Skip to main content
SpringerLink
Log in

Increased root exudation of14C-compounds by sorghum seedlings inoculated with nitrogen-fixing bacteria

  • Published:
Plant and Soil Aims and scope Submit manuscript

Summary

Organic components leaked fromSorghum bicolor seedlings (‘root exudates’) were examined by recovering14C labelled compounds from root solutions of seedlings inoculated withAzospirillum brasilense, Azotobacter vinelandii orKlebsiella pneumoniae nif-. Up to 3.5% of the total14C recovered from shoots, roots, and nutrient solutions was found in the root solutions. Inoculation with Azospirillum and Azotobacter increased the amounts of14C and decreased the amounts of carbohydrates in the root solutions. When sucrose was added as a carbon source for the bacteria, the increase of14C in the solutions did not occur. Quantities of14C found in the root solutions were proportional to amounts of mineral nitrogen supplied to the plants. Bacterial growth also was proportional to nitrogen levels. When sorghum plants were grown in soil and labelled with14CO2, about 15% of the total14C recovered within 48 hours exposure was found in soil leachates.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

Literature Cited

  1. Barber D A and Gunn K B 1974 The effect of mechanical forces on the exudation of organic substances by the roots of cereal plants grown under sterile conditions. New Phytol. 73,39–45.

    CAS  Google Scholar 

  2. Barber D A and Martin J K 1976 The release of organic substances by cereal roots into soil. New Phytol. 76, 69–80.

    CAS  Google Scholar 

  3. Brown M E 1972 Plant growth substances produced by microorganisms of soil and rhizosphere. J. Appl. Bacteriol. 35, 443–451.

    CAS  Google Scholar 

  4. Burk D, Lineweaver H and Horner C K 1934 The specific influence of acidity on the mechanism of nitrogen fixation by Azotobacter. J. Bacteriol. 27, 325.

    CAS  PubMed  Google Scholar 

  5. Burr T J, Schroth M N and Suslow T 1978 Increased potato yields by treatment of seed pieces with specific strains ofPseudomonas fluorescens andP. putida. Phytopathology 68, 1377–1383.

    Google Scholar 

  6. Day J M, Neves M C P and Dobereiner J 1975 Nitrogenase activity on the roots of tropical forage grasses. Soil Biol. Biochem. 7, 107–112.

    Article  CAS  Google Scholar 

  7. Dayan E, Banin A and Henis Y 1977 Studies on the mucilaginous layer of barley (Hordeum vulgare) roots. Plant and Soil 47, 171–191.

    Article  CAS  Google Scholar 

  8. Hoagland D R and Snyder W C 1933 Nutrition of strawberry plant under controlled conditions: (a) Effects of deficiencies of boron and certain other elements: (b) Susceptibility to injury from sodium salts. Proc. Am. Soc. Hortic. Sci. 30, 288–296.

    Google Scholar 

  9. Jensen W A 1955 A morphological and biochemical analysis of the early phases of cellular growth in the root tip ofVicia faba. Exp. Cell Res. 8, 506–522.

    Article  CAS  PubMed  Google Scholar 

  10. Martin J K 1977 Factors influencing the loss of organic carbon from wheat roots. Soil Biol. Biochem. 9, 1–7.

    CAS  Google Scholar 

  11. Nalewaja J D and Smith L H 1963 Standard procedure for the quantitative determination of individual sugars and total soluble carbohydrate materials in plant extracts. Agron. J. 55, 523–525.

    CAS  Google Scholar 

  12. Nelson D W and Sommers L E 1973 Determination of total nitrogen in plant material. Agron. J. 65, 109–112.

    CAS  Google Scholar 

  13. Nelson D W and Sommers L E 1975 Determination of total nitrogen in natural waters. J. Environ. Qual. 4, 465–468.

    CAS  Google Scholar 

  14. Neyra C A and Dobereiner J 1977 Nitrogen fixation in grasses. Adv. Agron. 29, 1–38.

    CAS  Google Scholar 

  15. Rovira A D and Campbell R 1974 Scanning electron microscopy of microorganisms on the roots of wheat. Microb. Ecol. 1, 15–23.

    Google Scholar 

  16. Smith R L, Bouton J H, Schank S C, Quesenberry K H, Tyler M E, Milam J R, Gaskins M H and Littel R C 1976 Nitrogen fixation in grasses inoculated withSpirillum lipoferum. Science 193, 1003–1005.

    CAS  Google Scholar 

  17. Tien T M, Gaskins M H and Hubbell D H 1979 Plant growth substances produced byAzopirillum brasilense and their effects on the growth of pearl millet. Appl. Microb. 37, 116–124.

    Google Scholar 

  18. Umali-Garcia M, Hubbell D H and Gaskins M H 1978 Process of infection ofPanicum maximum bySpirillum lipoferum.In Environmental Role of Nitrogen-fixing Blue-green Algae and Asymbiotic Bacteria. Ed. U Granhall. Ecol. Bull. (Stockholm) 26, 373–379.

  19. Umbreit W W, Burris R H and Stauffer J F 1972 Manometric and Biochemical Techniques (5th ed.), Burgess Publ. Co. Minneapolis Minnesota.

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Institute of Forest Genetics, Suweon, Korea

    K. J. Lee

  2. ARS, U.S. Dept. of Agriculture, University of Florida, Gainesville, Florida, USA

    M. H. Gaskins

Authors
  1. K. J. Lee
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. M. H. Gaskins
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Lee, K.J., Gaskins, M.H. Increased root exudation of14C-compounds by sorghum seedlings inoculated with nitrogen-fixing bacteria. Plant Soil 69, 391–399 (1982). https://doi.org/10.1007/BF02372460

Download citation

  • Received:

  • Revised:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF02372460

Key words

Search

Navigation