Integrating plant carbon dynamics with mutualism ecology

Summary Plants reward microbial and animal mutualists with carbohydrates to obtain nutrients, defense, pollination, and dispersal. Under a fixed carbon budget, plants must allocate carbon to their mutualists at the expense of allocation to growth, reproduction, or storage. Such carbon trade‐offs are indirectly expressed when a plant exhibits reduced growth or fecundity in the presence of its mutualist. Because carbon regulates the costs of all plant mutualisms, carbon dynamics are a common platform for integrating these costs in the face of ecological complexity and context dependence. The ecophysiology of whole‐plant carbon allocation could thus elucidate the ecology and evolution of plant mutualisms. If mutualisms are costly to plants, then they must be important but frequently underestimated sinks in the terrestrial carbon cycle.ContentsSummary 71 I. Introduction 71 II. The carbon dynamics of plant mutualisms 72 III. Tracking carbon allocation to mutualism 73 IV. Mutualisms and the global carbon cycle 74 V. Conclusions 74Acknowledgements 74References 74