Molecular regulation of phenology in trees-because the seasons they are a-changin'.

The perennial trees, in contrast to the much more studied annual plants, have to adapt their vegetative growth and development to the sometimes extremely contrasting environmental conditions that occur over the different seasons. Recently, studies of the molecular framework underlying this adaptation in Populus trees is reinforcing the notion that the genetic pathways controlling growth and dormancy cycles have a remarkable conservation with the pathways controlling the regulation of flowering time in annual plants. Insight into these mechanisms will be important for our understanding of how trees will respond to various future global climate scenarios.