Summary
Transport of N by hyphae of a vesicular-arbuscular mycorrhizal fungus was studied under controlled experimental conditions. The N source was applied to the soil as 15NH sup+inf4 or 15NO sup-inf3 . Cucumis sativus was grown for 25 days, either alone or in symbiosis with Glomus intraradices, in containers with a hyphal compartment separated from the root compartment by a fine nylon mesh. Mineral N was then applied to the hyphal compartment as 15NH sup+inf4 or 15NO sup-inf3 at 5 cm distance from the root compartment. Soil samples were taken from the hyphal compartment at 1, 3 and 5 cm distance from the root compartment at 7 and 12 days after labelling, and the concentration of mineral N in the samples was measured from 2 M KCl extracts. Mycorrhizal colonization did not affect plant dry weight. The recovery of 15N in mycorrhizal plants was 38 or 40%, respectively, when 15NH sup+inf4 or 15NO sup-inf3 was applied. The corresponding values for non-mycorrhizal plants were 7 and 16%. The higher 15N recovery observed in mycorrhizal plants than in non-mycorrhizal plants suggests that hyphal transport of N from the applied 15N sources towards the host plant had occurred. The concentration of mineral N in the soil of hyphal compartments was considerably less in mycorrhizal treatments than in controls, indicating that the hyphae were able to deplete the soil for mineral N.
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Johansen, A., Jakobsen, I. & Jensen, E.S. Hyphal transport by a vesicular-arbuscular mycorrhizal fungus of N applied to the soil as ammonium or nitrate. Biol Fertil Soils 16, 66–70 (1993). https://doi.org/10.1007/BF00336518
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DOI: https://doi.org/10.1007/BF00336518