Accumulation and effects of uranium on aquatic macrophyte Nymphaea tetragona Georgi: Potential application to phytoremediation and environmental monitoring
2019
Li, Chen | Wang, Maolin | Luo, Xuegang | Liang, Lili | Han, Xu | Lin, Xiaoyan
This study analyzed the ability of Nymphaea tetragona Georgi (N. tetragona) to accumulate water-borne uranium and any effects this could exert on this plant species. In accumulation experiments, N. tetragona was exposed (21 d) to different concentrations of uranium (0–55 mg L−1) and the content of uranium was determined in water and plant tissues (leaves, submerged position and plant) to determine the translocation factor (TF) and bioconcentration factor (BCF). The content of uranium in the plant and plant tissues showed concentration-dependent uptake, leaves were the predominant tissue for uranium accumulation, and TF and BCF values were both affected by the concentration of uranium in the water. In this research, the uranium content and BCF value in the leaves of N. tetragona were upto 3446 ± 155 mg kg−1 and 73 ± 3, respectively. In physiological experiments, uranium treatment boosted the activity of peroxidase (POD), superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) in the leaves, and increasing uranium concentrations aggravated damage to the cell membrane system. Uranium contamination significantly inhibited the content of soluble protein, as well as chlorophyll-a, chlorophyll-b and carotene in the leaves, indicating the structure and function of chloroplast were destroyed, reducing the photosynthetic performance of plants. These results indicate that the macrophyte N. tetragona can accumulate uranium while showing a stress response via metabolic mechanisms under uranium exposure, and it may be a suitable bioremediation candidate for aquatic marine contamination.
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