关键词: 旱生植物, 茎经济谱, 化学计量特征, 环境适应性

Abstract: Aims Potassium (K), calcium (Ca), and magnesium (Mg) are not only essential macronutrients required for plant growth and development, but also important physiological regulators of osmotic balance, structural stability, and metabolic activity, playing key roles in plant adaptation to drought environments. However, their roles in the trade-off between resource acquisition and conservation remain poorly understood, particularly in relation to the stem economic spectrum (SES). Methods In this study, we investigated 20 dominant plant species across eight sites in the Baijitan region of Lingwu, Ningxia, and analyzed the relationships between stem K, Ca, and Mg concentrations and key plant economic traits. Important findings (1) stem potassium concentration was significantly correlated with the primary axis of the stem economic spectrum, whereas calcium and magnesium concentrations showed no significant relationships with the spectrum; (2) coordinated variation among stem traits was significantly associated with soil nitrogen content, which was identified as the primary environmental driver; (3) with increasing soil nutrient availability, stem economic traits shifted toward an acquisitive strategy; and (4) stem potassium concentration decreased with increasing soil total carbon content. These findings indicate marked differences in the roles of K, Ca, and Mg in shaping stem economic strategies in xerophytic plants, with potassium being integrated into the construction of the stem economic spectrum, while calcium and magnesium may function through independent physiological regulatory mechanisms. In addition, soil nutrient status, particularly nitrogen availability, is a key environmental factor driving coordinated variation in stem traits. This study provides multi-element evidence linking mineral nutrient composition to stem economic strategies in arid plants, offering new insights into plant resource-use strategies and environmental adaptation.

Key words: xerophytic plants, stem economic spectrum, stoichiometric traits, environmental adaptability