Studies on Mechano-perception in the Characeae: Transduction of Pressure Signals into Electrical Signals.

Teruo Shimmen

Mechanoperception by Chara cells was studied with an emphasis on the role of the nodal complex in transducing pressure signals into electrical signals. Three types of experimental material were used: (1) tandem internodal cells connected by a single layer of nodal cells; (2) single internodal cells, from which either apical or basal nodes were removed by ligation and cutting; (3) single internodes from which both nodes had been removed. Exposure to a hypertonic solution (sorbitol or sucrose) induced a depolarization at the node in 1 and 2. Depolarization did not occur at the ligated end of the cell in 2, or at all in 3. Addition of K increased the magnitude of the response, whilst it was significantly decreased by the divalent cations, Ca2 and Mg2 . Electrical resistance decreased at the node during the depolarization, showing that a passive diffusion potential was responsible. I suggest that the change in the trans-nodal hydraulic pressure difference mechanically stretches the plasma membrane, and this induces the electrical depolarization.

MECHANORECEPTORS; CHARACEAE; GENETIC transduction; CELLS

Plant & Cell Physiology, 2003, Vol 44, Issue 11, p1215

0032-0781

Academic Journal

10.1093/pcp/pcg151