Plant and Soil

, Volume 117, Issue 2, pp 185–193

Root-induced nitrogen mineralisation: A theoretical analysis

  • David Robinson
  • Bryan Griffiths
  • Karl Ritz
  • Ron Wheatley
Article

Abstract

The possibility is examined that carbon (C) released into the soil from a root could enhance the availability of inorganic nitrogen (N) to plants by stimulating microbial activity. The release of soluble C compounds from roots is assumed to occur by one of two general processes: cortical cell death or exudation from intact cells. On the basis of several assumptions chosen to allow maximal amounts of N mineralisation to be calculated, greater amounts of net N mineralisation are theoretically possible at realistic soil C:N ratios of bacteria are grazed by predators such as protozoa, than if bacteria alone are active. More N is mineralised when the substrate released from the root has a high C:N ratio (as in cell death) than when it is relatively N-rich. The amounts of N that a root might realistically cause to be mineralised are unlikely to account entirely for high nitrate inflow rates that have been measured experimentally. However there are circumstances in which the loss of C from roots is essential if any N is to be mineralised and obtained by plants.

Key words

carbon exudation mineralisation nitrogen rhizosphere root uptake 

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References

  1. Biondini M, Klein D A and Redente E F 1988 Carbon and nitrogen losses through root exudation byAgropyron cristatum, A. smithii andBouteloua gracilis. Soil Biol. Biochem. 20, 477–482.Google Scholar
  2. Clarholm M 1985a Possible roles for roots, bacteria, protozoa and fungi in supplying nitrogen to plants.In Ecology and Interactions in Soil: Plant, Microbes and Animals. Eds. A H Fitter, D Atkinson, D J Read and M B Usher, pp 355–365. Blackwell Scientific Publications, Oxford.Google Scholar
  3. Clarholm M 1985b Interactions of bacteria, protozoa and plants leading to mineralisation of soil nitrogen. Soil Biol. Biochem. 17, 181–187.Google Scholar
  4. Clarke A L and Barley K P 1968 The uptake of nitrogen from soils in relation to solute diffusion. Aust. J. Soil Res. 6, 75–92.Google Scholar
  5. Clarkson D T, Sanderson J and Russell R S 1968 Ion uptake and root age. Nature 220, 805–806.Google Scholar
  6. Elliott E T, Coleman D C and Cole C V 1979 The influence of amoebae on the uptake of nitrogen by plants in gnotobiotic soil.In The Soil-Root Interface. Eds. J L Harley and R S Russell. pp 221–229. Academic Press, London.Google Scholar
  7. Elliott E T, Cole C V, Fairbanks B C, Woods L E, Bryant R J and Coleman D C 1983 Short-term bacterial growth, nutrient uptake, and ATP turnover in sterilized, inoculated and C-amended soil: The influence of N availability. Soil Biol. Biochem. 15, 85–91.Google Scholar
  8. Fusseder A 1987 The longevity and activity of the primary root of maize. Plant and Soil 101, 257–265.Google Scholar
  9. Gillespie I M M and Deacon J W 1988 Effects of mineral nutrients on senescence of the cortex of wheat roots and root pieces. Soil Biol. Biochem. 20, 525–531.Google Scholar
  10. Habib R 1988 Total root length as estimated from small subsamples. Plant and Soil 108, 267–274.Google Scholar
  11. Hunt H W, Cole C V, Klein D A and Coleman D C 1977 A simulation model for the effect of predation on bacteria in continuous culture. Microb. Ecol. 3, 259–278.Google Scholar
  12. Hunt H W, Coleman, D C, Ingham E R, Ingham R E, Elliott E T, Moore J C, Rose S L, Reid C P P and Morley C R 1987 The detrital food web in a short-grass prairie. Biol. Fertil. Soils 3, 57–68.Google Scholar
