Gymnosperms demonstrate patterns of fine‐root trait coordination consistent with the global root economics space

1. Gymnosperms encompass a diverse group of mostly woody plants with high eco-logical and economic value, yet little is known about the scope and organiza-tion of fine-root trait diversity among gymnosperms due to the undersamplingof most gymnosperm families and the dominance of angiosperm groups in recentsyntheses.
2. New and existing data were compiled for morphological traits (root diameter,length, tissue density, specific root length [SRL] and specific root area [SRA]), thearchitectural trait branching ratio, root nitrogen content [N] and mycorrhizal colo-nization. We used phylogenetic least squares regression and principal componentanalysis to determine trait–trait relationships and coordination across 66 species,representing 11 of the 12 extant gymnosperm families from boreal, temperate,subtropical and tropical biomes. Finally, we compared the relationship betweenfamily divergence time and mean trait values to determine whether evolutionaryhistory structured variation in fine-root traits within the gymnosperm phylogeny.
3. Wide variation in gymnosperm root traits could be largely captured by two pri-mary axes of variation defined by SRL and diameter, and root tissue density androot nitrogen, respectively. However, individual root length and SRA each hadsignificant correlations with traits defining both main axes of variation. Neithermycorrhizal colonization nor root branching ratio were closely related to othertraits. We did not observe a directional evolution of mean trait values from olderto more recently diverged gymnosperm families.
4. Synthesis. Despite their unique evolutionary history, gymnosperms display a rooteconomic space similar to that identified in angiosperms, likely reflecting com-mon constraints on plants adapting to diverse environments in both groups. These findings provide greater confidence that patterns observed in broadsyntheses justly capture patterns of trait diversity among multiple, distinct lin-eages. Additionally, independence between root architecture and other traitsmay support greater diversity in below-ground resource acquisition strategies.Unlike angiosperms, there were no clear trends towards increasingly thin rootsover evolutionary time, possibly because of lower diversification rates or uniquebiogeographic history among gymnosperms, though additional observations areneeded to more richly test evolutionary trends among gymnosperms.