title: Time-lapse imaging of Arabidopsis leaf development shows dynamic patterns of procambium formation.
abstract: The principles underlying the formation of leaf veins have long intrigued developmental biologists. In leaves, networks of vascular precursor procambial cells emerge from seemingly homogeneous subepidermal tissue through the selection of anatomically inconspicuous preprocambial cells. Understanding dynamics of procambium formation has been hampered by the difficulty of observing the process in vivo. Here we present a live-imaging technique that allows visual access to complex events occurring in developing leaves. We combined this method with stage-specific fluorescent markers in Arabidopsis (Arabidopsis thaliana) to visualize preprocambial strand formation and procambium differentiation during the undisturbed course of development and upon defined perturbations of vein ontogeny. Under all experimental conditions, we observed extension, termination and fusion of preprocambial strands and simultaneous initiation of procambium differentiation along entire individual veins. Our findings strongly suggest that progressiveness of preprocambial strand formation and simultaneity of procambium differentiation represent inherent properties of the mechanism underlying vein formation.
authors.forename: Megan G
authors.initials: MG
authors.lastname: Sawchuk
authors.forename: Philip
authors.initials: P
authors.lastname: Head
authors.affiliation: Department of Biological Sciences, University of Alberta, CW-405 Biological Sciences Building, Edmonton AB, T6G 2E9 Canada.
authors.forename: Tyler J
authors.initials: TJ
authors.lastname: Donner
authors.affiliation: Department of Biological Sciences, University of Alberta, CW-405 Biological Sciences Building, Edmonton AB, T6G 2E9 Canada.
authors.forename: Enrico
authors.initials: E
authors.lastname: Scarpella
mesh_terms: D017360:Arabidopsis / Q000254:growth & development*; D005456:Fluorescent Dyes; D015870:Gene Expression; D007210:Indoleacetic Acids / Q000378:metabolism; D008856:Microscopy, Fluorescence; D052585:Phloem / Q000254:growth & development; D018515:Plant Leaves / Q000254:growth & development*; D013997:Time Factors; D052584:Xylem / Q000254:growth & development
chemical_list: D005456:Fluorescent Dyes; D007210:Indoleacetic Acids