Figure 1.

Suberin deposition patterns in soybean roots. A to G, Free-hand cross sections of soybean roots. Bars = 100 μm. A, Autofluorescence of outer epidermal walls (arrowheads), 10 mm from root tip. B, Autofluorescence of epidermal walls (arrowheads) and cortical walls (arrows), 50 mm from root tip. C, Yellow-green fluorescing walls of epidermis (arrowheads) stained with FY, 20 mm from root tip. D, Section taken 90 mm from root tip and stained with FY. Note yellow fluorescence in walls of epidermis (arrowheads) and cortex (arrows). E, Cell walls remaining after acid digestion, 50 mm from root tip. All walls of the epidermis are present (arrowheads), as are the walls of most adjacent cortical cells (arrows). F, Section stained with toluidine blue 0 and neutral red 7B, 30 mm from root tip. Casparian bands (arrowheads) are present in the endodermis. G, Section stained with FY, 100 mm from root tip. Patches of cells with suberin lamellae (arrowheads) are present in the endodermis. H to J, Scanning electron micrographs of enzyme-digested root segments, longitudinal views. Bars = 100 μm. H, Inner side of epidermis, 15 mm from root tip. Outer tangential walls (arrows) and anticlinal walls (arrowheads) are present. I, Inner cortical side of epidermis and cortex, 45 mm from root tip. Outer tangential cortical walls (arrows) and anticlinal walls (arrowheads) are visible. J, Endodermis, 100 mm from root tip. Anticlinal walls of cells with Casparian bands only (arrow) form a net-like structure. Endodermal walls with suberin lamellae appear solid (arrowheads). K and L, Whole mounts of tissues isolated from a root segment by enzymic digestion and stained with FY, 110 mm from root tip. Bars = 500 μm. K, Strip of epidermis and associated cortex. Fluorescence is rather even. L, Entire endodermis. Cylinder was cut longitudinally to form a sheet that became twisted. Fluorescence is bright in four strips correlating with patches of cells with suberin lamellae.