2.10 Histological Analysis
For transmission electron microscopy, cassava leaves were fixed in 2.5% glutaraldehyde then transferred to osmium tetraoxide. The fixed samples were dehydrated in an ethanol gradient then transferred to propylene oxide solution, after which they were slowly polymerized in acrylic resin (London Resin Company) for at least 48 h. Thin sections (70 nm) were obtained using a diamond knife microtome (Ultracut E; Reichert Technologies). The sections were placed on 100-mesh copper grids, stained with uranyl acetate for 30 mins, and then stained with lead citrate for 15 mins. The sections were observed using a Hitachi HT7700 transmission electron microscope (Japan).