Record ID No. |
1502 |
Author(s) |
Stackpoole, SM; Workmaster, BAA; Jackson, RD; Kosola KR. , 2008 |
Affiliation |
Stackpoole SM, Univ Wisconsin, Madison Hort Dept, 1575 Linden Dr, Madison,WI 53706 USA |
Title |
Nitrogen conservation strategies of cranberry plants and ericoid mycorrhizal fungi in an agroecosystem |
Source. Vol.(no):Page |
Soil Biology & Biochemistry, 40(11): 2736-2742 |
Categories |
Ericoid Mycorrhiza |
Subjects |
Biochemistry |
Sub-subjects |
Miscellaneous |
Abstracts |
Ericoid mycorrhizal fungi (ERM) are ubiquitous in cultivated cranberry beds, but no prior studies have used N-15 natural abundance measurements to track ERM influence on nitrogen (N) cycling in these agroecosystems. Cranberries (Vaccinium macrocarpon) evolved in low-nutrient peat bogs, and ERM symbioses often occur in nutrient-poor environments where N is limiting. We investigated ERM symbiosis, resorption rates, as well as leaf litter quality and decomposition to infer N conservation strategies in cultivated cranberry plants. We expected moderate to high resorption rates and low leaf litter decomposition rates. We also expected to find evidence of ERM fungi mediating N uptake. Resorption rates (35.7 +/- 3.5% [s.e.]) were moderate, and the resulting cranberry leaf litter had high C:N ratios (56.9 +/- 0.02). Decomposition was slow with 57 +/- 2% of initial leaf litter mass remaining at the end of 2.5 years. The negative delta N-15 values of cranberry leaves (-2.61 0.27 parts per thousand) and positive delta N-15 values of cranberry roots (1.04 +/- 0.35 parts per thousand) suggest that N uptake was mediated by ERM fungi as N-14 is preferred over N-15 during transfer from mycorrhizal fungi to host plant. We demonstrated that even in this intensively managed and fertilized agroecosystem, cranberry plants retain N conservation strategies observed in wildland cranberry ecosystems, namely high resorption efficiencies, low-quality leaf litter, and active ERM symbiosis. This study has management implications, since current nutrient plans mainly focus on inorganic N fertilizer regulation and do not recognize the role of ERM fungi in mediating N uptake. (c) 2008 Elsevier Ltd. All rights reserved. |