Partial coordination of leaf water relations with the leaf economics spectrum across diverse forest types

Understanding how leaf water relations integrate with carbon economy is central to plant physiological ecology and to predictions of vegetation responses to environmental change, yet the degree of their coordination remains debated. We investigated relationships between leaf pressure-volume (PV) traits (leaf-specific capacitance at full turgor per dry mass (C*ft,mass), osmotic potential at the turgor loss point (πtlp), and other PV traits) and leaf economics spectrum (LES) traits (leaf nitrogen content, specific leaf area, and photosynthetic capacity) across temperate, subtropical, and tropical forests. These 2 suites of traits exhibited statistically partial coordination: C*ft,mass was tightly coupled with LES traits, whereas πtlp was independent of the LES framework, and this partial coupling was primarily driven by leaf saturated water content. Notably, coordination was strongest at the subtropical site, where conservative strategies strengthened the integration between PV and LES traits, thereby improving resource-use efficiency. This partial coupling provides insights into the multidimensional nature of plant functional strategies and the mechanisms underpinning species coexistence across forest types.