Alriplex halimus L. is an important forage plant in Mediterranean arid zones. The aim of this study is to identify, within the natural genetic diversity of a population, the types that can behave optimally under certain saline conditions. We focused our observations on the in vitro behavior of plants watered with a saline solution composed of NaCl +CaCl2 at 400 and 600 meq, and with 50% diluted and undiluted seawater. The morphological, physiological, biochemical and anatomical parameters involved in adaptation to salinity were examined, and the results showed that the plant's water status indicators were sensitive to variations in substrate salt content. In addition, the use of two types of substrate with increasing salt concentrations produced structural and biochemical variations in the plants tested. However, the behavior of these plants with regard to the origin of the salt is not always similar, and it would appear necessary to take this reaction into account in order to better understand the complexity of the mechanisms that enable the plant to adapt to the salt.