Abstract
The vast majority of terrestrial plants form root symbioses with arbuscular mycorrhizal (AM) fungi to enhance nutrient (particularly phosphorus, P) acquisition. However, some plant species also form dual symbioses involving ectomycorrhizal (ECM) fungi, with a subset of those also forming triple symbioses also involving dinitrogen (N-2)-fixing bacteria. It has been suggested that these plants show plasticity in root symbioses to optimise nutrient acquisition depending on the type and strength of soil nutrient limitation (e.g., N vs. P), yet empirical evidence remains limited. Alternatively, the degree of investment or "preference" in particular root symbioses might simply reflect differences in inoculum potential among soils of contrasting nutrient availability, reflecting adaptations of root symbionts to different edaphic conditions. Here, we grew two co-occurring plant species forming triple (AM/ECM/N-2-fixing; Acacia rostellifera) or dual (AM/ECM; Melaleuca systena) symbioses in soils of increasing age and contrasting nutrient availability from an Australian long-term soil chronosequence to disentangle the relative importance of abiotic factors (e.g., soil nutrient availability and stoichiometry) and biotic factors (e.g., soil inoculum potential) in determining root colonisation patterns and functional outcomes of these multiple root symbioses. For both plant species, we found clear hump-shaped plant growth patterns along the pedogenesis-driven gradient in soil nutrient availability, with peak growth in intermediate-aged soils, while high levels of mycorrhizal colonisation by the "preferred" root symbionts were maintained across all soils. We found large increases (540%) in foliar manganese concentrations with increasing soil age and declining P availability, suggesting that plants may be relying on the release of carboxylates to help acquire P in the most P-impoverished soils. Finally, we found that soil abiotic properties, such as strong differences in soil nutrient availability, are generally more important than soil inoculum potential in explaining these shifts in our plant and root responses. Synthesis. Our study suggests that plants capable of forming multiple root symbioses show plasticity in their nutrient-acquisition strategies following shifts in soil nutrients during long-term ecosystem development, yet maintain a preference for certain root symbionts despite changes in soil microbial inoculum.
| Original language | English |
|---|---|
| Pages (from-to) | 633-649 |
| Number of pages | 17 |
| Journal | Journal of Ecology |
| Volume | 107 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Mar 2019 |
Cite this
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Plasticity in root symbioses following shifts in soil nutrient availability during long-term ecosystem development. / Teste, Francois P.; Laliberte, Etienne.
In: Journal of Ecology, Vol. 107, No. 2, 03.2019, p. 633-649.Research output: Contribution to journal › Article
TY - JOUR
T1 - Plasticity in root symbioses following shifts in soil nutrient availability during long-term ecosystem development
AU - Teste, Francois P.
AU - Laliberte, Etienne
PY - 2019/3
Y1 - 2019/3
N2 - The vast majority of terrestrial plants form root symbioses with arbuscular mycorrhizal (AM) fungi to enhance nutrient (particularly phosphorus, P) acquisition. However, some plant species also form dual symbioses involving ectomycorrhizal (ECM) fungi, with a subset of those also forming triple symbioses also involving dinitrogen (N-2)-fixing bacteria. It has been suggested that these plants show plasticity in root symbioses to optimise nutrient acquisition depending on the type and strength of soil nutrient limitation (e.g., N vs. P), yet empirical evidence remains limited. Alternatively, the degree of investment or "preference" in particular root symbioses might simply reflect differences in inoculum potential among soils of contrasting nutrient availability, reflecting adaptations of root symbionts to different edaphic conditions. Here, we grew two co-occurring plant species forming triple (AM/ECM/N-2-fixing; Acacia rostellifera) or dual (AM/ECM; Melaleuca systena) symbioses in soils of increasing age and contrasting nutrient availability from an Australian long-term soil chronosequence to disentangle the relative importance of abiotic factors (e.g., soil nutrient availability and stoichiometry) and biotic factors (e.g., soil inoculum potential) in determining root colonisation patterns and functional outcomes of these multiple root symbioses. For both plant species, we found clear hump-shaped plant growth patterns along the pedogenesis-driven gradient in soil nutrient availability, with peak growth in intermediate-aged soils, while high levels of mycorrhizal colonisation by the "preferred" root symbionts were maintained across all soils. We found large increases (540%) in foliar manganese concentrations with increasing soil age and declining P availability, suggesting that plants may be relying on the release of carboxylates to help acquire P in the most P-impoverished soils. Finally, we found that soil abiotic properties, such as strong differences in soil nutrient availability, are generally more important than soil inoculum potential in explaining these shifts in our plant and root responses. Synthesis. Our study suggests that plants capable of forming multiple root symbioses show plasticity in their nutrient-acquisition strategies following shifts in soil nutrients during long-term ecosystem development, yet maintain a preference for certain root symbionts despite changes in soil microbial inoculum.
