Abstract: Underground saline water can constrain agricultural and horticultural production through impairment of germination and early growth of seedlings. Effects of salinity were investigated in legume salt tolerant prosopis tamarugo at germination and early seeding stages. Seeds were treated during germination with either distilled water or one of six concentrations. The results showed that high salt concentrations (50%, 75% and 100% of underground saline water) had significant effects on germination percentage and seeding characteristics, while low concentrations (6.25% and 12.5%) tended to have promotive effect. The best results were obtained by using 25% of saline water. Quantitative variations in protein, carbohydrate, lipids, photosynthetic pigments and oxygen uptake were determined.