title: In vivo analysis of cell division, cell growth, and differentiation at the shoot apical meristem in Arabidopsis.
abstract: The aerial parts of the plant are generated by groups of rapidly dividing cells called shoot apical meristems. To analyze cell behavior in these structures, we developed a technique to visualize living shoot apical meristems using the confocal microscope. This method, combined with green fluorescent protein marker lines and vital stains, allows us to follow the dynamics of cell proliferation, cell expansion, and cell differentiation at the shoot apex. Using this approach, the effects of several mitotic drugs on meristem development were studied. Oryzalin (depolymerizing microtubules) very rapidly caused cell division arrest. Nevertheless, both cell expansion and cell differentiation proceeded in the treated meristems. Interestingly, DNA synthesis was not blocked, and the meristematic cells went through several rounds of endoreduplication in the presence of the drug. We next treated the meristems with two inhibitors of DNA synthesis, aphidicolin and hydroxyurea. In this case, cell growth and, later, cell differentiation were inhibited, suggesting an important role for DNA synthesis in growth and patterning.
authors.affiliation: Institut National de la Recherche Agronomique, Laboratoire Commun de Cytologie, Institut Jean-Pierre Bourgin, 78026 Versailles Cedex, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Grandjean
authors.forename: Teva
authors.initials: T
authors.lastname: Vernoux
authors.forename: Patrick
authors.initials: P
authors.lastname: Laufs
authors.forename: Katia
authors.initials: K
authors.lastname: Belcram
authors.forename: Yuki
authors.initials: Y
authors.lastname: Mizukami
authors.forename: Jan
authors.initials: J
authors.lastname: Traas
mesh_terms: D016590:Aphidicolin / Q000494:pharmacology; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000254:growth & development*; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology*; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D018744:DNA, Plant / Q000187:drug effects / Q000235:genetics; D004136:Dinitrobenzenes / Q000494:pharmacology; D006918:Hydroxyurea / Q000494:pharmacology; D018519:Meristem / Q000166:cytology / Q000187:drug effects / Q000254:growth & development*; D018613:Microscopy, Confocal; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D018520:Plant Shoots / Q000166:cytology / Q000254:growth & development; D013424:Sulfanilamides
chemical_list: D018744:DNA, Plant; D004136:Dinitrobenzenes; D019384:Nucleic Acid Synthesis Inhibitors; D013424:Sulfanilamides; D016590:Aphidicolin; C012465:oryzalin; D006918:Hydroxyurea