Water potential in soil and Atriplex nummularia (phytoremediator halophyte) under drought and salt stresses.

Atriplex nummularia is a halophyte widely employed to recover saline soils and was used as a model to evaluate the water potentials in the soil-plant system under drought and salt stresses. Potted plants grown under 70 and 37% of field capacity irrigated with solutions of NaCl and of a mixture of NaCl, KCl, MgCl and CaCl reproducing six electrical conductivity (EC): 0, 5, 10, 20, 30, and 40 dS m. After 100 days, total water (Ψ) and osmotic (Ψ) potentials at predawn and midday and Ψ, matric potential (Ψ) and Ψ were determined. The type of ion in the irrigation water did not influence the soil potential, but was altered by EC. The soil Ψ component was the largest contributor to Ψ. Atriplex is surviving ECs close to 40 dS m due to the decrease in the Ψ. The plants reached a Ψ of approximately -8 MPa. The water potentials determined for different moisture levels, EC levels and salt types showed huge importance for the management of this species in semiarid regions and can be used to recover salt affected soils.