235 seedlings of Avicerniannritwwere grown for 12 months in nurient solutions containing 0, 25, 50, 75, 100, 125 and 15070 artificial s€awater. The salt concentation in the various organs and salt excretion from the leaves were measured to examine the salt regulation in the seedlings. The wabr potential of vuious organs in relation 3o extemal media was measured concurrently wittr salt concentration in the seedlings to discuss ttre wuer potential adjustment. A . marhw was found to absorb a great

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... amount of sodium (Na) and chloride (Cl-). The salt uptake increased wittr the increase of extemal salinity and reached no ttre ceiling level at around the normal extemal seawater. The salt concenEations in the seedlings were maintained at levels higher than those of extemal media. This contributed to produce water potential in the seedlings lower than that of extemal media. The salt excretion was found to be related positively with the salt concenration in leaves. It was concluded that A. marina seedlings equip'ped a workable mechanism of salinity regulation through absorption and excretion. And therefore it can survive in the high salinity environment.