State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenhe District, Shenyang, People's Republic of China.
Ecotoxicology. 2013 Apr;22(3):476-85. doi: 10.1007/s10646-013-1041-5. Epub 2013 Jan 29.
A hydroponic experiment was carried out to investigate possible hormetic response induced by cadmium (Cd) in a potential hyperaccumulator-Lonicera japonica Thunb. The results showed that Cd at low concentrations induced a significant increase in plant growth, leaf water content and content of photosynthetic pigments in L. japonica, but decreased them at high concentrations, displayed inverted U-shaped dose response curves, confirming a typical biphasic hormetic response. The U-shaped dose response curves were displayed in malondialdehyde (MDA) and electrolyte leakage in leaves at low doses of Cd, indicating reduce oxidative stress and toxic effect. The increase of superoxide dismutase (SOD) and catalase (CAT) activities was observed along with the increased Cd concentration, indicative of increase in anti-oxidative capacity that ensures redox homeostasis is maintained. After 28 days exposure to 10 mg L(-1) Cd, stem and leaf Cd concentrations reached 502.96 ± 28.90 and 103.22 ± 5.62 mg kg(-1) DW, respectively and the plant had high bioaccumulation coefficient (BC) and translocation factor (TF'). Moreover, the maximum TF value was found at 2.5 mg L(-1) Cd treatment, implying that low Cd treatment improved the ability to transfer Cd from medium via roots to aerial structures. Taking together, L. japonica could be considered as a new plant to investigate the underlying mechanisms of hormesis and Cd tolerance. Our results suggest that hormetic effects should be taken into consideration in phytoremediation of Cd-contaminated soil.
进行了一项水培实验，以研究镉（Cd）在潜在超积累植物忍冬（Lonicera japonica Thunb.）中可能引起的激效反应。结果表明，低浓度 Cd 显著促进了忍冬的生长、叶片水分含量和光合色素含量，但在高浓度时则降低了它们，表现出倒 U 型剂量反应曲线，证实了典型的双相激效反应。叶片中丙二醛（MDA）和电解质渗漏在低剂量 Cd 下呈现 U 型剂量反应曲线，表明减轻了氧化应激和毒性作用。随着 Cd 浓度的增加，观察到超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性的增加，表明抗氧化能力增强，以确保氧化还原平衡得以维持。在暴露于 10 mg L(-1) Cd 28 天后，茎和叶中的 Cd 浓度分别达到 502.96 ± 28.90 和 103.22 ± 5.62 mg kg(-1) DW，且植物具有高生物富集系数（BC）和转移因子（TF'）。此外，在 2.5 mg L(-1) Cd 处理下发现了最大的 TF 值，表明低 Cd 处理提高了植物从根部将 Cd 转移到地上结构的能力。综上所述，忍冬可以被认为是一种新的植物，用于研究激效和 Cd 耐受的潜在机制。我们的结果表明，在 Cd 污染土壤的植物修复中应考虑激效作用。
