Mycorrhizal associations of temperate forest seedlings mediate rhizodeposition, but not soil carbon storage, under elevated nitrogen availability.
Glob Chang Biol
; 30(8): e17446, 2024 Aug.
Article
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| MEDLINE
| ID: mdl-39109391
ABSTRACT
Tree-mycorrhizal associations are associated with patterns in nitrogen (N) availability and soil organic matter storage; however, we still lack a mechanistic understanding of what tree and fungal traits drive these patterns and how they will respond to global changes in soil N availability. To address this knowledge gap, we investigated how arbuscular mycorrhizal (AM)- and ectomycorrhizal (EcM)-associated seedlings alter rhizodeposition in response to increased seedling inorganic N acquisition. We grew four species each of EcM and AM seedlings from forests of the eastern United States in a continuously 13C-labeled atmosphere within an environmentally controlled chamber and subjected to three levels of 15N-labeled fertilizer. We traced seedling 15N uptake from, and 13C-labeled inputs (net rhizodeposition) into, root-excluded or -included soil over a 5-month growing season. N uptake by seedlings was positively related to rhizodeposition for EcM- but not AM-associated seedlings in root-included soils. Despite this contrast in rhizodeposition, there was no difference in soil C storage between mycorrhizal types over the course of the experiment. Instead root-inclusive soils lost C, while root-exclusive soils gained C. Our findings suggest that mycorrhizal associations mediate tree belowground C investment in response to inorganic N availability, but these differences do not affect C storage. Continued soil warming and N deposition under global change will increase soil inorganic N availability and our seedling results indicate this could lead to greater belowground C investment by EcM-associated trees. This potential for less efficient N uptake by EcM-trees could contribute to AM-tree success and a shift toward more AM-dominated temperate forests.
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Texto completo:
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Bases de datos:
MEDLINE
Asunto principal:
Suelo
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Carbono
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Bosques
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Micorrizas
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Plantones
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Nitrógeno
Idioma:
En
Revista:
Glob Chang Biol
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Glob. chang. biol
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Global change biology
Año:
2024
Tipo del documento:
Article
País de afiliación:
Estados Unidos