Cytoplasmic acidification with butyric acid does not alter the ionic conductivity of plasmodesmata

The effect of lowering cytoplasmic pH on the ionic conductivity of higher-p lant plasmodesmata was investigated with corn (Zea mays L. cv. Black Mexica n Sweet) suspension culture cells. Exposure to butyric acid decreased the c ytoplasmic pH by 0.8 units. Intercellular communication was monitored by el ectrophysiological techniques that allowed the measurement of membrane resi stances of sister cells and the electrical resistance of the plasmodesmata connecting them. The decrease in cytoplasmic pH did not affect the resistan ce of plasmodesmata, despite the fact that the butyric acid treatment more than doubled the concentration of cytoplasmic calcium. This is discussed in light of previous findings that increases in cytoplasmic calcium increase the electrical resistance of plasmodesmata.