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

The Cs-133 and Sr-88 uptake by plant Raphanus sativus L was studied during cultivation in outdoor potted-soil. The distribution, accumulation of Cs-133, Sr-88 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 Sr-88 was far higher than that for Cs-133 when the concentration of Sr-88 was as the same as that of Cs-133 in the soil (The concentration of Sr-88 or Cs-133 in the soil was from 2.5 mg kg(-1) to 40 mg kg(-1)). The highest Sr-88 accumulation was 239.18 mu g g(-1) dw, otherwise, the highest Cs-133 accumulation was 151.74 mu g g(-1) dw (The concentration of Sr-88 in the soil was 40 mg kg(-1)), and the lowest Sr-88 accumulation was 131.03 mu g g(-1) dw, otherwise, the lowest Cs-133 accumulation was 12.85 mu g g(-1) dw (The concentration of Sr-88 in the soil is 5 mg kg(-1)). The Sr-88 and Cs-133 TF values were 1.16-1.72 and 0.24-0.60, respectively. There was little influence of high concentration of Sr-88 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 Sr-88 stress were that the MDA content was higher under the Sr-88 stress than that under the Cs-133 stress, and the activities of POD and CAT were lower under the Sr-88 stress than that under Cs-133 stress. (C) 2012 Elsevier Ltd. All rights reserved.