Elevational shifts in nutrient strategies of Abies fabri : From morphological foraging to enzymatic mining
L. Ji, Y. Hu, X. Lu, B. DuanAbstract
In alpine conifer forests, nutrient acquisition is shaped by nitrogen (N), phosphorus (P) and cold soils, but the elevational adjustment of nutrient‐acquisition traits in
Abies fabri
is still poorly known. Along the Gongga Mountain transect (2,800–3,400 m), soil inorganic N declined markedly with elevation, whereas available phosphorus, defined here as Bray‐1 extractable P, did not differ significantly among elevations.
Forests at 2,800, 3,100 and 3,400 m were sampled for soil nutrients, leaf N:P, foliar N and P fractions, root morphology, root exudation, mycorrhizal colonisation, root enzyme activities and non‐structural carbohydrates (NSC) to test how leaf nutrient status was linked to belowground acquisition traits. The trait pattern did not follow a directional available‐P gradient. With elevation, foliar N allocation shifted from Rubisco towards cell‐wall pools, while foliar P shifted towards metabolic and nucleic‐acid pools. Fine roots showed a more conservative morphology, with lower specific root length (SRL) and specific root area (SRA), whereas fine‐root acid phosphatase (APase) and N‐assimilating enzyme activities increased.
With the high‐elevation decline in leaf N:P,
A. fabri
responses reflected N–P stoichiometric context, internal nutrient allocation and root‐trait coordination rather than a simple soil‐P availability gradient.