The role of local biosynthesis of auxin and cytokinin in plant development.

Plant hormones are tightly regulated in response to environmental and developmental signals. It has long been speculated that biosynthesis of hormones occurs broadly in plant organs and that intricate, spatiotemporal regulation of hormones in developing organ primordia is achieved through transport and signal perception. However, recent identification of genes crucial for biosynthesis of auxin and cytokinin reveals that localized hormone biosynthesis also plays an important role in organ growth and patterning.