Abstract
G-fiber exists in only tension wood. Typical tension wood is characterized by this cell. It has a characteristic layer which contains no lignin, named G-layer. Tension wood is formed in the upper side of leaning stem of angiosperm. Tension wood causes the stem to bend upwards by its mechanical action induced by the tensile growth stress. However, the mechanism how tensile stress occurs in tension wood is still unknown. Xylogolucan, which does not occur in the secondary wall of normal wood, was found in the G-fiber of poplar tension wood. In order to reveal the localozation of this polysaccharide in the G-fiber, transverse sections were observed with immunocytochemical treatment. The signal that shows the antibody binding was found at the inner-most of the G-layer during the fiber development. Mature G-layer did not show the affinity to the antibody. This result shows that xyloglucan is involved in G-layer formation.
