Effect of Extracellular Peroxidases on Growth of Carrot and Sugar Beet Suspension Cells

Abstract

It is generally accepted that an increase in peroxidase activity is temporally correlated to a decrease in growth rate of plant cells. The growth of embryogenic suspension cells of carrot was found to be inversely correlated to the peroxidase activity secreted into the growth medium. Due to the extracytoplasmic localization of the majority of peroxidase activity of suspension cells, horse radish peroxidase (HRP) was added to the growth medium of suspensions of embryogenic carrot cells and habituated sugar beet cells and the effect on the growth rate was measured. The added HRP activity was 10 to 200 fold higher than the physiological activity and it persisted throughout the growth period. The peroxidase activity secreted from the carrot suspension cells was not affected by the presence of added HRP activity. The added HRP activity did not reduce the growth of the suspension cells.