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

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.

越来越多的研究证据表明，植物-土壤互作（plant–soil interactions）对植物群落组成具有关键调控作用。然而，系统发育亲缘关系（phylogenetic relatedness）在调控植物与土壤生物群落（soil biota）互作过程中的作用仍未明晰，亟需更多案例研究以阐明系统发育是否以及如何影响植物-土壤互作，进而构建普适性的理论框架。本研究开展温室实验（glasshouse experiment），以检验加拿大耧斗菜（Aquilegia canadensis）与6种同期共存异种植物间的系统发育亲缘程度，是否通过土壤遗留效应（soil legacy effects）影响加拿大耧斗菜的生物量积累。同时，本研究还对比了加拿大耧斗菜在入侵种大蒜芥（Alliaria petiolata）驯化土壤与本土异种植物驯化土壤中的生长表现，并提出假说：大蒜芥的土壤驯化作用会抑制目标本土植物的生长表现。研究结果显示，加拿大耧斗菜在远缘异种植物驯化土壤中的生长表现显著优于近缘异种植物驯化土壤，且该效应在土壤灭菌处理后消失，这与近缘物种共享相似病原菌（pathogens）的理论预期相符。与我们的假说预期相反，入侵种大蒜芥驯化土壤与本土物种驯化土壤对加拿大耧斗菜的生长影响并无显著差异。加拿大耧斗菜在远缘而非近缘异种植物驯化土壤中表现更优的结果，符合系统发育约束的病原菌逃逸假说——该现象被认为可促进系统发育远缘物种的共存。不过，为了得到更可靠的物种共存预测结果，仍需开展成对植物-土壤反馈（plant–soil feedback）实验。