抄録
Adjacent cellulose microfibrils are thought to be cross-linked by xyloglucans and the separation of microfibrils during elongation has been thought to require enzymes that cleave xyloglucan or loosen its binding to microfibrils. By overexpressing xyloglucanase and producing a knockout mutant of xyloglucan, it would be possible to study the function of xyloglucan in the primary and secondary walls of higher plants. The expression of xyloglucanase constitutively in Populus alba increased the lengths of stem and petiole and enlarged palisade parenchymal cells compacting in the limited space of the leaf. Degradation of xyloglucan network not only decreased the wall elasticity in the elongating stem but also increased the elasticity of secondary xylem. The increased elasticity corresponded to an increase in specific gravity, showing that the degradation of xyloglucan might cause an increase in cellulose density in the secondary xylem.
