A carregar...
PublicaĆ§Ć£o
Testing the tradeābalance model: resource stoichiometry does not sufficiently explain AM effects
| Nome: | DescriĆ§Ć£o: | Tamanho: | Formato: | |
|---|---|---|---|---|
| 1.39 MB | Adobe PDF |
Autores
Orientador(es)
Resumo(s)
Variations in arbuscular mycorrhizae (AM) effects on plant growth (MGR) are commonly assumed to result from costā:ābenefit balances, with C as the cost and, most frequently, P as the benefit. The trade-balance model (TBM) adopts these assumptions and hypothesizes that mycorrhizal benefit depends on Cā:āNā:āP stoichiometry. Although widely accepted, the TBM has not been experimentally tested.
We isolated the parameters included in the TBM and tested these assumptions using it as framework. Oryza sativa plants were supplied with different Nā:āP ratios at low light level, establishing different Cā:āP and Cā:āN exchange rates, and C, N or P limitation. MGR and effects on nutrient uptake, %M, ERM, photosynthesis and shoot starch were measured.
C distribution to AM fungi played no role in MGR, and N was essential for all AM effects, including on P nutrition. C distribution to AM and MGR varied with the limiting nutrient (N or P), and evidence of extensive interplay between N and P was observed.
The TBM was not confirmed. The results agreed with the exchange of surplus resources and sourceāsink regulation of resource distribution among plants and AMF. Rather than depending on exchange rates, resource exchange may simply obey both symbiont needs, not requiring further regulation.
DescriĆ§Ć£o
Palavras-chave
Trade balance model, arbuscular mycorrhiza, nutrient stoichiometry, surplus resources, N, P, C, cost:benefit balance
Contexto Educativo
CitaĆ§Ć£o
Editora
Wiley