التفاصيل البيبلوغرافية
| العنوان: |
Responses to chronic N fertilization of ectomycorrhizal piñon but not arbuscular mycorrhizal juniper in a piñon-juniper woodland |
| المؤلفون: |
Allen, Michael F.1 michael.allen@ucr.edu, Allen, Edith B.1, Lansing, Jennifer L.1, Pregitzer, Kurt S.2, Hendrick, Ron L.3, Ruess, Roger W.4, Collins, Scott L.5 |
| المصدر: |
Journal of Arid Environments. Oct2010, Vol. 74 Issue 10, p1170-1176. 7p. |
| مصطلحات موضوعية: |
*JUNIPERS, *NITROGEN fertilizers, *PITCH pine, *PLANT mortality, *ECTOMYCORRHIZAS, *EFFECT of drought on plants, *FOREST plants, *FORESTS & forestry |
| مصطلحات جغرافية: |
NEW Mexico |
| مستخلص: |
Abstract: Responses of mature trees to chronic N additions are poorly understood in ecosystems with high seasonal and spatial variability. To determine the effects of increased N deposition on mature conifers, we fertilized a piñon-juniper woodland in New Mexico at a rate equivalent to the urban interface. Fertilization (10 g m−2 y−1) reduced numbers of mycorrhizae and increased leaf production in the ectomycorrhizal (EM) piñon but not in arbuscular mycorrhizal (AM) juniper. Based on N fractionation between EM fungal sporocarps and piñon, EM in piñon utilized 20% of the net primary production in control plots. No sporocarps were produced in fertilized plots. N uptake by piñon could be accounted for by fertilization without mycorrhizae. Leaf N and size increased with fertilization in both species, and positively correlated with leaf δ13C. Leaf N:P increased in piñon but not juniper. Piñon mortality commenced in the N-fertilized plots in 2001, a year before the widespread die-off in western conifers, and continued through 2003. No mortality was observed in control plots or in junipers. The coupling of N enrichment and mycorrhizal decline could affect piñon production and mortality in semi-arid woodlands in the western US. [Copyright &y& Elsevier] |
| قاعدة البيانات: |
Academic Search Index |
