Figure 6.
Effect of different concentrations of Ca2+ ions on the IAA-induced changes in the Em measured in maize coleoptile parenchymal cells in a medium without K+. Coleoptile segments were incubated in the indicated medium (the same as in growth experiments) for 110 min; afterwards a single segment was transferred into an electrophysiological chamber containing the same medium. Measurements of membrane potential (30 min) were carried out after insertion of a microelectrode into the cell (one cell per one segment) and stabilization of the Em (<10 min) at 2 h (0 min). Indole-3-acetic acid, at a final concentration of 10 µM, was added after 2 h of segment preincubation in the indicated medium; for the last 10 min, coleoptile segments were incubated in the electrophysiological chamber. Representative curves are shown. These curves were fitted with least-squares linear regression and subsequently smoothed using Statistica software for Windows (Version 8.0).