Ag particles in shoots of Brassica juncea (A, C), Festuca rubra (B) and Medicago sativa (D). Electron-dense Ag precipitates are found in association with different cell compartments. In (A), Ag precipitates appear as big electron-dense accumulations in the extracellular spaces among cortical parenchymal cells and as small spots on the cell walls (W) and on chloroplasts (Chl, arrows). In the parenchymal cells of vascular tissues, precipitates are found in the chloroplast stroma (B, Chl, arrows) and in the cytoplasm (Cyt), which often appears condensed (C and D, arrows). Organelles such as mitochondria, endoplasmic reticulum and vacuoles are not distinguishable. Note the big starch accumulations into the chloroplasts (B, Str). Bars correspond to 500 nm in (A, B, C) and 100 nm in (D).
Marchiol et al. Nanoscale Research Letters 2014 9:101 doi:10.1186/1556-276X-9-101