ABSTRACT
Cellulose fibrils constitute the stiff backbone of the cell wall of higher plants and many algae, especially the Chlorophyceae. They are composed of 8 -1 ,4-linked glucan chains that are assembled into a crystalline entity, the microfibril. The number of polyglucan chains constituting a microfibril depends on the natural habitat and particular growth characteristics of the individual plants, resulting in extensive variation in microfibril width (1 ,2 ) . The relatively thin 7-to 10-nm microfibrils observed in higher plant cells contrast with those found in some algae, which can be 12-30 nm wide. These thick microfibrils were the firs t to be individually visualized (see Figs. 1 - 3 ) .
