title: Nitrogen decreases and precipitation increases ectomycorrhizal extramatrical mycelia production in a longleaf pine forest.
abstract: The rates and controls of ectomycorrhizal fungal production were assessed in a 22-year-old longleaf pine (Pinus palustris Mill.) plantation using a complete factorial design that included two foliar scorching (control and 95% plus needle scorch) and two nitrogen (N) fertilization (control and 5 g N m(-2) year(-1)) treatments during an annual assessment. Ectomycorrhizal fungi production comprised of extramatrical mycelia, Hartig nets and mantles on fine root tips, and sporocarps was estimated to be 49 g m(-2) year(-1) in the control treatment plots. Extramatrical mycelia accounted for approximately 95% of the total mycorrhizal production estimate. Mycorrhizal production rates did not vary significantly among sample periods throughout the annual assessment (p = 0.1366). In addition, reduction in foliar leaf area via experimental scorching treatments did not influence mycorrhizal production (p = 0.9374), suggesting that stored carbon (C) may decouple the linkage between current photosynthate production and ectomycorrhizal fungi dynamics in this forest type. Nitrogen fertilization had a negative effect, whereas precipitation had a positive effect on mycorrhizal fungi production (p = 0.0292; r (2) = 0.42). These results support the widely speculated but poorly documented supposition that mycorrhizal fungi are a large and dynamic component of C flow and nutrient cycling dynamics in forest ecosystems.
authors.affiliation: Joseph W. Jones Ecological Research Center at Ichauway, Rt. 2, P.O. Box 2324, Newton, GA, 39870, USA. ssims@jonesctr.org.
authors.forename: Stephanie E
authors.initials: SE
authors.lastname: Sims
authors.affiliation: Department of Biology, University of West Georgia, Carrollton, GA, 30118, USA.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Hendricks
authors.affiliation: Joseph W. Jones Ecological Research Center at Ichauway, Rt. 2, P.O. Box 2324, Newton, GA, 39870, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Mitchell
authors.affiliation: Department of Biological Sciences, The University of Southern Mississippi, Hattiesburg, MS, 39406, USA.
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Kuehn
authors.affiliation: Joseph W. Jones Ecological Research Center at Ichauway, Rt. 2, P.O. Box 2324, Newton, GA, 39870, USA.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Pecot
mesh_terms: D018533:Biomass; D004784:Environmental Monitoring; D025282:Mycelium / Q000254:growth & development / Q000302:isolation & purification; D038821:Mycorrhizae / Q000254:growth & development* / Q000302:isolation & purification; D009584:Nitrogen; D028223:Pinus / Q000382:microbiology*; D011891:Rain; D014197:Trees
chemical_list: D009584:Nitrogen