Plant Adaptation to Salinity: Physiological Pathways and Prospects for Crop Improvement—A Review

Soil salinity is a major abiotic constraint on crop growth, yield, and quality. Advancing salt-tolerant agriculture requires an integrated understanding of salinity-induced osmotic stress, ionic toxicity, and oxidative damage, and how physiological and molecular networks regulate these processes. This review synthesizes key responses to salt stress, including osmotic adjustment, ion transport and compartmentalization, photosynthetic acclimation, reactive oxygen species detoxification, and phytohormone-mediated regulation by integrating mechanistic trial-level and deployment-focused insights while providing a fundamental translational insight into durable crop salt tolerance. We further summarize transcriptional and post-transcriptional control mechanisms involving stress-responsive genes, transcription factor families, and microRNA/non-coding RNA regulation. Finally, we compare progress and constraints in conventional breeding, transgenic approaches, genome editing, and epigenetic strategies for improving salinity tolerance and highlight priorities for translating these mechanistic insights into durable field performance.