Assessing the potential of Arabidopsis halleri ssp. gemmifera as a new cadmium hyperaccumulator grown in hydroponics

Arabidopsis halleri ssp. gemmifera is a plant recently found in the heavy metal contaminated areas of Japan, and it contained a significant amount of Cd in its shoots. In this study, the potential of A. halleri ssp. gemmifera to accumulate Cd was investigated using hydroponics. The plants were grown for 21 d after Cd (control, 10, 100 and 400 µM) treatment. No reduction in shoot and root dry weight (DW) was observed when plants were grown in a nutrient solution containing up to 400 µM Cd. Cadmium concentrations in the plant parts increased significantly with Cd application rates, and reached a maximum of about 5641, 6643 and 15 967 µg g -1 in the leaves, stems and roots, respectively, at 400 µM Cd in the nutrient solution. Similarly, maximum Cd accumulation (dry weight × concentration) of 17.7 and 10.8 mg plant -1 in the shoots and roots, respectively, was obtained at 400 µM Cd. The ratio of shoot Cd/root Cd decreased with increasing rates of Cd supply from 1.8 at 10 µ M to 0.40 at 400 µM. Cadmium translocation from root to shoot ranged from 61 to 89% of the total Cd, showing a very high mobility of Cd in plants. The outcomes of this study and the field and greenhouse data previously reported confirm that this plant is a suitable candidate for the phytoremediation of Cd-contaminated soils. Furthermore, the concentration of Cd measured in the shoot indicates that A. halleri ssp. gemmifera could be considered a new potential Cd hyperaccumulator plant species. Key words: Cadmium, hyperaccumulator, hydroponics, phytoremediation, tolerance