Subcellular localization of cadmium in the root cells of Allium cepa by electron energy loss spectroscopy and cytochemistry

Journal of biosciences

Ingrid Kottke²  Donghua Liu1 2¹ 

[1] Department of Biology, College of Chemistry and Life Sciences, Tianjin Normal University, Tianjin 300074, People’s Republic of China$$;Eberhard-Karls Universität Tübingen, Botanisches Institut, Spezielle Botanik, Mykologie, Auf der Morgenstelle 1, D-72076 Tübingen, Germany$$

关键词: Allium cepa;    Cd;    cytochemistry;    electron energy loss spectroscopy;    root cells;   

DOI  :  

来源: Indian Academy of Sciences

【 摘 要 】

The ultrastructural investigation of the root cells of Allium cepa L. exposed to 1 mM and 10 mM cadmium (Cd) for 48 and 72 h was carried out. The results indicated that Cd induced several obvious ultrastructural changes such as increased vacuolation, condensed cytoplasm with increased density of the matrix, reduction of mitochondrial cristae, severe plasmolysis and highly condensed nuclear chromatin. Electron dense granules appeared between the cell wall and plasmalemma. In vacuoles, electron dense granules encircled by the membrane were aggregated and formed into larger precipitates, which increase in number and volume as a consequence of excessive Cd exposure. Data from electron energy loss spectroscopy (EELS) confirmed that these granules contained Cd and showed that significantly higher level of Cd in vacuoles existed in the vacuolar precipitates of meristematic or cortical parenchyma cells of the differentiating and mature roots treated with 1 mM and 10 mM Cd. High levels of Cd were also observed in the crowded electron dense granules of nucleoli. However, no Cd was found in cell walls or in cells of the vascular cylinder. A positive Gomori-Swift reaction showed that small metallic silver grains were abundantly localized in the vesicles, which were distributed in the cytoplasm along the cell wall.

【 授权许可】

Unknown