Hepler P K
Eur J Cell Biol. 1981 Dec;26(1):102-11.
Postfixation of plant tissues with a mixture of osmium tetroxide and potassium ferricyanide (OsFeCN) yields a selective staining of the endoplasmic reticulum (ER) and nuclear envelope (NE). The other cytoplasmic organelles and inclusions are evident, but by comparison with the NE-ER they are weakly contrasted. Demarcation of the NE-ER results from the enhanced deposition of an electron-opaque reaction product on the inner leaflet of the membrane that extends into the cisternal space. The procedure thus renders the NE-ER readily apparent even when the elements are sectioned parallel to their surface and makes it possible to easily visualize their cellular pattern. Ultrastructural studies reveal with clarity tubular reticula and fenestrated lamellae that are extensively interconnected into one continuous membrane system. Problems with the OsFeCN procedure include the inability of the reagent to stain the NE-ER in all cells of a tissue, the occasional staining of non-ER such as dictyosomal cisternae and plastids, and the failure to selectively stain the NE-ER in protoplasts or single wall-less cells. Results obtained with OsFeCN are compared with other ER fixatives and stains including potassium permanganate and zinc iodide-osmium tetroxide. Despite its problems, under optimal circumstances OsFeCN is judged to be superior to other stain-fixatives for selectively contrasting the NE-ER compartment and is recommended generally for ultrastructural investigations.
用四氧化锇和铁氰化钾混合物（OsFeCN）对植物组织进行后固定，可对内质网（ER）和核膜（NE）进行选择性染色。其他细胞质细胞器和内含物清晰可见，但与核膜 - 内质网相比，它们的反差较弱。核膜 - 内质网的界限源于电子不透明反应产物在延伸至潴泡空间的膜内小叶上的增强沉积。因此，即使这些结构沿其表面进行切片，该方法也能使核膜 - 内质网易于显现，并能够轻松观察到它们的细胞模式。超微结构研究清楚地揭示了管状网络和有孔薄板，它们广泛相互连接形成一个连续的膜系统。OsFeCN方法存在的问题包括：该试剂无法对组织中的所有细胞的核膜 - 内质网进行染色；偶尔会对非内质网结构如高尔基体潴泡和质体进行染色；以及无法对原生质体或无细胞壁的单细胞中的核膜 - 内质网进行选择性染色。将OsFeCN得到的结果与其他内质网固定剂和染色剂（包括高锰酸钾和碘化锌 - 四氧化锇）进行了比较。尽管存在问题，但在最佳条件下，OsFeCN被认为在选择性区分核膜 - 内质网区室方面优于其他染色固定剂，一般推荐用于超微结构研究。
