Record ID No. |
2390 |
Author(s) |
Michael F. Allen; Edith B. Allen; Jennifer L. Lansing; Kurt S. Pregitzer; Ron L. Hendrick; Roger W. Ruess; Scott L. Collins , 2010 |
Affiliation |
Center forConservationBiology,UniversityofCalifornia,Riverside,CA92521,USA, E-mail: michael.allen@ucr.edu |
Title |
Responses to chronic N fertilization of ectomycorrhizal piņon but not arbuscular mycorrhizal juniper in a piņon-juniper woodland |
Source. Vol.(no):Page |
Journal of Arid Environments, 1-7p. |
Categories |
Mycorrhiza General |
Subjects |
Soil plant relations |
Sub-subjects |
Fungal evaluation |
Host |
Trees(Juniper, Pine) |
Organism |
EMF, AMF |
Country |
USA., N. America |
Abstracts |
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 piņon-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) piņon but not in arbuscular mycorrhizal (AM) juniper. Based on N fractionation between EM fungal sporocarps and piņon, EM in piņon utilized 20% of the net primary production in control plots. No sporocarps were produced in fertilized plots. N uptake by piņon could be accounted for by fertilization without mycorrhizae. Leaf N and size increased with fertilization in both species, and positively correlated with leaf δ 13 C. Leaf N:P increased in piņon but not juniper. Piņon 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 piņon production and mortality in semi-arid woodlands in the western US. |