The Meristem-Meristem Cycle as a Basis for Defining Fitness in Clonal Plants

Abstract

In clonal plants the genetic individual may be exceedingly long-lived, and the traditional way of defining Darwinian fitness − i.e. on the basis of the zygote-zygote cycle − may therefore be impracticable. Yet, an obvious alternative, viz. to define fitness on the basis of the meristem-meristem cycle, has frequently been rejected. I suggest here that this rejection is unwarranted, and I present a quantitative measure of fitness in clonal plants that I consider to be of general applicability. Meristems are considered to have three developmental options : (i) to propagate vegetatively; (ii) to propagate sexually; (iii) to remain dormant. Each option leads to the perpetuation of the genome of a mother meristem from the time t 1 , to daughter meristems at the time t 2 ; in the case of option (ii) a gene runs a risk of getting lost through meiosis (...)