水生植物自然会在遭受蓝藻水华的富营养化水体中与微囊藻毒素直接接触。在本研究中,调查了三种水下大型植物微藻藻(Ceratophyllum demersum L.),南香参(Vallisneria natans(Lour。)Hara和Myriophyllum spicatum L. )对微囊藻毒素-LR(MC-LR)的生物富集和解毒作用。我们的结果表明,C。demersum(3.85μgkg -1干重(DW)d -1)和sp。sp.atum(3.97μgkg -1 DW d -1)的平均每日摄取率均显着高于C. demersum(3.95μgkg -1 DW d -1)。V.natans(2.88微克kg -1DW d -1)。在C. demersum,V。natans和M. spicatum中MC-LR的平均每日生物转化率分别为1.95、2.16μgkg -1 DW d -1和3.97μgkg -1 DW d -1,分别降至0.75、0.64分别用丁硫氨酸亚砜亚胺(BSO,谷胱甘肽(GSH)生物合成的特异性和强效抑制剂)预处理后,分别为1.78μgkg -1 DW d -1和1.78μgkg -1 DW d -1。在C. demersum,V。natans和M. spicatum中,GSH含量显着下降了48.8%,65.7%和31.9%。在第8天,与对照组相比。此外,在整个生物积累期间,MC-LR刺激了所有三株植物的谷胱甘肽S-转移酶(GST)活性和谷胱甘肽还原酶(GR)活性。这些结果表明GSH参与了植物中MC-LR的解毒。此外,丙二醛(MDA)含量的结果表明,C。demersum中发生了细胞损伤,可以在解毒期恢复;而排毒系统可以保护藤蔓和角腐分枝杆菌免受5μgL -1 MC-LR的毒性。
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Bioaccumulation and detoxication of microcystin-LR in three submerged macrophytes: The important role of glutathione biosynthesis
Aquatic plants naturally come into direct contact with microcystins in eutrophic water bodies suffering from cyanobacteria blooms. In the present study, the bioaccumulation and detoxification of microcystin-LR (MC-LR) in three submerged macrophytes, Ceratophyllum demersum L., Vallisneria natans (Lour.) Hara and Myriophyllum spicatum L., were investigated. Our results showed that the average daily uptake rates of C. demersum (3.85 μg kg−1 dry weight (DW) d−1) and M. spicatum (3.97 μg kg−1 DW d−1) were both significantly higher than that of V. natans (2.88 μg kg−1 DW d−1). The average daily biotransformation rates of MC-LR in C. demersum, V. natans and M. spicatum were 1.95, 2.16 μg kg−1 DW d−1 and 3.97 μg kg−1 DW d−1, which deceased to 0.75, 0.64 and 1.78 μg kg−1 DW d−1, respectively, after pre-treatment with buthionine sulfoximine (BSO, a specific and potent inhibitor of glutathione (GSH) biosynthesis). GSH content significantly decreased by 48.8%, 65.7% and 31.9% in C. demersum, V. natans and M. spicatum on days 8, compared to the controls. In addition, glutathione S-transferase (GST) activity and glutathione reductase (GR) activity of all three plants were stimulated by MC-LR during the whole bioaccumulation period. These results indicated that GSH was involved in the detoxication of MC-LR in plants. Moreover, results of malondialdehyde (MDA) content indicated that cell damage occurred in C. demersum, which could recover in the detoxification period; whereas the detoxification system could protect V. natans and M. spicatum from the toxicity of 5 μg L−1 MC-LR.