Plant preferential allocation and fungal reward decline with soil phosphorus: implications for mycorrhizal mutualism

View/ Open
Issue Date
2016-05-25Author
Ji, Baoming
Bever, James D.
Publisher
Ecological Society of America
Type
Article
Article Version
Scholarly/refereed, publisher version
Rights
© 2016 Ji and Bever. This is an open access article under the terms of the Creative Commons Attribution
License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Metadata
Show full item recordAbstract
Explaining the persistence of mutualism remains a challenge in ecology and evolutionary biology. The evolutionary stability of arbuscular mycorrhiza, a most widespread and ancient mutualistic association, is particularly intriguing because plants lack apparent mechanisms to prevent cheaters from gaining competitive advantages over cooperators. We developed a triple isotopic labeling method (14C, 32P, and 33P) within a split-root design to measure the exchange of carbon (C) and phosphorus (P) between the host plant and two mycorrhizal partners across a soil P gradient. Host plant preferentially allocated more C to the roots associated with the fungus delivering higher P per unit plant C, and the strength of preferential allocation decreased with increasing soil P availability. The host plant received more P per unit of allocated C from the better fungus and this advantageous exchange rate did not depend upon P availability. As a result, the level of preferential allocation was correlated with the differential delivery of P from the two fungi. Our findings suggest that plant preferential allocation to better mutualists can stabilize mutualisms in environments limiting in the traded resource, but as the availability of this resource increases, plant preferential allocation declines. This environmental dependence of preferential allocation generates predictions of declining levels in relative abundance of mutualistic fungi in high-resource environments.
Collections
Citation
Ji, B., and J. D. Bever. 2016. Plant preferential allocation and fungal reward decline with soil phosphorus:
implications for mycorrhizal mutualism. Ecosphere 7(5):e01256. 10.1002/ecs2.1256
Items in KU ScholarWorks are protected by copyright, with all rights reserved, unless otherwise indicated.
We want to hear from you! Please share your stories about how Open Access to this item benefits YOU.