The effect of arsenic and heavy metals on growth and metal accumulation by artichoke (Cynara scolymus L.) and savory (Satureja hortensis L.)

The present investigation assessed the effects of a metalloid (arsenic) and two heavy metals (cadmium and mercury), on the growth and metal accumulation in two medicinal plant species, artichoke (Cynara scolymus L.) and Savory (Satureja hortensis L.). The experiment was conducted hydroponically in spiked solution with different concentrations of arsenic (0, 20, 100, and 500 μM), cadmium (0, 10, 50, 250, and 500 μM) and mercury (0, 5, 25, and 50 μM) for four weeks. Under elevated arsenic and heavy metal stresses, root and shoot biomass of artichoke and savory were reduced. Shoot dry weight was significantly (p<0.05) decreased at arsenic supply levels of 20-500 μM, cadmium levels of 10-500 μM and mercury levels of 5-50 μM compared to the control plants. Similar response patterns to arsenic, cadmium and mercury supply levels were noted for root dry weight in the two plant species. Arsenic and heavy metal accumulated by the plants root and shoot linearly increased with increasing their supply levels. More accumulation of arsenic, cadmium and mercury was observed in roots than shoots in artichoke and savory. Artichoke had higher metalloid and heavy metal uptake, bioaccumulation factor, and root-to-shoot translocation efficiencies than those of savory. This can be attributed to a greater accumulating capacity in artichoke. Overall results indicated that metal phytoextraction using the artichoke can be applied to clean up soils moderately contaminated by arsenic, cadmium and mercury in polluted lands.