120. Hayano, W., Itoh, T., and R. M. Brown, Jr. 1988. Orientation of microtubules during regeneration of cell walls in selected giant marine algae. Plant Cell Physiology 29(5):785-793.
120. Abstract
The microtubules in highly synchronized
aplanospores of Boergesenia forbesii and Valonia ventricosa,
were examined by immunofluorescence microscopy throughout the
regeneration of the cell wall. Microtubule orientation was always
random up to 20 h after wounding, although the orientation of
cellulose microfibrils changed from random to parallel within
that time period. When the rhizoid cells were in the stage of
elongation at 7 to 10 days after wounding, highly ordered microtubules
were always observed along the longitudinal cell axis except
at the very tip of the cells where random ones were found. In
contrast, the microfibrils in the innermost lamellae of newly
synthesized cell walls showed three different orientations, that
is, transverse, longitudinal and oblique to the longitudinal cell
axis. These observations suggest that microtubules may control
cell shape, but not the orientation of microfibrils. The mechanism
of cell wall construction in these algae is discussed in relation
to the self-assembly mechanism thought to operate in the construction
of helicoidal cell walls.