Abstract
Cryopreservation technique is very essential to the various fields, such as medical and food engineering. Considering the worldwide food shortage due to the explosive increase of world population and frequently occurring extraordinary climate in near future, the development of cryopreservation technique is desired. Under the above background, we have continued to investigate the load effect of electric current on plant cell in the cooling and freezing processes in order to discuss the possibility of new cryopreservation technique. We had found that the load of electric current influenced on the ice crystal behavior and temperature at the occurrence of intracellular freezing and reported about the results previously. In this research, we investigated how the load of electric current influenced on intracellular pH in the cooling process, focusing on intracellular pH which is one of indicators of cell activity. Helianthus tuberosus L. and Allium cepa L. were used as plants for testing. Intracellular pH was measured using fluorescence intensity ratiometry. As a result, it is clear that the load of electric current causes the reduction in the lowering of intracellular pH in plant with the progress of cooling.
