Physiological Responses of Plants to Water and Salinity Stress

Plants exposed to water deficit or elevated salinity undergo a suite of integrated physiological adjustments to survive and sustain growth. The initial response often involves rapid stomatal closure to reduce transpirational water loss, mediated by abscisic acid accumulation and changes in guard-cell osmotic potential. Concurrently, roots may alter growth patterns to explore deeper or moister soil layers, while aquaporin channels adjust to regulate cellular water flux. Osmotic adjustment through accumulation of compatible solutes—such as proline, glycine betaine and soluble sugars—helps maintain cell turgor and enzyme function. At the cellular level, ion homeostasis systems, including selective exclusion of sodium and retention of potassium, preserve membrane integrity and photosynthetic efficiency. Reactive oxygen species generated under stress are scavenged by antioxidant enzymes (superoxide dismutase, catalase and peroxidases) and non-enzymatic metabolites to prevent oxidative damage. Long-term acclimation may involve epigenetic modifications and stress-responsive gene expression, establishing a ‘stress memory’ that enhances resilience upon recurrent exposure. Understanding these mechanisms underpins efforts to breed or engineer crops with improved tolerance and informs agronomic practices aimed at mitigating the impacts of drought and soil salinisation on global food security.

Research from Nature Portfolio

Recent studies have applied multidisciplinary approaches combining physiological measurements, epigenetic profiling and gene expression analyses to elucidate salt-tolerance mechanisms in olive cultivars. Under controlled salinity treatments, tolerant varieties exhibited higher photosynthetic rates, improved water use efficiency and selective ion partitioning, accompanied by specific DNA methylation changes and expression shifts in aquaporin, photosystem and retrotransposon-associated genes. These findings highlight coordinated regulation at the physiological, epigenetic and transcriptional levels, and identify candidate markers for breeding programmes aimed at enhancing salt resilience in perennial crops.

Physiological Responses of Plants to Water and Salinity Stress publication trend

The graph below shows the total number of articles in physiological responses of plants to water and salinity stress across all publications each year (not limited to Nature Index journals).

Technical terms

Stomatal conductance: Rate at which CO₂ enters and water vapour exits leaves through stomata, reflecting gas-exchange efficiency.

Osmotic adjustment: Accumulation of compatible solutes within cells to maintain turgor under water deficit or high salinity.

Reactive oxygen species: Highly reactive molecules (e.g. superoxide, hydrogen peroxide) produced under stress and detoxified by antioxidant systems.

Epigenetic modification: Heritable changes in gene function, such as DNA methylation, that occur without alteration of the DNA sequence and can affect stress memory.

Aquaporin: Membrane-embedded protein that facilitates selective water transport across cell membranes, playing a key role in cellular water balance.

References

1. Drought and Salinity Stress Responses and Microbe-Induced Tolerance in Plants. Frontiers in Plant Science (2020).
2. Physiological, epigenetic and genetic regulation in some olive cultivars under salt stress. Scientific Reports (2019).
3. Behavior of Four Olive Cultivars During Salt Stress. Frontiers in Plant Science (2019).
4. Phenotypic, Metabolic and Genetic Adaptations of the Ficus Species to Abiotic Stress Response: A Comprehensive Review. International Journal of Molecular Sciences (2024).