AB - The vast majority of terrestrial plants form root symbioses with arbuscular mycorrhizal (AM) fungi to enhance nutrient (particularly phosphorus, P) acquisition. However, some plant species also form dual symbioses involving ectomycorrhizal (ECM) fungi, with a subset of those also forming triple symbioses also involving dinitrogen (N-2)-fixing bacteria. It has been suggested that these plants show plasticity in root symbioses to optimise nutrient acquisition depending on the type and strength of soil nutrient limitation (e.g., N vs. P), yet empirical evidence remains limited. Alternatively, the degree of investment or "preference" in particular root symbioses might simply reflect differences in inoculum potential among soils of contrasting nutrient availability, reflecting adaptations of root symbionts to different edaphic conditions. Here, we grew two co-occurring plant species forming triple (AM/ECM/N-2-fixing; Acacia rostellifera) or dual (AM/ECM; Melaleuca systena) symbioses in soils of increasing age and contrasting nutrient availability from an Australian long-term soil chronosequence to disentangle the relative importance of abiotic factors (e.g., soil nutrient availability and stoichiometry) and biotic factors (e.g., soil inoculum potential) in determining root colonisation patterns and functional outcomes of these multiple root symbioses. For both plant species, we found clear hump-shaped plant growth patterns along the pedogenesis-driven gradient in soil nutrient availability, with peak growth in intermediate-aged soils, while high levels of mycorrhizal colonisation by the "preferred" root symbionts were maintained across all soils. We found large increases (540%) in foliar manganese concentrations with increasing soil age and declining P availability, suggesting that plants may be relying on the release of carboxylates to help acquire P in the most P-impoverished soils. Finally, we found that soil abiotic properties, such as strong differences in soil nutrient availability, are generally more important than soil inoculum potential in explaining these shifts in our plant and root responses. Synthesis. Our study suggests that plants capable of forming multiple root symbioses show plasticity in their nutrient-acquisition strategies following shifts in soil nutrients during long-term ecosystem development, yet maintain a preference for certain root symbionts despite changes in soil microbial inoculum.
KW - ecosystem development and retrogression
KW - foliar manganese
KW - mycorrhizal fungi
KW - nitrogen and phosphorus limitation
KW - nutrient-acquisition strategies
KW - poor and deficient soil
KW - root traits
KW - ARBUSCULAR MYCORRHIZAL INFECTION
KW - FUNGAL COMMUNITY COMPOSITION
KW - N-15 NATURAL-ABUNDANCE
KW - ECTOMYCORRHIZAL FUNGI
KW - ACQUISITION STRATEGIES
KW - PINUS-MURICATA
KW - PLANT
KW - PHOSPHORUS
KW - ASSOCIATIONS
KW - DIVERSITY
U2 - 10.1111/1365-2745.13103
DO - 10.1111/1365-2745.13103
M3 - Article
VL - 107
SP - 633
EP - 649
JO - Journal of Ecology
JF - Journal of Ecology
SN - 0022-0477
IS - 2
ER -