Fig. 1

Hypocotyl grafting: (I) schematic representation of the following stages and (II) important morphological features. a and inset – graft union with callus cells (arrowheads), local increase in the circumference of the scion (arrows). b – scion, cut surface covered with extracellular material (arrowheads). c – epidermal cells, increased staining of the cytoplasmic compartments (arrows and arrowhead). d – stable graft union (arrowhead), developing adventitious root (arrow). e – tracheary elements (full arrows), sieve elements (arrowhead), and meristematic cells (arrows). f – graft union (arrowhead), dotted line – site of the cut. g – bluish autofluorescence of polyphenolic compounds present in the walls of the endodermal (arrows) and peripheral cells of the graft union (arrowheads); pink – autofluorescence of chlorophyll. h – lipid substances stained red and detected in the walls of the endodermal (arrows) and peripheral cells of the graft union (arrowheads), asterisk – graft union area. Cor cortex, dag days after grafting, en endodermis, ep epidermis, sc scion, st (root)stock, TBO toluidine blue O, te tracheary elements. Scale bars: a, a inset, d, and f = 200 μm; g = 100 μm; h = 50 μm; b, c, and e = 10 μm