title: Effect of raw humus under two adult Scots pine stands on ectomycorrhization, nutritional status, nitrogen uptake, phosphorus uptake and growth of Pinus sylvestris seedlings.
abstract: Ectomycorrhiza (EM) formation improves tree growth and nutrient acquisition, particularly that of nitrogen (N). Few studies have coupled the effects of naturally occurring EM morphotypes to the nutrition of host trees. To investigate this, pine seedlings were grown on raw humus substrates collected at two forest sites, R2 and R3. Ectomycorrhiza morphotypes were identified, and their respective N uptake rates from organic (2-(13)C, (15)N-glycine) and inorganic ((15)NH(4)Cl, Na(15)NO(3), (15)NH(4)NO(3), NH(4)(15)NO(3)) sources as well as their phosphate uptake rates were determined. Subsequently, the growth and nutritional status of the seedlings were analyzed. Two dominant EM morphotypes displayed significantly different mycorrhization rates in the two substrates. Rhizopogon luteolus Fr. (RL) was dominant in R2 and Suillus bovinus (Pers.) Kuntze (SB) was dominant in R3. (15)N uptake of RL EM was at all times higher than that of SB EM. Phosphate uptake rates by the EM morphotypes did not differ significantly. The number of RL EM correlated negatively and the number of SB EM correlated positively with pine growth rate. Increased arginine concentrations and critical P/N ratios in needles indicated nutrient imbalances of pine seedlings from humus R2, predominantly mycorrhizal with RL. We conclude that different N supply in raw humus under Scots pine stands can induce shifts in the EM frequency of pine seedlings, and this may lead to EM formation by fungal strains with different ability to support tree growth.
authors.affiliation: Department of Soil Ecology, UFZ-Helmholtz Centre for Environmental Research, Theodor-Lieser-Strasse 4, 6120 Halle (Saale), Germany. horst.schulz@ufz.de
authors.forename: Horst
authors.initials: H
authors.lastname: Schulz
authors.forename: Tina
authors.initials: T
authors.lastname: Schäfer
authors.forename: Veronika
authors.initials: V
authors.lastname: Storbeck
authors.forename: Sigrid
authors.initials: S
authors.lastname: Härtling
authors.forename: Renate
authors.initials: R
authors.lastname: Rudloff
authors.forename: Margret
authors.initials: M
authors.lastname: Köck
authors.forename: François
authors.initials: F
authors.lastname: Buscot
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D001120:Arginine / Q000378:metabolism; D001487:Basidiomycota / Q000254:growth & development; D015169:Colony Count, Microbial; D005858:Germany; D038821:Mycorrhizae / Q000254:growth & development / Q000502:physiology*; D050901:Nitrate Reductase / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D009587:Nitrogen Isotopes; D010710:Phosphates / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism*; D010759:Phosphorus Isotopes; D041605:Pinus sylvestris / Q000201:enzymology / Q000254:growth & development* / Q000382:microbiology*; D018515:Plant Leaves / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D036226:Seedlings / Q000254:growth & development* / Q000382:microbiology; D012987:Soil / Q000737:chemistry*; D012995:Solubility; D013997:Time Factors
chemical_list: D000596:Amino Acids; D009587:Nitrogen Isotopes; D010710:Phosphates; D010759:Phosphorus Isotopes; D000644:Quaternary Ammonium Compounds; D012987:Soil; D010758:Phosphorus; D001120:Arginine; D050901:Nitrate Reductase; D009584:Nitrogen