[Effect of R-plasmids on the type of growth of Escherichia coli]

The effect of plasmids belonging to four incompatibility groups on the lag phase duration and the growth rate of E. coli was studied. The lag phase was much longer in the presence of plasmids belonging to the IncP and IncI groups in E. coli cells. No correlation in growth rate changes was found between plasmid strains and those which did not contain plasmids.