Salt glands enable salt but not metal(loid)s excretion in Limonium daveaui under amended saline and contaminated soils

Abstract Soil–plant interactions are essential for understanding adaptive responses to abiotic stressors such as salinity and metal(loid)s contamination. This study analyzed plant behavior of the recretohalophyte Limonium daveaui Erben when cultivated in saline and in gossan mine soils, both with and without organic–inorganic amendments. Analysis included soil physicochemical and biological parameters, multielemental composition of plant tissues, and the cationic profile of salts excreted by foliar salt glands. All plants grown in unamended gossan soil died, whereas amendment addition substantially improved both gossan and saline Fluvisol properties, raising pH in gossan soil, reducing salinity, increasing nutrient availability, generally stimulating microbial enzymatic activity, thereby allowing normal plant development. In amended gossan soil, plants accumulated high concentrations of As and Pb and moderate levels of other potentially hazardous elements (PHE) in roots and shoots without visible toxicity symptoms. Transfer coefficients revealed low PHE translocation but high biological absorption, indicating efficient uptake. Microscopic analyses showed the presence of the typical Limonium salt glands on both leaf surfaces through which plants excreted salts with macroelements but not As and Pb. The findings indicate that plant's primary tolerance strategy is based on accumulation of metal(loi)s in roots, rather than exclusion or excretion through foliar salt glands.