Aims

Functional traits play key role in plant resource-use strategy, but the intraspecific variation of root traits particularly of anatomy along large-scale environmental gradient has been poorly understood.

Methods

Here, we examined 16 morphological, anatomical, and chemical traits of leaves and absorptive roots (i.e., the first-order roots) for two wide-planted tree species, Ginkgo biloba and Eucommia ulmoides, sampled at five locations from subtropical, temperate, and cold-arid regions in China.

Results

Morphological traits in leaves tended to shift from conservative at resource-poor sites to acquisitive at resource-rich sites, showing lower leaf thickness and larger specific leaf area, while roots showed a reverse pattern. All anatomical traits in leaves and roots inclined to be more conservative in resource-poor sites. Leaves and roots generally showed negative relationships in analogous morphological traits, but positive in anatomical and chemical traits across both species. Intraspecific variation of leaf traits confirmed the existence of one-dimensional economics spectrum, whereas root traits displayed multidimensional variation, showing an independent dimension of cortex to stele size ratio.

Conclusions

Leaf and root traits in both species showed considerable intraspecific variations under changing environments, which improved whole-plant-level adaptions to climate and soil constraints, and exhibited different above- and belowground intraspecific economics spectra.