  13. Hunt R 1982 Plant Growth Curves: The Functional Approach to Plant Growth Analysis. Edward Arnold, London.Google Scholar
  14. Ingham R E, Trofymow J A, Ingham E R and Coleman D C 1985 Interactions of bacteria, fungi and their nematode grazers: Effects on nutrient cycling and plant growth. Ecol. Monogr. 55, 119–140.Google Scholar
  15. Jarvis S C 1987 The effects of low, regulated supplies of nitrate and ammonium nitrogen on the growth and composition of perennial ryegrass. Plant and Soil 100, 99–112.Google Scholar
  16. Jenkinson D S 1988 Soil organic matter and its dynamics.In Russell's Soil Conditions and Plant Growth, 11th ed. Ed. A Wild, pp 564–607. Longman, London.Google Scholar
  17. Jupp A P and Newman E I 1987 Phosphorus uptake from soil byLolium perenne during and after severe drought. J. Appl. Ecol. 24, 979–990.Google Scholar
  18. Klemmedtsson L, Berg P, Clarholm M, Schnürer J and Rosswall T 1987 Microbial nitrogen transformations in the root environment of barley. Soil Biol. Biochem. 19, 551–558.Google Scholar
  19. Lambers H 1987 Growth, respiration, exudation and symbiotic associations: The fate of carbon translocated to the roots.In Root Development and Function. Eds. P J Gregory, J V Lake and D A Rose. pp 125–145. Cambridge University Press, Cambridge.Google Scholar
  20. Newman E I 1985 The rhizosphere: Carbon sources and microbial populations.In Ecological Interactions in Soil. Ed. A H Fitter. pp 107–121. Blackwell Scientific Publications, Oxford.Google Scholar
  21. Newman E I and Watson A 1977 Microbial abundance in the rhizosphere: A computer model. Plant and Soil 48, 17–56.Google Scholar
  22. Riha S J, Campbell G S and Wolfe J 1986 A model of competition for ammonium among heterotrophs, nitrifiers and roots. Soil Sci. Soc. Am. J. 50, 1463–1466.Google Scholar
  23. Ritz K and Griffiths B S 1987 Effects of carbon and nitrate additions to soil upon leaching of nitrate, microbial predators and nitrogen uptake by plants. Plant and Soil 102 229–237.Google Scholar
  24. Robinson D and Rorison I H 1983 A comparison of the responses ofLolium perenne L.,Holcus lanatus L. andDeschampsia flexuosa (L.) Trin. to a localised supply of nitrogen. New Phytol. 93, 263–273.Google Scholar
  25. Stout J D 1980 The role of protozoa in nutrient cycling and energy flow. Adv. Microb. Ecol. 4, 1–50.Google Scholar
  26. Trofymow J A, Coleman D C and Cambardella C 1987 Rates of rhizodeposition and ammonium depletion in the rhizosphere of axenic oat roots. Plant and Soil 97, 333–344.Google Scholar
  27. Van Veen J A and Paul E A 1979 Conversion of biovolume measurements of soil organisms, grown under various moisture tensions, to biomass and their nutrient contents. Appl. Environ. Microbiol. 37, 686–692.Google Scholar
  28. Ward D and Woolhouse H W 1986 Comparative effects of light during growth on the photosynthetic properties of NADPME type C4 grasses from open and shaded habitats. I. Gas exchange, leaf anatomy and ultrastructure. Plant, Cell and Environ. 9, 261–270.Google Scholar
  29. Wood P M 1986 Nitrification as a bacterial energy source.In Nitrification. Ed. J I Prosser. pp 39–62. IRL Press, Oxford.Google Scholar

Copyright information

© Kluwer Academic Publishers 1989

Authors and Affiliations

  • David Robinson
    • 1
  • Bryan Griffiths
    • 2
  • Karl Ritz
    • 3
  • Ron Wheatley
    • 3
  1. 1.Department of Physiology and Crop ProductionScottish Crop Research InstituteDundeeUK
  2. 2.Department of ZoologyScottish Crop Research InstituteDundeeUK
  3. 3.Department of Mycology and BacteriologyScottish Crop Research InstituteDundeeUK

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