First question should be: what causes the lag phase?
1. Nothing. It is simply a result of the fact that many
of the cells inoculated into fresh medium are dead, i.e. have
turbidity but cannot grow. Thus, one gets a period of "apparent"
2. The need for cells to "condition" fresh medium, by excreting
something, or possibly by many dying and releasing something.
3. The need for certain genes to be induced in order for the
stat phase cell to start growing with fresh nutrients.
I have always thought all of the above would contribute to
what we call lag phase.
Patricia L. Foster
Boston University School of Medicine
Boston, MA USA
pfoster at bu.edu