ABSTRACT
Itisusefultodefinethepopulationdoublingtime,td,intermsoftherelativedivision rate.WhenNm(t)/Noisequalto2(foradoubledpopulation),wecansolveEquation 2fortd,or
and
whereInisthenaturallogarithm. Theabovedevelopmentconsiderseachcelltobemeristematic,denotedbythesub-
scriptm,andallcellsarecapableofdivision.NowsupposethatafJfractionofnew cellsaremeristematicandtheremainderarevegetative.Vegetativecellsarecapableof expansionandgrowth,butarenotcapableofdivision.Itisnownecessarytodivide populationnumbersintotwocellclasses:meristematic(Nm(t])andvegetative(N.(t]).
