Leymus chinensis is one of the dominant species in the Eurasian steppe, and its rhizome clonal propagation capacity is a key determinant of population propagation. However, the mechanisms underlying rhizome proliferation and differentiation among different Leymus chinensis germplasms remain unclear. In this study, two germplasms exhibiting markedly distinct rhizome clonal propagation capacities (E, Lc19; P, Lc13) were selected as experimental materials. Using non-destructive approaches under common-garden conditions, and by integrating physiological measurements with metabolomic profiling, we elucidated the mechanisms driving the differentiation in their clonal growth strategies. The results revealed that germplasm E (Lc19) adopts a “belowground investment” strategy, characterized by an optimized “small-leaf, long-culm” configuration, high photosynthetic and water-use efficiency, and preferential allocation of resources to rhizome internodes. Its rhizome internodes and nodes displayed a metabolomic profile with pronounced “growth engine” features, in which key primary metabolites, including several amino acids involved in protein synthesis and carbon–nitrogen metabolism, lipid-related compounds associated with membrane construction, and representative secondary metabolites such as flavonoids and phenolic acid derivatives (e.g., flavones and hydroxycinnamic acid–related compounds), were significantly enriched, supporting cell proliferation, tissue elongation, and oxidative homeostasis, thereby facilitating rapid rhizome propagation. In contrast, germplasm P (Lc13) followed an “aboveground maintenance” strategy, whereby its larger leaf area and higher transpiration rate enhanced aboveground resource competition. Its rhizome internodes and nodes exhibited a metabolic network dominated by homeostasis maintenance, with significant enrichment of metabolites related to energy metabolism and stress protection, including carbohydrates involved in energy supply and transport, as well as antioxidative compounds associated with redox regulation, forming a “homeostasis-centered defensive structure” that prioritized functional stability. This study clarified the intrinsic mechanisms underlying the intraspecific differentiation of rhizome propagation capacity in Leymus chinensis from a physiological–metabolic perspective, uncovered the metabolic basis of different ecological adaptation strategies, and provided theoretical and practical implications for the differentiated utilization of germplasms with distinct proliferation strategies in grassland restoration, stability maintenance, and ecological management.
Zhang et al. (2026) studied this question.