Fig. 2.

Development of apoplastic barriers in roots. Fully developed Casparian strips (blue dots marked with white arrows) in the exodermis (a) and endodermis (c) stained with Berberine hemisulphate, and suberin lamellae (white or yellow-framed cells) in the exodermis (b) and endodermis (d) of S. caprea roots stained with Fluorol yellow 088. Some passage cells in the endodermis (non stained cells marked with white arrows) that are oriented opposite to the xylem poles (blue) can be still observed (d). Abbreviations: rh – rhizodermis, ex – exodermis. Bars, 50 μm. Schemes of the development of Casparian strips (e,f, green lines) and suberin lamellae (g,h, red lines) in exo- and endodermis of the root of S. caprea isolates F20 (e,g) and KH21 (f,h). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)