title: Towards a multidimensional root trait framework: a tree root review.
abstract: Contents 1159 I. 1159 II. 1161 III. 1164 IV. 1166 1167 References 1167 SUMMARY: The search for a root economics spectrum (RES) has been sparked by recent interest in trait-based plant ecology. By analogy with the one-dimensional leaf economics spectrum (LES), fine-root traits are hypothesised to match leaf traits which are coordinated along one axis from resource acquisitive to conservative traits. However, our literature review and meta-level analysis reveal no consistent evidence of an RES mirroring an LES. Instead the RES appears to be multidimensional. We discuss three fundamental differences contributing to the discrepancy between these spectra. First, root traits are simultaneously constrained by various environmental drivers not necessarily related to resource uptake. Second, above- and belowground traits cannot be considered analogues, because they function differently and might not be related to resource uptake in a similar manner. Third, mycorrhizal interactions may offset selection for an RES. Understanding and explaining the belowground mechanisms and trade-offs that drive variation in root traits, resource acquisition and plant performance across species, thus requires a fundamentally different approach than applied aboveground. We therefore call for studies that can functionally incorporate the root traits involved in resource uptake, the complex soil environment and the various soil resource uptake mechanisms - particularly the mycorrhizal pathway - in a multidimensional root trait framework.
authors.affiliation: Forest Ecology and Forest Management group, Wageningen University, 6700 AA, Wageningen, the Netherlands.|Plant Ecology and Nature Conservation group, Wageningen University, 6700 AA, Wageningen, the Netherlands.
authors.forename: Monique
authors.initials: M
authors.lastname: Weemstra
authors.affiliation: Plant Ecology and Nature Conservation group, Wageningen University, 6700 AA, Wageningen, the Netherlands.
authors.forename: Liesje
authors.initials: L
authors.lastname: Mommer
authors.affiliation: Department of Experimental Plant Ecology, Institute for Water and Wetland Research, Radboud University Nijmegen, 6500 GL, Nijmegen, the Netherlands.
authors.forename: Eric J W
authors.initials: EJ
authors.lastname: Visser
authors.affiliation: Plant Ecology and Nature Conservation group, Wageningen University, 6700 AA, Wageningen, the Netherlands.
authors.forename: Jasper
authors.initials: J
authors.lastname: van Ruijven
authors.affiliation: Department of Soil Quality, Wageningen University, 6700 AA, Wageningen, the Netherlands.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Kuyper
authors.affiliation: Forest Ecology and Forest Management group, Wageningen University, 6700 AA, Wageningen, the Netherlands.
authors.forename: Godefridus M J
authors.initials: GM
authors.lastname: Mohren
authors.affiliation: Forest Ecology and Forest Management group, Wageningen University, 6700 AA, Wageningen, the Netherlands.
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Sterck
mesh_terms: D038821:Mycorrhizae / Q000502:physiology; D018515:Plant Leaves / Q000502:physiology; D018517:Plant Roots / Q000502:physiology*; D019655:Quantitative Trait, Heritable; D014197:Trees / Q000502:physiology*
keywords: functional traits; mycorrhizal symbiosis; resource acquisition; root economics spectrum (RES); trait syndromes