关键词: 荒漠植物, 器官, 化学计量特征, 网络

Abstract: Abstract Aims The stoichiometriy of plant leaves, twigs, and fine roots are key indicators for characterizing whole-plant adaptive strategies and for revealing the mechanisms underlying plant-environment interactions. Investigating the interrelationships among leaf-twig-root stoichiometriy in desert plants, as well as their differences in environmental adaptability, is essential for advancing our understanding of plant resource allocation strategies. Methods In this study, we selected 20 desert plant species from the Baijitan region of Ningxia and measured the concentrations of carbon (C), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) in the leaves, twigs, and fine roots of 77 individuals. Important findings (1) Leaf C concentrations were significantly lower than those in twigs and fine roots, whereas the N, P, K, Ca, and Mg concentrations of twigs and fine roots were significantly lower than those of leaves. (2) Network analysis showed that the overall network parameters—edge density, average path length, diameter, average clustering coefficient, and modularity—were 0.40, 1.75, 4, 0.59, and 0.11, respectively; a total of 54 element-element pairs exhibited significant correlations. (3) Leaf K concentration and twigs C concentration exhibited the highest degree and closeness centrality, identifying them as hub elements within the network. Twigs showed the highest element degree, indicating that they function as the key hub organ. (4) Variance partitioning revealed that soil pH, total C, and total P had the strongest effects on the stoichiometry of leaves, twigs, and fine roots, respectively; soil total N had the greatest influence on leaf and twigs N concentrations, whereas soil pH most strongly affected fine-root C concentration. This study systematically uncovers the element coordination network among leaves, twigs, and roots of desert plants in the Baijitan region and elucidates their response mechanisms to soil environmental factors, providing new theoretical support for understanding desert plant ecological adaptation from a multi-element perspective. Our findings further highlight the need to incorporate key elements such as K, Ca, and Mg when examining plant stoichiometry, in order to more comprehensively reveal the coordinated regulation of C, N, P, K, Ca, and Mg across different organs and their roles in environmental adaptation.

Key words: desert plants, organs, stoichiometric characteristic, network