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Free keywords:
plasmodesmata, shoot branching, callose, buds, phloem, companion cells
Abstract:
Abstract Shoot branching involves the coordinated regulation of the activity of meristems established in the axils of leaves along the stem (Mcsteen and Leyser, 2005). Once established, such axillary meristems often arrest as a dormant bud after the production of a few leaves. The hormone auxin, produced in the shoot apex, plays a central role in this process by moving downward in the stem and maintaining these axillary meristems in an inactive state, a process termed apical dominance (Morris, 1977, Snow, 1925, 1929). Since auxin does not itself enter the buds, the auxin transport canalisation model for bud regulation was postulated (Li and Bangerth, 1999; Bennett et al. 2006). According to this model, each bud, acting as an auxin source, must establish canalised auxin export in order to grow.