Modulation of leaf economics spectrum, mycorrhizal type, and phylogeny on leaf nutrient resorption in a temperate...

Nutrient resorption is a key nutrient conservation strategy employed by plants. However, the leaf economics spectrum (LES), which reflects a fundamental trade-off between resource acquisition and conservation in plants, has not been properly linked to nutrient resorption. Mycorrhizal associations may influence nutrient resorption by affecting plant nutrient acquisition strategies, but their role in nutrient resorption remains poorly understood. Moreover, the role of phylogenetic signal in shaping nutrient resorption has been overlooked.

Here, we collected green and newly senesced leaves from 154 woody species spanning different leaf habits, growth forms, and mycorrhizal types in the China National Botanical Garden. Leaf morphological and chemical traits and nutrient resorption efficiency were determined. Phylogenetic effects on leaf nutrient resorption were analyzed. We investigated the influences of multiple biotic drivers on nitrogen resorption efficiency (NRE) and phosphorus resorption efficiency (PRE).

Differences in NRE and PRE were observed among plant functional types (PFTs). Importantly, NRE and PRE were closely associated with the LES, with conservative species tending to exhibit higher resorption efficiency than acquisitive species; ecto-mycorrhizae, evergreen, and tree species tended to adopt a more conservative strategy, whereas arbuscular mycorrhizae, deciduous, and shrub species exhibited a more acquisitive strategy. In addition, NRE and PRE showed phylogenetic conservatism; both showed distinct relationships with divergence time, which were mediated by mycorrhizal type, likely due to functional differences in soil P acquisition.

Nutrient resorption efficiency varies across PFTs with different LES strategies. We highlight how plant strategies, symbiotic associations, and evolutionary history shape leaf nutrient resorption. Our findings shed light on the mechanistic understanding of plant nutrient conservation strategies from ecological and evolutionary perspectives.