107. Kudlicka, K., Wardrop, A., Itoh, T.,
and R. M. Brown, Jr. 1987. Further evidence from sectioned material
in support of a linear terminal complex in cellulose synthesis.
Transmembrane linear terminal complexes
considered to be involved in the synthesis of cellulose microfibrils
have been described in the plasma membrane of Boergesenia forbesii.
Evidence for the existence of these structures has been obtained
almost exclusively using the freeze etching technique. In the
present study an attempt has been made to complete these studies
using conventional fixation, staining, and sectioning procedures.
In developing cells of Boergesenia forbesii, strongly
stained structures traversing the plasma membrane and averaging
598.9 nm 171.3 nm in length, 28.7 nm 4.2 nm in width, and 35.2nm
6.6nm in depth have been demonstrated. These structures are
considered to be linear terminal complexes. At their distal (cell
wall) surface, they appear to be closely associated with cellulose
microfibrils. At the proximal (cytoplasmic) surface, they are
associated with microtubules and polysomes. A model of the possible
interrelation of the terminal complexes and microtubules leading
to the generation of cell wall microfibrils is proposed.