Physiological actions of brassinosteroids: An update

In general, this overview covers literature from 1999 until early 2003. Topics covered include aspects of the biosynthesis and transport of brassino-steroids, their effects on cell division, expansion, and differentiation, and their effects on whole plants, including source-sink relations and other endogenous interactions. Some interactions with environmental signals are discussed, as well as results that may promise applications in future. Topics that warrant further investigation of the roles of BRs include phenotypic variability, reproductive physiology, senescence, branching, and apical dominance, whereas topics in which possible roles for BRs are relatively unexplored include lignification, phototropism, photoperiodism, and endogenous rhythms.