纳米银颗粒对生菜吸收重金属镉的影响

采用水培试验方法, 对比研究纳米银颗粒及其溶出的银离子对生菜(Lactuca sativa)镉的吸收以及生理生化特性的影响。将生菜分别置于含或不含50 μg/L镉离子的0, 10, 100 和1000 μg/L纳米银悬浊液或0.1, 1和10 μg/L银离子溶液中暴露35天, 测定生菜叶子和根部的镉浓度、干重和鲜重、叶绿素含量及丙二醛(MDA)含量。结果表明, 纳米银只在1000 μg/L的最高浓度组引起生菜根部镉含量的显著上升(约 200%, p<0.001), 其他浓度下, 无论是生菜叶子或根部镉含量变化都不显著。纳米银和镉对生菜生物量和含水率没有显著影响, 生菜中的叶绿素和丙二醛含量也没有统计学上的显著变化, 纳米银的影响不能完全由溶出的银离子解释。由此可见, 在农业生产实际应用的浓度水平下, 纳米银没有引起镉在生菜中积累的显著增加, 在可食用部分镉含量有所减少, 纳米银的存在未带来额外的食品安全风险。

Effects of Silver Nanoparticles on the Accumulation of Cadmium by Lettuce (Lactuca sativa)

The effect of nanoparticle or ionic silver on cadmium accumulation by lettuce (Lactuca sativa) was investigated. The lettuce plants were grown in Hoagland solution amended with 0, 10, 100, 1000 μg/L nanoparticle silver or 0.1, 1, 10 μg/L ionic silver. Half of the lettuce were exposed to 50 μg/L ionic cadmium. After 35 days of exposure, wet weight, dry weight, cadmium, chlorophyll and malondialdehyde of leaves and roots of the lettuces were measured. Results show that except for the 1000 μg/L nanoparticle silver which increased cadmium concentration by about 200% (p<0.001) in lettuce roots, other concentrations of nanoparticle or ionic silver do not significantly change the cadmium concentration in either leaves or roots. Biomass, chlorophyll and malondialdehyde of the lettuces are not significantly changed either. Nanoparticle silver applied as agricultural fungicide in practical amounts will not lead to increased cadmium accumulation or detectable phytotoxicity symptoms in lettuce.