Affiliations: Department of Environmental Engineering, School of
Environment and Resource Sciences, Zhejiang University, Hangzhou
310029, China | Institute of Geography and Environment, Jiangxi Normal
University, Nanchang 330027, China
Abstract: The ability of Elsholtzia splendens Naki (E. splendens) to
accumulate copper appears to be governed by its high degree of copper
tolerance. However, the tolerance mechanism on the physiological basis is
unknown. Using transmission electron microscope (TEM) and energy dispersive
analysis of X-rays (EDX), the likely location of copper within the cells of the
tolerant and non-tolerant was determined. Here the role of vacuolar and cell
wall compartmentalization in this copper tolerant plant were investigated. A
direct comparison of copper locations of E. splendens and the non-tolerant
Astragalus sinicus L. (A. sinicus) showed that the majority of copper in the
tolerant was localized primarily in the vacuolar, cell wall, on the
plasmamembrane, beside lipid grains induced by copper pollution, in the
chloroplasts and amyloids; but in the non-tolerant, copper precipitates only be
observed on the plasmamembrane, in the chloroplasts and cytoplasm under copper
exposure conditions that were toxic to both species. This revealed that the
tolerant accumulates more copper in the vacuole and cell wall than the
non-tolerant, where was regarded as the storage compartment of tolerant plant
or hyperaccumulator for heavy metals.
Keywords: A. sinicus, copper (Cu), E. splendens, localization, subcellular
