Plant performance was greater in the soils of more distantly related plants for an herbaceous understory species.

Drake D Sweet,Jean H Burns

doi:10.1093/aobpla/plx005

Abstract

Growing evidence suggests that plant-soil interactions have important implications for plant community composition. However, the role of phylogenetic relatedness in governing interactions between plants and soil biota is unclear, and more case studies are needed to help build a general picture of whether and how phylogeny might influence plant-soil interactions. We performed a glasshouse experiment to test whether degree of phylogenetic relatedness between Aquilegia canadensis and six co-occurring heterospecifics affects A. canadensis biomass through soil legacy effects. We also compared performance of A. canadensis in soils conditioned by invasive Alliaria petiolata versus native heterospecifics, hypothesizing that conditioning by A. petiolata would suppress the performance of the focal native plant. A. canadensis performed significantly better in distant relatives' soils than in close relatives' soils, and this effect disappeared with soil sterilization, consistent with close relatives sharing similar pathogens. Contrary to our expectations, soils conditioned by the invasive species A. petiolata versus by native species had similar effects on A. canadensis. The greater performance of A. canadensis in soils of more versus less distant relatives is consistent with a hypothesis of phylogenetically constrained pathogen escape, a phenomenon expected to promote coexistence of phylogenetically distant species. However, pairwise plant-soil feedback experiments are needed to create a stronger coexistence prediction.

Highlights

Recent evidence suggests that plant community diversity is influenced by plant–soil feedbacks (PSFs) and soil legacy effects, where plants alter the performance of the plant to grow in a given patch of soil (Kulmatiski et al 2008; Bever et al 2010, 2015)
A. canadensis plant performance was greater in soils conditioned by more distant relatives, both when phylogenetic distances were based on a molecular phylogram (P 1⁄4 0.09, Fig. 2, Table 1) or on a phyloGenerator ultrametric phylogeny (P 1⁄4 0.04, Table 1)
When the invasive conditioning species A. petiolata was excluded from these Mantel tests, phylogenetic distance still correlated positively with A. canadensis biomass in live soils (Pearson correlation coefficient r 1⁄4 0.18, P 1⁄4 0.047) and again did not correlate with A. canadensis biomass in sterilized soils (Pearson correlation coefficient r 1⁄4 0.03, P 1⁄4 0.36)

Summary

Introduction

Recent evidence suggests that plant community diversity is influenced by plant–soil feedbacks (PSFs) and soil legacy effects, where plants alter the performance of the plant to grow in a given patch of soil (Kulmatiski et al 2008; Bever et al 2010, 2015). Plant-soil interactions are likely to be influenced by many factors, including: plant phylogeny, soil biota, and the native or introduced status of soil-conditioning plants. We explore how phylogenetic relatedness influences the response of an herbaceous species, Aquilegia canadensis, to soil conditioning by heterospecifics. We include sterile soil controls to gain insight on the biotic drivers of plantsoil interactions (e.g. mutualists vs pathogens), and VC The Authors 2017.

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Discussion

Conclusion