halophyte

A halophyte is a plant adapted to growing in soils or waters with high salinity. Halophytes can complete their life cycles in saline environments, tolerating NaCl concentrations that typical crops reject. They populate coastal salt marshes, mangroves, inland salt flats, and saline deserts, as well as coastal dunes and brackish wetlands. They are contrasted with glycophytes, which are salt-sensitive.

Adaptations to high salinity vary but include several broad strategies: exclusion of salt at the root to reduce uptake; sequestration of sodium and chloride ions in vacuoles or older tissues to keep cytosolic levels low; active salt secretion through specialized salt glands or bladders; production of compatible solutes such as proline and glycine betaine to maintain osmotic balance; and leaf or tissue succulence and anatomical changes that dilute ion concentrations. These strategies enable tolerance to high external NaCl and often allow rapid growth in saline habitats.

Examples of halophytes include Salicornia europaea (samphire or glasswort) and other Salicornia species, Spartina alterniflora (creeping cordgrass) in temperate marshes, Atriplex nummularia (old man saltbush) used as fodder in saline soils, Suaeda maritima (marsh saltwort), and Distichlis spicata (saltgrass).

Ecologically, halophytes form the vegetation of salt marshes, mangroves, and coastal prairies, contributing to shoreline stabilization and nutrient cycling. They are also of interest for saline agriculture, phytoremediation of saline or contaminated soils, and as potential food or forage resources in regions where soil salinity limits conventional crops.