Mechanisms of Age-Dependent Response to Winter Temperature in Perennial Flowering of Arabis alpina

Multiple Inputs to Flowering Perennial plants need to cycle through an extended vegetative phase, in a process known as vernalization, before they initiate flowering. Bergonzi et al. (p. 1094 ) and Zhou et al. (p. 1097 ) studied how molecular signals translate environmental information—such as exposure to a winter season or changes in daylength and physiological information, such as age of the plant—into signals that promote flowering. In both Arabis alpina and Cardamine flexuosa , age and vernalization pathways are integrated through the regulation of microRNAs miR156 and miR172.