Interspecific variability and morpho-physiological responses to salinity of Salix main Mediterranean species

Salinized soil productivity in arid and semi-arid regions is steadily decreasing and causing serious environmental and socioeconomic damages. Salix species known to grow under saline stress conditions could provide a viable solution for restoring degraded soil potential. Five Salix species (S. purpurea, S. alba, S. vitellina, S. babylonica, and S. viminalis) endemic to the southern Mediterranean region were grown in hydroponic conditions and assessed for their level of tolerance to salinity. Woody cuttings were treated for 30 days with either 0 or 100 mmol.L-1 NaCl. A high interspecific variability was highlighted during treatment as shown by changes in stomata size and density, growth, photosynthesis disruption, and electrolyte leakage. Based on a tolerance index, the five Salix species were ranked in decreasing order for their resistance to salinity: S. purpurea > S. alba > S. vitellina > S. babylonica >= S. viminalis. These results indicate that some tolerant Salix species could be used as an agroforestry model dedicated to restoration and valorization of soils degraded by salinization. [Journal translation]