To investigate the effects of salinity stress on durum wheat cultivars at the critical stages of germination and seedling establishment under salinity stress, a study was conducted on eight durum wheat cultivars (Karim, Khiar, Inrat100, Maali, Monastir, Portodur, Razeg, and Salim) subjected to an increasing salinity concentration by using sodium chloride (NaC) (0, 2, 4, 6, and 10 g L⁻¹). Germination and seedling physiological parameters were measured and thoroughly analyzed. Salinity stress significantly decreased germination capacity (GC), germination rate (GR), final germination capacity (FGC), germination index (GI), mean daily germination (MDG), and velocity coefficient (Vc), whereas mean germination time (MGT) and the stress index (SI) increased. Plantlet growth and initial vigor (IV) were also significantly hampered. Regarding all these traits, the cultivars’ differences were revealed: Karim and Salim were the least affected, whereas Razeg and Maali were the most affected, and the other cultivars occupied an intermediate position. Depending on cultivar, salinity stress decreased the germination capacity and delayed its initiation. At low salinity stress (2–4 g L⁻¹ NaCl), the osmotic effect (OE) was the main cause of germination inhibition, whereas at high salinity stress (6–10 g L⁻¹ NaCl), the toxic effect (TE) dominated and irreversibly inhibited the germination process. The initial vigor and the stress index that clearly discriminate among the studied cultivars are useful traits for screening tolerant genotypes. Otherwise, durum wheat showed a higher plasticity with salinity at the germination stage, allowing it to develop better tolerance at this stage, as compared to early stage plantlet growth.

In this study, we evaluated the impact of brown seaweed extract (Ecklonia maxima) on the morphology and physiology of three different plant species. We conducted experiments using two types of fertilizers: an artificial fertilizer (0.1 g/L) and a biological extract of brown seaweed (Ecklonia maxima) at two concentrations (C1 at 1 mL/L and C2 at 2.5 mL/L). For melon, the application of C1 resulted in significant improvements in photosynthesis parameters, total chlorophyll content, and overall plant growth. When C2 was applied, it further enhanced these parameters, leading to a notable increase in shoot phytomass. In the case of cucumber, C1 led to increased resource allocation towards stems and leaves. Conversely, C2 increased the number of green leaves and contributed to higher shoot phytomass. For tomato plants, the application of C1 resulted in a slight increase in photosynthesis, but it did not significantly impact leaf growth. On the other hand, C2 induced a modest increase in photosynthesis, chlorophyll content, and root growth. In summary, our findings indicate that brown seaweed extract has a discernible influence on the physiology of the studied plants. However, the specific effects on resource allocation largely depend on the plant species and the concentration of the extract applied.

Exotic species have been widely used in reforestation in arid areas in northern Africa, as they provide ecosystem services that native species may be unable to supply. But information on their effect on ecosystem function and composition is scarce. We have evaluated the effect of 20-year-old Acacia saligna (Labill.) H.L. Wendl. plantations on the soil surface conditions and vascular plant composition in central Tunisia. Landscape function analysis (LFA) indices of soil stability, infiltration, and nutrient recycling underneath A. saligna increased by 1%, 138%, and 148%, respectively, in comparison to bare areas. This species, however, did not affect indicators of soil surface functionality, the spatial pattern of resource sinks-sources, or vascular plant species composition at a plot scale. This was probably due to low A. saligna cover, and a limited degree of litter incorporation into the soil surface. Our results suggest that the potential for improving ecosystem function and fostering succession by using this species seems to be limited in this arid environment.

In the saline depressions (Sebkhas) of Tunisia, Sulla carnosa expresses anarchic distribution, sometimes in association with halophytes sometimes individually. In order to explain this distribution, we investigated the effects of salinity on seed germination, the osmotic and toxic limiting factors, and the importance of some stimulating agents (priming agents) in the improvement of the tolerance to salinity at the germinating stage. A study was conducted on seeds harvested from the natural biotope Sebkha d'El Kelbia (35°50′34″N, 10°16′18″E), and an increasing concentration of NaCl (0, 5, 10, 15, and 20 g L⁻¹) was applied. Some priming agents were used to propose efficient, rapid, and low‐cost tools to improve the seed germination and tolerance of Sulla carnosa (Desf.) in saline depression. Salinity stress significantly decreased germination capacity and rate and delayed its initiation and maximum. Until 15‐g L⁻¹ NaCl, the most limiting factor of seed germination is the osmotic effect. At 20‐g L⁻¹ NaCl, the toxic effect dominates, and germination is irreversibly inhibited. Some priming agents have shown their efficiency in improving the germination capacity at 10‐g L⁻¹ NaCl and conferring a salt tolerance of up to 15‐g L⁻¹ NaCl.