Temperate woody perennials become dormant over winter; but dormancy is also a prerequisite for adequate flowering, thus limiting their cultivation at warmer latitudes. Julian et al. show that dormancy appears to mark a boundary between the development of the sporogenous tissue in stamen and the occurrence of meiosis for further microspore development in apricot, Prunus armeniaca. Breaking of dormancy occurs following a clear sequence of events, providing a developmental context in which to study winter dormancy and to evaluate differences in chilling requirements among genotypes.
