Microscopic visualization of Pulsed Electric Field induced changes on plant cellular level

The effects of Pulsed Electric Fields (PEF) on protoplasts from cultured tobacco cells (Nicotiana tabacum b.y.-2) in comparison to the changes on cultured plant cells with cell walls were visualised in order to study the direct impact of PEF on cell components and to clarify the influence of the cell wall on electroporation. Optical microscopic analyses were carried out and images were recorded during PEF treatment. Results showed higher sensitivity of protoplasts to electric fields related to cells with a cell wall. Protoplasts sizes were measured before and after different treatment intensities and protoplasts shrinkage was used as an indicator for cell rupture. It could be demonstrated that cell volume decrease is influenced by PEF intensity, initial cell size, cell orientation in the electric field and nucleus position. Industrial relevance: Since the beginning of the 20th century the relevance of Pulsed Electric Fields (PEF) technology in food- and biotechnology has increased substantially. However, the mechanism of membrane permeabilization and the PEF induced changes in cell structure remain poorly understood, diminishing the optimal use in food industry. In this study the direct effects of PEF on cultured plant cell material and influencing factors of the degree of membrane disintegration were visualized and identified. The development of new methods to examine cell vitality shall help to convert the basic knowledge into effective processes. (C) 2010 Elsevier Ltd. All rights reserved.