Early and late developmental stages of Scots pine embryogenesis. (A) The dominant embryo and subordinate embryos in the corrosion cavity at the early embryogeny surrounded by the embryo surrounding region (esr) of the megagametophyte highlighted with red color. The arrow-shaped region (asr) of the megagametophyte outside the esr highlighted with blue color. (B) The dominant embryo in the corrosion cavity at the late embryogeny. The esr of the megagametophyte highlighted with red color and asr highlighted with blue color. asr = arrow-shaped region, cc = corrosion cavity, e = embryo, esr = embryo surrounding region, m = megagametophyte, mm = megaspore membranes, nc = nucellar cap, nl = nucellar layers, nt = cellular nucellus, sr = suspensor remnants. Bars: 100 μm.