Yu Xiao-Zhang, Gu Ji-Dong
Laboratory of Environmental Toxicology, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, SAR, People's Republic of China.
J Environ Monit. 2009 Jan;11(1):145-52. doi: 10.1039/b809304k. Epub 2008 Nov 12.
The remediation potential and metabolic responses of plants to ferricyanide were investigated using pre-rooted weeping willows (Salix babylonica L.) grown hydroponically in growth chambers and treated with potassium ferricyanide. Positive responses were observed for the plants exposed to </= 274.13 mg CN L(-1) as ferricyanide, exhibiting higher chlorophylls and soluble proteins compared with the controls. Visible toxic symptoms were only noted for the treatment exposed to 506.67 mg CN L(-1) after 120 h of incubation. Activity of superoxide dismutases (SOD) in leaves showed a slight change to ferricyanide exposure in most treatments. Catalase (CAT) and peroxidase (POD) activities were negatively correlated to the concentrations of ferricyanide. Of all the selected parameters measured, soluble proteins of plants were the most sensitive to ferricyanide, showing a significant linear correlation (R(2) = 0.952). Between 6.90 and 12.66% of the applied ferricyanide were removed by plants from the hydroponic solution at different treatments over the 192 h of exposure. Small amounts of the applied chemical taken up from the hydroponic solutions were detected in all parts of plant materials: the highest concentration was associated with roots in all treatments, followed by stems; the lowest was observed in leaves. The mass balance analysis showed that the total cyanide recovered in plant biomass was constant in all treatments, indicating that transport is a major limiting step for the uptake of ferricyanide by plants. The majority of the ferricyanide taken up from the growth media was possibly assimilated during transport through plants. The velocity of the removal processes can be described by Michaelis-Menten kinetics, and the half-saturation constant (K(M)) and the maximum removal capacity (v(max)) were estimated to be 228.1 mg CN L(-1) and 36.43 mg CN kg(-1) d(-1), respectively, using non-linear regression methods. These results suggest that weeping willows can take up, transport and assimilate ferricyanide; and phytoremediation is an option for cleaning up the environmental sites contaminated with cyanide complexes.
利用在生长箱中进行水培并经铁氰化钾处理的预生根垂柳（Salix babylonica L.），研究了植物对铁氰化物的修复潜力和代谢响应。对于暴露于≤274.13 mg CN L⁻¹（以铁氰化物计）的植物，观察到了积极响应，与对照相比，其叶绿素和可溶性蛋白含量更高。在孵育120小时后，仅在暴露于506.67 mg CN L⁻¹的处理中观察到明显的毒性症状。大多数处理中，叶片中超氧化物歧化酶（SOD）的活性对铁氰化物暴露的变化较小。过氧化氢酶（CAT）和过氧化物酶（POD）的活性与铁氰化物浓度呈负相关。在所有选定测量参数中，植物的可溶性蛋白对铁氰化物最敏感，呈现出显著的线性相关性（R² = 0.952）。在192小时的暴露期内，不同处理下植物从水培溶液中去除了6.90%至12.66%施加的铁氰化物。在植物材料的所有部位均检测到从水培溶液中吸收的少量施用化学品：所有处理中浓度最高的与根部相关，其次是茎部；叶片中含量最低。质量平衡分析表明，所有处理中植物生物量中回收的总氰化物是恒定的，这表明转运是植物吸收铁氰化物的主要限制步骤。从生长介质中吸收的大部分铁氰化物可能在通过植物的转运过程中被同化。去除过程的速度可用米氏动力学描述，使用非线性回归方法估计，半饱和常数（Kₘ）和最大去除能力（vₘₐₓ）分别为228.1 mg CN L⁻¹和36.43 mg CN kg⁻¹ d⁻¹。这些结果表明，垂柳可以吸收、转运和同化铁氰化物；植物修复是清理受氰化物络合物污染的环境场地的一种选择。
