Histochemical localization of proteins by amido black and starch by potassium iodide-iodine in developing Scots pine seeds. (A) Megagametophyte cells with few protein storage vacuoles at the early embryogeny. (B) Megagametophyte cells stocked with protein storage vacuoles at the late embryogeny. (C) Megagametophyte cells with starch grains in the vicinity of the corrosion cavity at the early embryogeny. (D) Starch grains in the cotyledons and root meristem of a late embryo as well as in the megagametophyte. asr = arrow-shaped region, cc = corrosion cavity, e = embryo, esr = embryo surrounding region, m = megagametophyte. Bars: (A, C) 100 μm and (B, D) 200 μm.