Abstract
Membrane depolarization induced by transcellular osmosis was studied using internodal cells ofNitella flexilis. Transcellular osmosis was induced by using sorbitol or methanol as the osmotic agent. In the endosmotic cell half, the membrane often generated an action potential and depolarized further with a concomitant decrease in membrane resistance. This osmosis-induced depolarization was a graded response dependent on the external osmotic gradients. However, in the exosmotic cell half, both membrane potential and membrane resistance changed insignificantly. Membrane depolarization occurred also in cells made inexcitable by bathing in 0.1–1 mM KCl solution. Effects of temperature and internal osmotic pressure on osmosis-induced depolarization were investigated. The magnitude of depolarization at low temperature (2 or 4°C) was larger than that at room temperature (around 20°C). Membrane depolarization was accelerated by lowering the internal osmotic pressure and inhibited by raising it. Not only the plasmalemma but the tonoplast also responded significantly to endosmosis.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.