The effect of an osmotic shock on the subsequent growth and cell wall texture was studied at 0, 1/2, 1, 2, 4 and 24 hours. Cells were taken at the beginning of their exponential growth from mung bean hypocotyl.
The shock reveals the instability and the fragility of the assembly mechanisms. It induces a rupture in the texture (formation of a loose layer) or, occasionally, the apparition of a swirling pattern. After the shock, the twisting positioning can be restored. The
post-shock
deposit appears similar to the
pre-shock
deposit. The loose layer provides a visible guide-mark (time marker) within the wall. It allows one to evaluate the oscillatory period (
i.e., the duration necessary for a 180° rotation of the microfibrils). This period was found to be ca. 3 hours following a lag period of ca. 1 hour. It confirms the endogenous ultradian character of the rhythm of the assembly.
Keywords Cell wall - Growth - Osmotic shock - Rhythm - Twisted assembly