Transfer of 13 C between paired Douglas-fir seedlings reveals plant kinship effects and uptake of exudates by ectomycorrhizas.
New Phytol
; 214(1): 400-411, 2017 Apr.
Article
em En
| MEDLINE
| ID: mdl-27870059
ABSTRACT
Processes governing the fixation, partitioning, and mineralization of carbon in soils are under increasing scrutiny as we develop a more comprehensive understanding of global carbon cycling. Here we examined fixation by Douglas-fir seedlings and transfer to associated ectomycorrhizal fungi, soil microbes, and full-sibling or nonsibling neighbouring seedlings. Stable isotope probing with 99% 13 C-CO2 was applied to trace 13 C-labelled photosynthate throughout plants, fungi, and soil microbes in an experiment designed to assess the effect of relatedness on 13 C transfer between plant pairs. The fixation and transfer of the 13 C label to plant, fungal, and soil microbial tissue was examined in biomass and phospholipid fatty acids. After a 6 d chase period, c. 26.8% of the 13 C remaining in the system was translocated below ground. Enrichment was proportionally greatest in ectomycorrhizal biomass. The presence of mesh barriers (0.5 or 35 µm) between seedlings did not restrict 13 C transfer. Fungi were the primary recipients of 13 C-labelled photosynthate throughout the system, representing 60-70% of total 13 C-enriched phospholipids. Full-sibling pairs exhibited significantly greater 13 C transfer to recipient roots in two of four Douglas-fir families, representing three- and fourfold increases (+ c. 4 µg excess 13 C) compared with nonsibling pairs. The existence of a root/mycorrhizal exudation-hyphal uptake pathway was supported.
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Base de dados:
MEDLINE
Assunto principal:
Isótopos de Carbono
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Pseudotsuga
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Micorrizas
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Plântula
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Exsudatos de Plantas
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article