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Photomicrographs of tangential cryosections of 4-year-old and 40-year-old Norway spruce stems stained with safranin and Alcian Blue. Note the smaller cell size in the young stem (A) in comparison with the old stem (B). Developing xylem (blue) and mature xylem (red) are stained with Alcian Blue and safranin, for cellulosic and lignified cell walls, respectively. In B, only the developing xylem is shown. Tracheid (T), resin duct (RD), and rays (R) are indicated. Bars = 200 μm.
