Relationship between growth of parsley and soybean cells in suspension cultures and changes in the conductivity of the culture medium.

Changes in conductivity and pH during the growth cycle of cell suspensions derived from parsley (Petroselinum hortense) and soybean (Glycine max) have been investigated. Measurement of the conductivity of the medium represents a simple, rapid, and reliable method for the precise determination of the growth phase of a culture. The accuracy of this method has been tested by using phenylalanine ammonia-lyase, an enzyme that has a characteristically short, distinct period of activity during the growth cycle of soybean cell suspensions. It is suggested that an automatic regulation of the conductivity of the medium might be employed for growing plant cells in a continuous culture at a defined stage of growth.