Sustainable phytoremediation of saline soils using Atriplex hortensis L.: a case study from Bizerte Lagoon, Northern Tunisia

Soil salinization is a growing global concern that undermines agricultural productivity and land sustainability. <i>Atriplex hortensis</i>, a C₃ annual halophyte, has shown promise as both a forage crop and a phytoremediation agent in saline environments. This field study assessed the potential of <i>A. hortensis</i> for reclaiming salt-affected soils in the Bizerte Lagoon region of Northern Tunisia. Plants were cultivated under naturally saline field conditions, and their physiological, morphological, and growth responses were monitored over six months. Results showed that increasing salinity significantly reduced biomass, with shoot dry mass decreasing from 168 g to 73.2 g, and root dry mass from 25.9 g to 15.6 g. Salinity stress significantly reduced chlorophyll fluorescence (ΦPSII) from 0.54 to 0.41 and stomatal conductance (gs) from 0.45 to 0.28 mol m^-2 s^-1, while relative water content (RWC) remained stable above 88%. Leaf area declined by 54%, limiting photosynthetic surface, whereas specific leaf area remained unchanged, indicating preserved leaf tissue density and structural integrity in <i>Atriplex hortensis</i>. A notable reduction in soil electrical conductivity from 3.48 to 2.26 dS m^-1 (-35%) was observed, indicating effective phytodesalination. Despite reduced biomass, <i>A. hortensis</i> maintained physiological stability and exhibited signs of salt tolerance. These findings support the use of <i>A. hortensis</i> as a dual-purpose species for forage production and soil desalination in arid and semi-arid ecosystems.