Auxin, cytokinin and the control of shoot branching

Background It has been known for many decades that auxin inhibits the activation of axillary buds, and hence shoot branching, while cytokinin has the opposite effect. However, the modes of action of these two hormones in branching control is still a matter of debate, and their mechanisms of interaction are equally unresolved. Scope Here we review the evidence for various hypotheses that have b…