Electrical Conductance of Cell-to-Cell Junctions and the Cytoskeleton of Plant Cells

In the submerged trichomes of floating-moss (Salvinia auriculataAubl.) and the roots of the higher water plant Trianea bogotensisKarst., the dependence of the electrical resistance of intercellular junctions on the presence of the agents that destroy microfilaments (cytochalasin B) and microtubules (colchicine) was investigated using the microelectrode technique. The resistance of the junctions (Rc) was estimated taking into account the input resistance and the coefficient of intercellular electrical communication. Should the cells be connected via symplast, Rcwill describe the resistance of plasmodesmata. Cytochalasin B (3–30 μg/ml) reversibly changed Rcduring the first minutes after application. The extent of the change depended on the concentration of the inhibitor; its character of action depended on the initial strength of intercellular communication. When the initial conductance of the contact was high, cytochalasin B elevated the resistance; when it was low, the inhibitor decreased it. In all the experiments, cytochalasin B reduced the input resistance (Ri) that suggests the dependence of plasma membrane resistance on actin cytoskeleton. The effect of colchicine (0.1–1.0 mM) on Riand Rcwas observed only when the cellular membrane was hyperpolarized or after a prolonged action of the inhibitor (for about 0.5 h). It was concluded that the electrical conductance of plasmodesmata and plasma membrane depended on the state of actin cytoskeleton. A complex and probably mediated interaction of microtubules with the processes affecting these characteristics of the cells was suggested.