# Salt stress responses and tolerance mechanisms in native desert plants of the UAE: growth, biochemical, and antioxidant perspectives

## TL;DR

This study examines how four native UAE desert plants respond to high soil salinity, identifying which species are most resilient and the mechanisms they use to survive.

## Contribution

The study provides field-based insights into salinity tolerance mechanisms of native UAE desert shrubs under realistic conditions.

## Key findings

- Salvadora persica and Lycium shawii showed the highest salinity tolerance with strong osmotic adjustment and antioxidant activity.
- Calligonum comosum had limited high-salinity tolerance, with reduced survival and photosynthetic performance.
- Ion regulation and oxidative protection were key factors in salinity tolerance across species.

## Abstract

Soil salinization threatens productivity and ecosystem stability in arid regions, yet salinity-tolerance mechanisms of native UAE desert shrubs remain poorly resolved under field-like conditions. This study aimed to identify tolerance strategies and rank salinity resilience among Lycium shawii, Salvadora persica, Calligonum comosum, and Haloxylon salicornicum. Plants were grown in an outdoor pot trial under ambient desert conditions and irrigated with three salinity levels (ECw = 1.5, 10, and 25 dS m-¹). Severe salinity (25 dS m-¹) revealed clear interspecific divergence: S. persica and L. shawii maintained 100% survival, relatively stable water status and photosynthetic performance, and reduced membrane injury and lipid peroxidation. Their tolerance was associated with stronger osmotic adjustment (higher proline and soluble sugars), improved ion homeostasis (lower shoot Na+ accumulation and more stable K+ status relative to H. salicornicum), and enhanced antioxidant capacity (higher enzyme activities and radical scavenging). In contrast, C. comosum showed reduced survival (83.3%), marked dehydration, strong photosynthetic inhibition, weak antioxidant activation, and pronounced membrane damage, indicating limited high-salinity tolerance. H. salicornicum displayed intermediate performance, consistent with ion-handling–based tolerance but with higher physiological costs. Overall tolerance ranked S. persica > L. shawii > H. salicornicum > C. comosum. Correlation analysis and PCA supported coordinated contributions of water status, ion regulation, and oxidative protection to tolerance. These findings provide field-relevant mechanistic evidence to guide species selection for biosaline agriculture and saline-land rehabilitation in arid environments.