Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brasil.
Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brasil.
Ecotoxicology. 2020 Mar;29(2):196-202. doi: 10.1007/s10646-019-02152-9. Epub 2020 Jan 26.
In order to evaluate the differential absorption and toxicity of arsenate (As) and arsenite (As), Lemna valdiviana plants were grown in a nutrient solution and subjected to 0.0 (control); 0.5; 1.0; 1.5; 2.0; 3.0; 4.0; 5.0 and 7.5 mg L of As or As for three days. Exposure to both chemical forms resulted in As bioaccumulation, although As-grown plants showed higher As content in tissues. In As-grown plants, the relative growth rate (RGR) decreased to 50%, at a concentration of 4.0 mg L, while for treatments with As, the same decrease was observed at 1.0 mg L. The tolerance index decreased with increasing concentrations, with lower values for As. Plants treated with As showed increased superoxide anion levels, whilst higher levels of hydrogen peroxide were present in AsV-treated plants. Moreover, malondialdehyde (MDA) levels were higher for plants subjected to As when compared to As at lower concentrations. Concentrations of 1 mg L of As and 4 mg L of As showed equivalent MDA levels. Superoxide dismutase and catalase activities were increased at low concentrations and were inhibited at higher concentrations of As and As, whereas peroxidase activity was positively modulated by increased As or As concentrations. In conclusion, L. valdiviana plants took up and accumulated arsenic as As or As, demonstrating the potential for phytoremediation of this metalloid. Furthermore, As-exposed plants showed enhanced toxicity when compared to As, at the same applied concentration, although toxicity was more related to internal As concentrations, regardless of the chemical form applied.
为了评估砷酸盐（As）和亚砷酸盐（As）的差异吸收和毒性，浮萍（Lemna valdiviana）植物在营养液中生长，并暴露于 0.0（对照）；0.5；1.0；1.5；2.0；3.0；4.0；5.0 和 7.5 mg/L 的 As 或 As 中 3 天。尽管 As 生长的植物在组织中显示出更高的 As 含量，但这两种化学形式的暴露均导致了 As 的生物积累。在 As 生长的植物中，相对生长率（RGR）下降到 50%，在 4.0 mg/L 的浓度下，而对于 As 处理，在 1.0 mg/L 时观察到相同的下降。随着浓度的增加，耐量指数降低，As 的值较低。用 As 处理的植物表现出超氧阴离子水平升高，而在用 AsV 处理的植物中存在更高水平的过氧化氢。此外，与较低浓度的 As 相比，用 As 处理的植物中丙二醛（MDA）的水平更高。当浓度为 1 mg/L 的 As 和 4 mg/L 的 As 时，MDA 水平相当。低浓度下，超氧化物歧化酶和过氧化氢酶活性增加，而在较高浓度的 As 和 As 下被抑制，而过氧化物酶活性则被增加的 As 或 As 浓度正向调节。总之，浮萍植物吸收并积累砷，无论是 As 还是 As，这表明该类金属元素具有植物修复的潜力。此外，与相同浓度的 As 相比，暴露于 As 的植物表现出更高的毒性，尽管毒性更与内部 As 浓度有关，而与所应用的化学形式无关。
