Liu D, Kottke I
Department of Biology, College of Chemistry and Life Sciences, Tianjin Normal University, Tianjin, PR China.
Cell Biol Toxicol. 2003 Oct;19(5):299-311. doi: 10.1023/b:cbto.0000004984.87619.15.
The ultrastructural investigation of the root cells of Allium cepa L. exposed to two different concentrations of chromium + nickel (Cr+Ni) (10 micromol/L and 100 micromol/L) revealed that toxic symptoms were induced by increasing heavy metal concentration and treatment time. Several significant ultrastructural changes were caused by 100 micromol/L Cr+Ni - deposition of electron dense material in cell walls; larger vacuolar precipitates surrounded by membranes inside vacuoles; increment of disintegrated organelles and high vacuolization in cytoplasm. The localization of the precipitates in which the metal ions were detected by electron energy loss spectroscopy (EELS) and electron spectroscopic imaging (ESI) was investigated. Chromium and nickel were localized in the electron dense precipitates of the root cells exposed to only 100 micromol/L Cr+Ni. None were found in the root cells exposed to 10 micromol/L Cr+Ni. Higher amounts of Cr+Ni were mainly accumulated in the cell walls and vacuoles of the fourth or fifth cortical layer.
对暴露于两种不同浓度铬 + 镍（Cr+Ni）（10微摩尔/升和100微摩尔/升）的洋葱根细胞进行超微结构研究发现，重金属浓度和处理时间增加会引发毒性症状。100微摩尔/升的Cr+Ni导致了一些显著的超微结构变化——细胞壁中电子致密物质的沉积；液泡内被膜包围的较大液泡沉淀物；细胞器解体增加以及细胞质中高度液泡化。研究了通过电子能量损失谱（EELS）和电子光谱成像（ESI）检测到金属离子的沉淀物的定位。铬和镍位于仅暴露于100微摩尔/升Cr+Ni的根细胞的电子致密沉淀物中。在暴露于10微摩尔/升Cr+Ni的根细胞中未发现。较高含量的Cr+Ni主要积累在第四或第五皮层的细胞壁和液泡中。
