This review defined halophytes as plants able to complete their life cycle at high external salinities with high internal ion concentrations. High rates of ion uptake were judged important in osmotic adjustment. Evidence from metabolic studies together with direct measurements suggested a distinct compartmentation of ions within cells. Simple organic substances were surmised to act as compatible solutes in balancing cytoplasmic and vacuolar water potentials. [The SCI® indicates that this paper has been cited in more than 505 publications.