Electrical breakdown of protoplast membranes under different osmotic pressures

• Published in: Bioelectrochemistry and Bioenergetics Vol. 19; no. 2; pp. 217 - 225
• Main Authors: Zhelev, D.V., Dimitrov, D.S., Tsoneva, I.
• Format: Journal Article
• Language: English
• Published: Elsevier S.A 01.06.1988
• ISSN: 0302-4598
• DOI: 10.1016/0302-4598(88)80003-5

The electrical breakdown of membranes depends on their tension. The cell membrane tension increases with decreasing osmolarity of the solution. We measured the breakdown voltage of pea protoplasts in hypo-, iso- and hypertonic mannitol solutions. In hypotonic solutions, near the isotonic point, the breakdown voltage decreased strongly with increasing osmotic pressure difference. For lower osmolarities, the breakdown voltage did not change so significantly. In hypertonic solutions, the protoplasts broke at the same voltage as in isotonic ones. We developed a theory, based on the fluctuation waves mechanism of membrane rupture, which describes the experimental results approximately. It does not, however, fit the data for solutions of low osmolarity. Possible mechanisms, not taken into account by the theory, and applications to biotechnology are discussed.