The uptake of Cs and Sr from soil to radish (Raphanus sativus L.)- potential for phytoextraction and remediation of contaminated soils

The 133Cs and 88Sr uptake by plant Raphanus sativus L. was studied during cultivation in outdoor potted-soil. The distribution, accumulation of 133Cs, 88Sr and the antioxidant responses in plants were measured after 30 and 60 days of cultivation. The results showed that the uptake capacity of radish for 88Sr was far higher than that for 133Cs when the concentration of 88Sr was as the same as that of 133Cs in the soil (The concentration of 88Sr or 133Cs in the soil was from 2.5 mg kg−1 to 40 mg kg−1). The highest 88Sr accumulation was 239.18 μg g−1 dw, otherwise, the highest 133Cs accumulation was 151.74 μg g−1 dw (The concentration of 88Sr in the soil was 40 mg kg−1), and the lowest 88Sr accumulation was 131.03 μg g−1 dw, otherwise, the lowest 133Cs accumulation was 12.85 μg g−1 dw (The concentration of 88Sr in the soil is 5 mg kg−1). The 88Sr and 133Cs TF values were 1.16–1.72 and 0.24–0.60, respectively. There was little influence of high concentration of 88Sr on the total biomass of plants, so the radish is one of the ideal phytoremediation plant for Sr polluted soils. The important physiological reasons that radish had good tolerance to 88Sr stress were that the MDA content was higher under the 88Sr stress than that under the 133Cs stress, and the activities of POD and CAT were lower under the 88Sr stress than that under 133Cs stress.

► Radish is a kind of native plant with high biomass and fast growth. Its uptake capacity of radish for 88Sr was far higher than that for 133Cs when the concentration of 88Sr was the same as that of 133Cs in the soil.
► The TF values of radish for 88Sr were 1.16–1.72.
► Radish is one of the ideal phytoremediation plant for Sr polluted soils.
► The important physiological reasons that radish had good tolerance toward 88Sr stress were that the MDA content was higher under the 88Sr stress than under the 133Cs stress, and the activities of POD and CAT were lower under the 88Sr stress than under 133Cs stress.