110. Hotchkiss, Jr. A. T., and R. M. Brown,
Jr. 1987. The association of rosette and globule terminal complexes
with cellulose microfibril assembly in Nitella translucens
var. axillaris (Charophyceae). J. Phycol. 23:229-237.
A freeze-fracture investigation of the putative
cellulose synthesizing complex (terminal complex) morphology in
Nitella translucens var. axillaris (A. Br.) R. D.
W. internodal cells revealed single solitary EF globules and PF
rosettes on the plasma membrane. The average density of rosettes
in elongating internodal cells was 5.6 m-2 with slight
spatial variation observed. In only three other algal genera
(all zygnematalean) have rosette/globule terminal complexes been
observed, while this characteristic is common to all vascular
plants and one moss thus far investigated. This evidence strongly
suggests that the rosette type of terminal complex morphology
is an additional characteristic of charophycean algae and lends
further support to the hypothesis that this group of algae represents
the evolutionary line that gave rise to vascular plants. Observations
were also made from the freeze-fracture of Nitella internodal
cells concerning the orientation of cell wall microfibrils and
cytoskeletal elements near the plasma membrane. The pattern of
microfibril orientation in growing internodal cells is initially
transverse to the cell long axis, becoming progressively axial
presumably due to the strain of elongation. In mature internodal
cells, the pattern of microfibril orientation is helicoidal.
Microtubules appressed to the inner surface of the plasma membrane
are oriented parallel to the most recently formed microfibrils
in elongating and mature internodal cells.