Root hair growth in Arp2/3 mutants is disturbed; root hairs of
these mutants are somewhat wavy and have a variable
diameter. All these effects point to actin cytoskeleton defects,
such as less or mislocalised fine F-actin [91,93,95–99].
Summarising, the Arp2/3 complex seems to be involved in
the organisation of the subapical fine F-actin array in rapidly
growing cells (dark-grown hypocotyl epidermal cells) or cells
with cell expansions that take place over a limited surface
area (trichomes, root hairs and leave epidermal cells), but its
role does not seem to be of major importance in other cell
types. The Arp2/3 complex is therefore hypothesized to only
contribute to the nucleation of a small fraction of the total Factin
within higher-plant cells [92].