关键词: 白刺, 化学计量特征, 演替阶段, 植物-土壤互作

Abstract: We analyzed the stoichiometry of carbon, nitrogen, and phosphorus in different organs of Nitraria tangutorum (roots, stems, and leaves) and soil across four succession stages in nebkhas in the desert-oasis ecotone: initial, developing, stable, and declining. The results showed that soil organic carbon, total nitrogen, total phosphorus, C:N, and C:P all peaked at the stable stage and then decreased, with reductions ranging from 25.9% to 64.9%, while the N:P was highest at the declining stage, increasing by 42.8% relative to the initial stage. Across all stages, leaf N and P contents were significantly higher than those in stems and roots. As succession progressed, stem and root C contents first increased and then decreased, peaking at the developing stage, with respective increases of 13.3% and 27.7%. Leaf and stem N contents were highest at the stable stage, with increases of 26.0% and 12.3%, respectively. Root N content declined by 40.7%. Stem and root P contents were lowest at the stable stage but rebounded significantly at the declining stage, increasing by 34.2% and 34.5%, respectively. The C:N and C:P of roots and stems initially increased and then decreased, peaking at either the developing or stable stages. In contrast, leaf C:N showed a gradual decline, leaf C:P first decreased and then increased, and leaf N:P gradually increased with succession. Multivariate analyses indicated that nebkha succession positively regulated soil physi-cochemical properties and root stoichiometric characteristics, while indirectly negatively regulating those of stems and leaves, thereby driving the plant-soil system away from nutrient accumulation toward depletion, and shifting nutrient limitation status from N limitation to N and P co-limitation.

Key words: Nitraria tangutorum, stoichiometric characteristics, successional stage, plant-soil interaction