Changes in cellular Ca2+ influx and efflux measured in root hairs in response to actin-acting drugs treatments. The data were obtained using non-invasive scanning ion-selective electrode measurements, which were taken at predefined locations (apex of root hair), with the Ca2+ selective probe positioned 2 μm from the root hair surface. (A) Lat-B treatment induced a rapid increase in extracellular Ca2+ influx, followed by obvious net efflux after 5 min. (B) Jas treatment induced a lasting increase in extracellular Ca2+ influx within the first 5 min, followed by obvious net efflux. Positive values represent Ca2+ efflux while negative values represent influx.