Changes in the three dimensional architecture of the cell wall during lignification of xylem cells in Eucalyptus tereticornis

The three dimensional architecture of the cell wall during differentiation of xylem cells in Eucalyptus tereticornis was visualized by rapid-freezing and deep-etching electron microscopy. A highly porous structure was demonstrated in cell corner, middle lamellae and primary walls of both cambium and enlarging xylem cells, but disappeared after lignification of the xylem cells. The porosity of the structure was abruptly diminished by the encrustation of Lignin as well as dense deposition of cellulose microfibrils in differentiating xylem cells. This study is the first to detect rosettes, cellulose synthesising enzyme complexes, in the differentiating xylem cells of a woody plant, and provides the first account of the visualization of the three dimensional architecture of xylem cell walls before and after lignification.