Information on localization of Al and As in Tamarix gallica is required in order to better understand the detoxification mechanisms that confer tolerance in this halophyte plant species. Plants were subjected to different Al and As concentrations with and without salt supplementation. High concentrations of As and Al have been found in Tamarix gallica leaves and roots without symptoms of toxicity to the plant, which may be related to the particular compartmentation. A sequential extraction was carried out on leaves and roots to determine and compare the metal compartmentation in the plant. In this study, subcellular localization of As and Al was determined for the first time in roots and leaves of T. gallica, and provided evidence of the detoxification mechanisms of high As and Al concentrations. These results suggest that the subcellular distribution of As and Al play important roles in avoidance of metal toxicity. The most part of Al (that has high toxicity to the plant when available forms are present) was immobilized in cell walls, potentially suppressing its transportation to other subcellular compartments more susceptible to Al toxicity. On the other hand, the greater sequestration of As in the vacuole reduces its toxicity to the remaining cell organelles in the roots, but cell wall confinement remains an important tolerant mechanism in the leaves.

Plastic and microplastic debris (MP) constitute the most important pollutants of the solid litter with a high risk of sediment accumulation. Posidonia oceanica (L.) Delile is the main marine seagrass of the Mediterranean Sea which forms immense underwater meadows and deposits of seagrass beds covering the facades of sandy beaches. They are formed by roots and rhizome fragments gathered in fibrous marine balls, called aegagropiles (EGs), having the ability to trap several pollutants from the beaches and mainly microplastic. The present study aims at evaluating microplastic contamination in aegagropiles collected from four locations along the Tunisian coast in the southern Mediterranean basin (two northern sites (S1 and S2) and two southern-central sites (S3 and S4). Microscopic analysis revealed that red and blue microplastics dominated at all sites, with black fibers and fragments being the most prevalent forms and yellow (S3) and transparent particles in S1, S2, and S4. Polymer identification conducted using nuclear magnetic resonance (NMR) and Fourier-transform infrared spectroscopy (FTIR) detected microplastic types with contamination levels and microplastic accumulation variation among the four sites including polystyrene (PS) at sites S1, S3, and S4; ethyl vinyl acetate (EVA) at S1 and S3; polyethylene terephthalate (PET) at S1 and S2; and polyvinyl chloride (PVC) at S2 and S3. Our results highlight close relationships between anthropogenic activities, extensive plastic use, and elevated microplastic pollution in marine ecosystems, particularly in seagrass beds. These findings emphasize the importance of monitoring microplastic contamination to preserve the health of Mediterranean coastal environments.

Toxic compounds in the ecosphere are the consequence of environmental pollution, and have a disruptive influence in the environment. They affect...