The Role of Membrane Potential for the Control of Elongation Growth of Vigna Hypocotyl: Response of a Hollow Cylinder to Osmotic and Ionic Stress |
| |
Authors: | Nakahori Kiyoshi; Katou Kiyoshi; Okamoto Hisashi |
| |
Institution: | Biological Institute, Faculty of Science, Nagoya University Furo-cho, Chikusa-ku, Nagoya 464, Japan |
| |
Abstract: | We have devised an experimental system of perfusion througha hollow cylinder of a Vigna hypocotyl to examine the controlmechanism of plant stem elongation. When the cylinder was subjectedto osmotic stress, it began to shrink and then spontaneouslyresumed elongation. Not only the membrane potential differencebetween the parenchyma symplast and the central bore (Vpx),but also that between the parenchyma symplast and the organsurface (Vps), showed hyperpolarization a few minutes afterthe cylinder began to shrink. Removal of the stress caused animmediate increase in elongation rate followed by depolarizationof both membrane potentials a few minutes later. When the cylinderwas subjected to KCl stress, Vpx showed transient depolarizationand recovery, while Vps showed only immediate hyperpolarization.Increasing the KCl concentration caused Vpx to depolarize, andthe cylinder simultaneously to cease to elongate for about 5min,even when the osmotic concentration of the perfusion solutionwas kept almost constant. An inverse reaction was observed whenthe KCl concentration was decreased. These two reversible responses suggest that control of Vpx mayregulate the elongation of hollow cylinders, and that the xylempump plays an important role in the regulation of intact stemelongation. (Received January 7, 1987; Accepted April 30, 1987) |
| |
Keywords: | |
本文献已被 Oxford 等数据库收录! |
|