Fig. 3

Immunolabelling of adventitious roots during development – pectin epitopes. a Initial stage, LM20 epitope in walls between the cambium/initial cells/cortex (arrows), weak signal in division walls (open arrows). b Punctate (open arrows) or continuous (arrowheads) distribution as divisions proceed, abundant occurrence at AR/cortex boundary, in the walls and intercellular spaces of cortex (arrows). c LM20 present in the extracellular layer (arrow); inset: magnification of c (asterisk), weak signal in primordium. d Initial stage, LM19 epitope present in initials (open arrow) and multicellular complex (arrow); inset: magnification of d (circle), weak signal in the division walls (open arrow) in contrast to the walls of the cell complex (arrow). e Cortex adjacent to a developing root, LM19 localised in the walls, middle lamellae (arrow) and intercellular spaces (open arrow). f LM19 epitope abundant in the ground tissue (arrows) in contrast to the central region (asterisk) and epidermis (open arrow), strong labelling in the cortex walls, intercellular spaces and the extracellular layer (arrowheads); inset: magnification of f (asterisk), epitope distribution (arrows). g, h the extracellular layer. i. Parenchyma next to an LR primordium (arrow) and thickening of the extracellular matrix (open arrow). i’. i fluorescence, LM8 epitope present in the cortical cells adjacent to a primordium (arrow). j LM8 between the root and scion (arrow), no fluorescence signal in sections without contact (open arrow). k LM8 in the rhizodermis (arrows). l Magnification of k (circle), LM8 detected in the outer periclinal walls (arrow) and a weak signal in the anticlinal walls (arrowhead). m Root cap, LM8 present in the outer periclinal walls (arrow), weak signal in the inner cells (open arrow). ar – adventitious root, c – cambium, col – collenchyma, cor – cortex, f – fibre, rc – root cap, sc – scion. Scale: 100 μm(k), 50 μm (f, i, j, inset i), 20 μm (a-e, g, l, c inset, d), 10 μm (h, m, f inset)