Figure 5 in The onset of hazel wood formation in Norway spruce (Picea abies [L.] Karst.) stems

<p>Distribution of polyphenolic compounds within disturbed zones. (a) Polyphenolic compounds present inside the longitudinal tracheids (black arrows), parenchyma rays (arrowheads), and both disturbed tracheids and traumatic parenchyma cells (yellow arrows). Unstained radial section, scale bar = 100 &mu;m. (b) Close-up view of disturbed cell lumens filled with polyphenolic compounds (arrows). Crystals were also present inside the traumatic parenchyma cells (arrowheads). Unstained radial section, scale bar = 50 &mu;m. (c) Polyphenolic compounds inside undisturbed tracheid lumens (black arrow). Yellow arrows show residues of disturbed tracheids. Bright-field microscopy of the cross-section made above a disturbed zone, scale bar = 50 &mu;m. (d) Polyphenolic compounds inside disturbed tracheids (black arrows) located in close proximity to a&nbsp;parenchyma ray. Yellow arrow shows a large disturbed tracheid which disrupts the entirety of a ray. There was a&nbsp;conspicuous hypertrophy and disordering of parenchyma cells in the upper part of a ray (yellow arrowheads). Radial section, scale bar = 100 &mu;m</p>