Role of Membrane-bound, Fixed-charge Changes in Phytochrome-mediated Mung Bean Root Tip Adherence Phenomenon.

The movement of cells and cell fragments in an electric field provided a means for determining the nature of cellular surface charges. We found that changes in ionic strength and particularly changes in Ca(2+) and H(+) in the bathing medium cause changes in the surface charges on the root cap cells in the absence of red light. Red light-induced charge changes are demonstrable only on root cap cells and are reversible with far red light. By osmotically separating the membrane from the wall, we demonstrated that both light-induced and ionically mediated charge changes are associated with the cell membrane and not the cell wall.