Discovery of nanocrystalline botanical magnetite

Based on transmission electron microscopy and electron diffraction observat ions, we report the discovery of nanocrystalline botanical magnetite in iro n-rich extracts from disrupted grass cells. The majority of the magnetite n anocrystals extracted front the grass plants display cubo-octahedral shapes , with a minority of hexagonal prism morphologies. In addition to the const rained morphologies, each group has a narrow size distribution typical of i ntracellular-boundary organized biomineralization processes responsible for bacterial magnetite. The smallest cubo-octahedral botanical nanocrystals ( 4 +/- 1 nm) are an order of magnitude smaller than their bacterial counterp arts. These botanical nanocrystals are self-organized in ordered, micromete r-sized agglomerates, distinct from magnetite strings in magnetotactic bact eria and similar to some pedogenic magnetite currently attributed to inorga nic processes. We discuss the implications of our findings on the search fo r magnetite records of extraterrestrial and ancient terrestrial life, the o rigin of the terrestrial topsoil magnetite, and the potential for bioremedi ation using botanical magnetite.