The effect of 2,4-D and kinetin on peroxidase activity and isoenzyme pattern in cotyledon cell suspension cultures of bush bean (Phaseolus vulgaris cv. Contender)

Cotyledon cell suspension cultures of Phaseolus vulgaris were grown in the presence and absence of the growth regulators (2,4-dichlorophenoxy)acetic acid (2,4-D) and kinetin. Peroxidase (EC 1.11.1.7) activity was at a minimum during the phase of cell division and at a maximum during the phase of cell expansion. Both the pattern and activity of peroxidase isoenzymes changed during the culture cycle.Cells cultured without growth regulators showed increased peroxidase activity and changed isoenzyme patterns. Certain peroxidase isoenzymes were only present or prominent during specific phases of the culture cycle.The electrophoretic mobilities of peroxidase isoenzymes detected in the medium were not the same as those of the cytoplasmic isoenzymes. Cell cultures grown with and without growth regulators showed different patterns of medium peroxidase activity.Results are discussed in relation to the correlation of peroxidase activity with cell wall expansion and the possible role of peroxidase in cell growth and differentiation.