Effects of Salt Stress on Growth, Proline and Mineral Content in Native Desert Species

Implementing large-scale restoration programs requires in-depth understanding about the salinity tolerance of native species, especially in the Arabian Peninsula where salinity is one of the most serious problems. Seedlings of four native species, namely Vachillea pachyceras, Haloxylon salicornicum, Rhanterium epapposum, and Farsetia aegyptia, were subjected to different salinity treatments (1.6 (control), 3, 5, 7, and 10 dS/m). Survival, growth performance, biomass and proline accumulation were assessed after six months of salinity exposure. Different mineral concentrations in the shoot and root tissues were assessed before and after the salinity exposure. Our results showed that salinity influenced the growth parameters, enhanced proline accumulation and changed the contents of essential elements. However, the effects of salinity stress on the growth and other parameters were largely species-specific. Proline accumulation increased with an increase in the salinity level in all the species. However, the mineral content in the root and shoot tissues showed variation, depending on the species and the level of salinity stress. Overall. H. salicornicum appeared to be the most tolerant species, as its seedling survival (100% at EC 10), and root and shoot biomass were impacted minimally; meanwhile, F. aegyptia (16.7% seedling survival at EC 10) appeared to be highly sensitive to the salinity. Data generated from this study will be helpful in screening the suitable species according to their salinity tolerance in salt-affected areas.