Varied responses of Atriplex canescens to different intensities of drought, salinity and their coupled stresses

BACKGROUND AND AIMS: Drought and salinity are major abiotic factors limiting plant growth in arid regions and always co-occur. However, the response mechanisms of Atriplex canescens to drought and salinity, particularly their coupled stress, remain incompletely understood. To reveal the stress endurance thresholds and facilitate sustainable utilization in arid and saline lands, this research explores various responses of A. canescens to different intensities of drought, salinity and their coupled action. METHODS: A meta-analysis was performed based on research published between January 1970 and September 2025. In this research, we identified light, moderate and severe stress of drought with 60-80, 40-60 and 0-40 % of field water capacity (FWC) and electrical conductivity (EC) ≤ 8, 8-16 and >16 dS m-1 for salinity. KEY RESULTS: (1) The drought and salt tolerance thresholds of A. canescens are 0-40 % FWC and >16 dS m-1, respectively. (2) Atriplex canescens increases its root-to-shoot ratio to adapt to increased osmotic potential caused by severe drought and increases proline to cope with increased osmotic potential caused by severe salinity. (3) Coupled drought and salinity stress is more favourable for dry matter accumulation than their single stresses; however, it can intensify ionic toxicity and amplify oxidative stress. CONCLUSIONS: Irrigating A. canescens with an appropriate amount of brackish water can help improve and sustainably utilize salt-affected lands. Still, it is necessary to control ion toxicity and oxidative stress.