A possible role for saprotrophic microfungi in the N nutrition of ectomycorrhizal Pinus resinosa

• Published in: Soil biology & biochemistry Vol. 37; no. 5; pp. 965 - 975
• Main Authors: Wu, T., Kabir, Z., Koide, R.T.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.05.2005; New York, NY Elsevier Science
• Subjects: Agronomy. Soil science and plant productions; Amino acids; Biochemistry and biology; Biological and medical sciences; carbon nitrogen ratio; Chemical, physicochemical, biochemical and biological properties; Economic plant physiology; ectomycorrhizae; Ectomycorrhizal fungi; forest soils; forest trees; Fundamental and applied biological sciences. Psychology; Glucosamine; mineralization; mycorrhizal fungi; nitrogen; nutrient availability; Organic nitrogen; Penicillium; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Pinus resinosa; Pisolithus tinctorius; Polyphenol; Protein; saprophytes; Saprotrophic microfungi; soil fungi; Soil science; Suillus; Symbiosis (nodules, symbiotic nitrogen fixation, mycorrhiza...); Trichoderma; trophic relationships; Glucosamine; Organic nitrogen; Pinus resinosa; Polyphenol; Saprotrophic microfungi; Amino acids; Protein; Ectomycorrhizal fungi; Nutrition; Glucosamine; Organic nitrogen; Symbiont; Saprobiosis; Fungi; resinosa; Polyphenol; Aminoacid; Softwood forest tree; Gymnospermae; Mycorrhiza; Ammo acids; Ectomycorrhizal fungi; Ectomycorrhiza; Coniferales; Spermatophyta; Soil science; Pinm; Thallophyta
• ISSN: 0038-0717; 1879-3428
• DOI: 10.1016/j.soilbio.2004.10.015

We determined whether Pinus resinosa, selected ectomycorrhizal and saprotrophic microfungi have access to various organic nitrogen sources commonly found in the forest. Vector analysis demonstrated nitrogen limitation of the P. resinosa in the plantation from which most of the fungi were isolated, establishing this study's relevance. Nonmycorrhizal P. resinosa seedlings did not absorb significant N from amino acids. The ectomycorrhizal fungi, including Pisolithus tinctorius, Suillus intermedius and Tylopilus felleus, obtained substantial N from amino acids, a limited amount of N from glucosamine, and essentially no N from protein–tannin complex. In contrast, Penicillium and Trichoderma readily acquired N from protein–tannin and glucosamine. Thus, there was an increasing ability to obtain N from complex organic N sources from plant to ectomycorrhizal fungi to saprotrophic fungi. Furthermore, N mineralization from an organic N source by Penicillium depended on the C:N ratio. We conclude that acquisition of relatively simple organic N sources by P. resinosa is likely to be largely indirect via ectomycorrhizal fungi, and that more complex organic N sources may become accessible to ectomycorrhizal fungi (and thus possibly their host plants) following mineralization by saprotrophic fungi such as Penicillium or Trichoderma when C:N ratios are sufficiently low.