Higher accumulation capacity of cadmium than zinc by Arabidopsis halleri ssp. germmifera in the field using different sowing strategies.

Aim: A-nine month of field trail was conducted to investigate the accumulation capacity of cadmium and zinc by Arabidopsis halleri spp. germmifera. Methods: An experimental site moderately contaminated with Zn and Cd was chosen to evaluate the field traits of seed sowing and seedling transplantation. The exchangeable fraction and total Cd and Zn in the soil and the concentration in harvested plants were determined by inductively coupled plasma mass spectrometer. Results: The shoot biomass of A. halleri ssp. germmifera increased after more than 8 months of cultivation, and it was approximately 2.13 t ha in the seedling transplantation group, which was more than three times higher than in the seed sowing group. The lower ratio of Zn/Cd concentration in plants than in the soil and the higher bioaccumulation factor indicated that A. halleri ssp. germmifera has a higher uptake efficiency for Cd than for Zn. In total, A. halleri ssp. germmifera removed 18.20 kg Cd ha and 27.38 kg Zn ha from the soil. After nine months of growth, A. halleri ssp. germmifera extracted (22.87 ± 9.21) % of total Cd concentration and (2.99 ± 0.94) % of total Zn concentration from the soil. However, no significant decrease of exchangeable concentration was shown in soil Cd and Zn, which revealed that the uptake of Cd and Zn by A. halleri ssp. germmifera not only came from exchangeable forms but also from non-exchangeable fractions. Conclusions: The results of present study indicated that A. halleri ssp. germmifera can be used to efficiently remove different forms of Cd from contaminated land. [ABSTRACT FROM AUTHOR]