Abstract: Changes in levels of peroxidase isozymes during in vitro adventitious bud formation from leaf explants of Rubus laciniatus wild. were investigated by means of disc acrylamide gel electrophoresis. The overall level of peroxidase isozymes increased four to eight times and the enzyme activity increased from 0.24 OD/min to 1.82 OD/min during the process of differentiation in vitro. In addition, various growth regulators had different effects on the level of peroxidase during adventitious shoot formation. Without growth regulators, there was little change in the level of peroxidase isozymes and no shoot differentiation. The relationship of enzyme activity to gene activity and cellular differentiation is discussed in this paper.