Effect of Adaptation to High Concentrations of Cadmium on Soil Phytoremediation Potential of the Middle-European Ecotype of a Cosmopolitan Cadmium Hyperaccumulator Solanum nigrum L

Cosmopolitan character, and proven high and differentiated efficiency of Cd hyperaccumultor Solanum nigrum L. suggest possibility of optimizing its Cd phytoremediation capacity and applicability through searching among remote ecotypes/genotypes. However, the extensive studies on this hyperaccumulator have been limited to Far East (Asian) regions. Pioneer pot experiments on Middle European ecotype of S. nigrum with the use of concentration range 0-50 mg kg-1 Cd in soil, revealed its comparable to Asian ecotypes Cd phytoremediation capacity, but fundamentally different Cd tolerance threshold. It manifested itself in sharp biomass decline at Csoil ≈ 10 mg kg-1 Cd in Asian ecotypes versus gradual mild biomass decrease within the whole Csoil ≈ 0 -50 mg kg-1 Cd range with no crisis symptoms in Middle European ecotype. In its A50 variety adapted by using seeds originated from the first-generation plants grown in soil with Csoil ≈ 50 mg kg-1 Cd, cadmium tolerance, accumulation performance and all physiological parameters (chlorophyll, carotenoids, RuBisCO, and first- and second line defense antioxidant activity) were significantly enhanced while cell damage by ROS was considerably lesser. This makes Middle European ecotype and its adapted variety A50 particularly useful to sustainable decontamination of heavily polluted “hot spots” in the degraded post-industrial areas.