Integrated Hydraulic and Biomechanical Strategies of Grapevine Fine Roots for Adaptation to Aridity and Salinity

Grapevines from the hyper-arid Atacama Desert possess unique hydraulic and biomechanical root adaptations that confer resilience to extreme drought and salinity. Here, we provide insights into root hydraulic properties, tissue–water relations, and mechanical traits to investigate resilience strategies in naturalized genotypes (R-65 and R-70) and commercial rootstocks (101-14Mgt and 110-R). Using root pressure probes, uniaxial tensile tests, pressure-volume analyses, and fluorescence microscopy, we evaluated the effects of salinity (0–250 mM NaCl) and severe drought on fine root functionality. The results reveal that the hyper-arid genotypes integrate superior hydraulic conductivity, elastic-plastic mechanical behavior, and reduced cortical damage to withstand high salinity and water stress. Although R-65 and R-70 maintained larger root diameters, higher water content, and stable osmolality under extreme salinity and drought conditions, commercial rootstocks showed increased stiffness, significant cortical lacunae formation, and reduced recovery capacity. These responses align with xerophytic adaptations that safeguard fine root functionality through enhanced energy dissipation, structural flexibility, and water retention, thereby minimizing permanent damage. Complementary hydraulic and biomechanical traits are critical for maintaining fine root integrity and stress resilience in hyperarid environments. This integrated analysis of hydraulic and mechanical traits highlights the potential of Atacama-adapted genotypes as genetic resources for breeding resilient crops. These findings contribute to the development of sustainable agricultural practices in saline- and drought-prone regions.