Plant and Soil

, Volume 71, Issue 1, pp 415–431

Nitrogen nutrition, photosynthesis and carbon allocation in ectomycorrhizal pine

  • C. P. P. Reid
  • F. A. Kidd
  • S. A. Ekwebelam
Article

DOI: 10.1007/BF02182683

Cite this article as:
Reid, C.P.P., Kidd, F.A. & Ekwebelam, S.A. Plant Soil (1983) 71: 415. doi:10.1007/BF02182683
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Summary

Studies examined net photosynthesis (Pn) and dry matter production of mycorrhizal and nonmycorrhizalPinus taeda at 6 intervals over a 10-month period. Pn rates of mycorrhizal plants were consistently greater than nonmycorrhizal plants, and at 10 months were 2.1-fold greater. Partitioning of current photosynthate was examined by pulse-labelling with14CO2 at each of the six time intervals. Mycorrhizal plants assimilated more14CO2, allocated a greater percentage of assimilated14C to the root systems, and lost a greater percentage of14C by root respiration than did nonmycorrhizal plants. At 10 months, the quantity of14CO2 respired by roots per unit root weight was 3.6-fold greater by mycorrhizal than nonmycorrhizal plants. Although the stimulation of photosynthesis and translocation of current photosynthate to the root system by mycorrhiza formation was consistent with the source-sink concept of sink demand, foliar N and P concentrations were also greater in mycorrhizal plants.

Further studies examined Pn and dry matter production ofPinus contorta in response to various combinations of N fertilization (3, 62, 248 ppm), irradiance and mycorrhizal fungi inoculation. At 16 weeks of age, 6 weeks following inoculation with eitherPisolithus tinctorius orSuillus granulatus, Pn rates and biomass were significantly greater in mycorrhizal than nonmycorrhizal plants. Mycorrhizal plants had significantly greater foliar %P, but not %N, than did nonmycorrhizal plants. Fertilization with 62 ppm N resulted in greater mycorrhiza formation than either 3 or 248 ppm. Increased irradiance resulted in increased mycorrhiza formation.

Key words

Carbon allocationLight MycorrhizasNitrogenPhosphorusPhotosynthesisPinus contortaPinus taedaPisolithus tinctoriusRespirationSource-sinkSuillus granulatus

Copyright information

© Martinus Nijhoff/Dr W. Junk Publishers 1983

Authors and Affiliations

  • C. P. P. Reid
    • 1
  • F. A. Kidd
    • 1
  • S. A. Ekwebelam
    • 1
  1. 1.Department of Forest and Wood SciencesColorado State UniversityFort CollinsUSA
  2. 2.Potlatch CorporationLewistonUSA
  3. 3.Savanna Forestry Research StationSamaru-ZariaNigeria