperature was kept at 25°C and shoot temperature was allowed to vary with ambient temperature, the plants maintained constant rates of apparent N2-fixation and root+nodule respiration. Results from a second experiment, in which the entire plant was kept at 25°C, were similar to those of the first experiment. Shoot carbon exchange rate of plants from the second experiment was light saturated at photosynthetic photon flux densities between 400 and 600 micromoles per square meter per second. When plants were subjected to an extended 40-hour dark period to deplete carbohydrate reserves, apparent N2-fixation was unaffected during the first 10 hours of darkness, decreased rapidly between 10 and 16 hours, and plateaued at one-third the initial level thereafter. After the extended dark period, plants were exposed to photosynthetic photon flux density from 200 to 1000 micromoles per square meter per second for 10 hours. Photosynthetic photon flux densities of 200 micromoles per square meter per second and greater resulted in maximum leaf soluble sugar content and nodule activity. Leaf starch content increased with irradiance levels up to 600 micromoles per square meter per second with no further increase at higher irradiance levels. Results presented here indicate that maximum nodule activity occurs at irradiance levels that do not saturate the plant's photosynthetic apparatus. This response would allow for maximum N2-fixation to occur in a nodulated legume during periods of inclement weather.

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Selected References

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

  1. Chatterton N. J., Silvius J. E. Photosynthate Partitioning into Starch in Soybean Leaves: I. Effects of Photoperiod versus Photosynthetic Period Duration. Plant Physiol. 1979 Nov;64(5):749–753. doi: 10.1104/pp.64.5.749. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Chatterton N. J., Silvius J. E. Photosynthate Partitioning into Starch in Soybean Leaves: II. IRRADIANCE LEVEL AND DAILY PHOTOSYNTHETIC PERIOD DURATION EFFECTS. Plant Physiol. 1981 Feb;67(2):257–260. doi: 10.1104/pp.67.2.257. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Finn G. A., Brun W. A. Effect of Atmospheric CO(2) Enrichment on Growth, Nonstructural Carbohydrate Content, and Root Nodule Activity in Soybean. Plant Physiol. 1982 Feb;69(2):327–331. doi: 10.1104/pp.69.2.327. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. 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]
  5. Huck M. G., Hageman R. H., Hanson J. B. Diurnal Variation in Root Respiration. Plant Physiol. 1962 May;37(3):371–375. doi: 10.1104/pp.37.3.371. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Kerr P. S., Huber S. C., Israel D. W. Effect of N-source on soybean leaf sucrose phosphate synthase, starch formation, and whole plant growth. Plant Physiol. 1984 Jun;75(2):483–488. doi: 10.1104/pp.75.2.483. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Mederski H. J., Streeter J. G. Continuous, automated acetylene reduction assays using intact plants. Plant Physiol. 1977 Jun;59(6):1076–1081. doi: 10.1104/pp.59.6.1076. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Schweitzer L. E., Harper J. E. Effect of light, dark, and temperature on root nodule activity (acetylene reduction) of soybeans. Plant Physiol. 1980 Jan;65(1):51–56. doi: 10.1104/pp.65.1.51. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Sheehy J. E., Fishbeck K. A., Dejong T. M., Williams L. E., Phillips D. A. Carbon exchange rates of shoots required to utilize available acetylene reduction capacity in soybean and alfalfa root nodules. Plant Physiol. 1980 Jul;66(1):101–104. doi: 10.1104/pp.66.1.101. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Swanson C. A., Böhning R. H. THE EFFECT OF PETIOLE TEMPERATURE ON THE TRANSLOCATION OF CARBOHYDRATES FROM BEAN LEAVES. Plant Physiol. 1951 Jul;26(3):557–564. doi: 10.1104/pp.26.3.557. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Upmeyer D. J., Koller H. R. Diurnal trends in net photosynthetic rate and carbohydrate levels of soybean leaves. Plant Physiol. 1973 May;51(5):871–874. doi: 10.1104/pp.51.5.871. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Williams L. E., Dejong T. M., Phillips D. A. Carbon and nitrogen limitations on soybean seedling development. Plant Physiol. 1981 Nov;68(5):1206–1209. doi: 10.1104/pp.68.5.1206. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Williams L. E., Dejong T. M., Phillips D. A. Effect of changes in shoot carbon-exchange rate on soybean root nodule activity. Plant Physiol. 1982 Feb;69(2):432–436. doi: 10.1104/pp.69.2.432. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Williams L. E., Phillips D. A. Effect of irradiance on development of apparent nitrogen fixation and photosynthesis in soybean. Plant Physiol. 1980 Nov;66(5):968–972. doi: 10.1104/pp.66.5.968. [DOI] [PMC free article] [PubMed] [Google Scholar]

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