Cellular biogenesis of metal nanoparticles by water velvet (Azolla pinnata): Different fates of the uptake Fe3+ and Ni2+ to transform into nanoparticles

TEM images of iron nanoparticles in root cells of Azolla pinnata.满江红（Azolla pinnata）根细胞内铁纳米颗粒的透射电子显微镜（Transmission Electron Microscopy, TEM）图像