Variations in the traits of fine roots of different orders and their associations with leaf traits in 12 co-occuring plant species in a semiarid inland dune

Aim Variations in plant traits are closely linked to the functional trade-off between resource acquisition and conservation. However, there has been little research on interspecific variations in the traits of fine roots with different orders and their associations with leaf traits in semiarid inland dunes. Methods We examined the first four root orders and leaves of 12 species (seven herbs and five shrubs), representing a broad range of taxa, co-occurring in a semiarid inland dune and evaluated their root biomass ratio and nine key morphological and chemical traits. Results We observed substantial variations in root traits among species and among root orders within species. The root economics spectrum (RES) spanned across the first three orders, representing a resource acquisition and conservation strategy in which specific root length, specific root area and root N concentration decreased and root diameter increased with root order. Most of the fine root and leaf traits were primarily loaded on the first and second axes of the principal component analysis. Herbs and shrubs presented resource acquisitive and conservative strategies, respectively, due to their contrasting leaf and fine root traits. Phylogenetic conservatism was stronger in roots than in leaves. Conclusions The leading RES in the fine roots of different orders existed in the semiarid inland dune, emphasizing the importance of interspecific and intraspecific variations in the traits of fine roots of different orders in understanding root structure, function and their coordination. Partial trait integration across leaves and fine roots implies limited support to the plant economics spectrum.