Within the extreme diversity of aquatic and terrestrial plant genera,
each has characteristic cell wall forms. A number of hypotheses have
been advanced to explain differences in microfibril arrangements across
anyone such wall. Of those, only the 'multinet' theory, which involves
the postulation of reorientation of microfibrils caused by cell
extension, now has a substantial number of ad- herents. However, many
scientists are sceptical of its validity; obviously it is incompatible
with various observed microfibril arrangements. The tenet of this study
is that any such hypothesis can be valid only if it is applicable to all
plant forms and wall types. Initially, reanalyses are made of data
claimed to confirm justification for multi net postulations. The results
show that previous deductions from those data, in support of multinet,
are subject to serious challenge. Similarly, a re-examination of the
observations, which inspired the multinet theory, shows they have a more
logical explanation. Herein, it is concluded that cell wall development
involves biophysical factors, which neces- sarily prevent multinet's
postulated large reorientations of microfibrils, after their formation.
Unfortunately the previously most recent published theory, which is
based on the absence of reorientation during extension, fails to answer
the fundamental question of how alternating orientations between
lamellae are controlled, or explain variations in thickness of wall
layers. Extensive published data are used to identify forces involved in
cell wall development.