Elasticity Range Addresses Global Patterns of Plant Drought Resistance.

Abstract

Elastic adjustment enables turgor maintenance under drought, yet its potential as a reliable predictor of species-level drought resistance remains controversial due to the static nature of traditional metrics. This study investigates the variation in cell wall elastic properties across a global dataset, introducing the "Elasticity Safety Range"-defined as [Ln (ε_max/ε_mean)]-as a dynamic functional indicator, where ε_max and ε_mean represent the maximum and mean elastic modulus, respectively. Unlike the ε_max, this index captures the capacity for reversible elastic modulation required to maintain turgor under stress. We found that the Elasticity Safety Range was more strongly correlated with climate aridity than traditional ε_max and ε_mean, revealing a fundamental divergence in survival strategies. Specifically, evergreen species exhibited a widened safety range under aridity, reflecting a "Persistence Strategy" to protect expensive foliage through active cell wall softening. In contrast, deciduous species showed a diminished or negligible range in arid conditions, consistent with a "Phenological Avoidance" strategy (leaf shedding). Our findings demonstrate that the Elasticity Safety Range offers novel insights into the trade-off between structural investment and physiological regulation, providing a robust tool for assessing plant vulnerability to climate intensification.