Suaeda salsa: stress adaptation, soil restoration, and agronomic potential in salt-affected environments.

Abstract

Suaeda salsa is a widely distributed annual euhalophyte that thrives under both saline and saline-alkaline conditions, making it a valuable model for understanding plant salt-tolerance mechanisms and a promising resource for saline agriculture. However, the integrated understanding of how its physiological, biochemical, molecular, and microbial responses collectively support salt tolerance remains fragmented. Moreover, how these traits contribute to soil restoration and agricultural use remains insufficiently understood. S. salsa achieves optimal growth at 200 mM NaCl and tolerates salinity up to 400 mM NaCl through coordinated salt-tolerance responses. These responses comprise Na+ uptake and vacuolar sequestration, maintenance of K+/Na+ homeostasis, osmotic adjustment via compatible solutes, and strong antioxidant defenses. Moderate salinity enhances shoot biomass, chlorophyll content, electron transport rates, and carbon-assimilation enzyme activity, while high salinity triggers betacyanin accumulation that protects photosystems I and II integrity. Seed dimorphism and salinity-responsive reproductive development further support establishment in fluctuating saline habitats. Rhizosphere and endophytic microorganisms further enhance nutrient acquisition and salt tolerance, while field cultivation of S. salsa supports saline-soil reclamation and phytoremediation. Its genetic resources also highlight its potential for salt-tolerance breeding, establishing S. salsa as both a model halophyte and a practical resource for saline agriculture.