Dormant meristems of Allium cepa L. root begin to sprout as soon as the water and temperature conditions are right. These cell systems offer many advantages when studying the earliest metabolic events related with the onset of the cell proliferating activity. By electrophoresis in SDS polyacrylamide gels the soluble protein fraction from meristems with increasing imbibition times was analysed. There are qualitative constancy and quantitative differences between electrophoretic patterns from dormancy to steady state conditions. It is suggested that polypeptide 8a, approximately 80,000 daltons in molecular weight, be considered an indicator of proliferative activity in the meristem.