Fig. 3.

IAA immunolocalization in the stem bases of rejuvenated and mature soft shoots. a–f Transverse sections of rejuvenated soft shoots in walnut. a, b IAA is located in the stem 1–3 days after induction, but only in sieve cells and companion cells. c By 4 days, as the cambium thickens, IAA concentrates in this tissue. d By day 5, some meristem cells have divided and IAA is distributed in the meristems and ray cells. e IAA is present less in the initial cells of root primordia, part of cambium and S&Cs by 7 days. f The root primordia form by 9 days. IAA is distributed in the primordia, particularly in the tip regions. g–i IAA in the basal regions of mature soft shoots after 1 day (g), 5 days (h), and 9 days (i) of rooting induction. IAA signal is low at those times. The arrows indicate IAA signals. Arrowheads indicate the tissue structure. ca cambium, co cortex, m meristem, ph phloem, r ray cell, rp root primordia, rpic root primordia initial cells, S&Cs sieve and companion cells, sr sclerenchyma, xy xylem. Scale bars: 200 μm (e); 100 μm (b–d, f–i); 50 μm (a)