title: Meristem size contributes to the robustness of phyllotaxis in Arabidopsis.
abstract: Using the plant model Arabidopsis, the relationship between day length, the size of the shoot apical meristem, and the robustness of phyllotactic patterns were analysed. First, it was found that reducing day length leads to an increased meristem size and an increased number of alterations in the final positions of organs along the stem. Most of the phyllotactic defects could be related to an altered tempo of organ emergence, while not affecting the spatial positions of organ initiations at the meristem. A correlation was also found between meristem size and the robustness of phyllotaxis in two accessions (Col-0 and WS-4) and a mutant (clasp-1), independent of growth conditions. A reduced meristem size in clasp-1 was even associated with an increased robustness of the phyllotactic pattern, beyond what is observed in the wild type. Interestingly it was also possible to modulate the robustness of phyllotaxis in these different genotypes by changing day length. To conclude, it is shown first that robustness of the phyllotactic pattern is not maximal in the wild type, suggesting that, beyond its apparent stereotypical order, the robustness of phyllotaxis is regulated. Secondly, a role for day length in the robustness of the phyllotaxis was also identified, thus providing a new example of a link between patterning and environment in plants. Thirdly, the experimental results validate previous model predictions suggesting a contribution of meristem size in the robustness of phyllotaxis via the coupling between the temporal sequence and spatial pattern of organ initiations.
authors.affiliation: Laboratoire de Reproduction de développement des plantes, INRA, CNRS, ENS Lyon, UCB Lyon 1, Université de Lyon, 46 Allée d'Italie, 69364 Lyon, Cedex 07, France Laboratoire Joliot-Curie, Laboratoire de Physique, CNRS, ENS Lyon, UCB Lyon 1, Université de Lyon, 46 Allée d'Italie, 69364 Lyon, Cedex 07, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Landrein
authors.affiliation: Laboratoire de Reproduction de développement des plantes, INRA, CNRS, ENS Lyon, UCB Lyon 1, Université de Lyon, 46 Allée d'Italie, 69364 Lyon, Cedex 07, France Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1NN, UK.
authors.forename: Yassin
authors.initials: Y
authors.lastname: Refahi
authors.affiliation: Laboratoire de Reproduction de développement des plantes, INRA, CNRS, ENS Lyon, UCB Lyon 1, Université de Lyon, 46 Allée d'Italie, 69364 Lyon, Cedex 07, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Besnard
authors.affiliation: Laboratoire de Reproduction de développement des plantes, INRA, CNRS, ENS Lyon, UCB Lyon 1, Université de Lyon, 46 Allée d'Italie, 69364 Lyon, Cedex 07, France Laboratoire Joliot-Curie, Laboratoire de Physique, CNRS, ENS Lyon, UCB Lyon 1, Université de Lyon, 46 Allée d'Italie, 69364 Lyon, Cedex 07, France.
authors.forename: Nathan
authors.initials: N
authors.lastname: Hervieux
authors.affiliation: Laboratoire de Reproduction de développement des plantes, INRA, CNRS, ENS Lyon, UCB Lyon 1, Université de Lyon, 46 Allée d'Italie, 69364 Lyon, Cedex 07, France Laboratoire Joliot-Curie, Laboratoire de Physique, CNRS, ENS Lyon, UCB Lyon 1, Université de Lyon, 46 Allée d'Italie, 69364 Lyon, Cedex 07, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Mirabet
authors.affiliation: Laboratoire de Reproduction de développement des plantes, INRA, CNRS, ENS Lyon, UCB Lyon 1, Université de Lyon, 46 Allée d'Italie, 69364 Lyon, Cedex 07, France Laboratoire Joliot-Curie, Laboratoire de Physique, CNRS, ENS Lyon, UCB Lyon 1, Université de Lyon, 46 Allée d'Italie, 69364 Lyon, Cedex 07, France Institut Universitaire de France, 103, boulevard Saint-Michel, 75005 Paris, France.
authors.forename: Arezki
authors.initials: A
authors.lastname: Boudaoud
authors.affiliation: Laboratoire de Reproduction de développement des plantes, INRA, CNRS, ENS Lyon, UCB Lyon 1, Université de Lyon, 46 Allée d'Italie, 69364 Lyon, Cedex 07, France.
authors.forename: Teva
authors.initials: T
authors.lastname: Vernoux
authors.affiliation: Laboratoire de Reproduction de développement des plantes, INRA, CNRS, ENS Lyon, UCB Lyon 1, Université de Lyon, 46 Allée d'Italie, 69364 Lyon, Cedex 07, France Laboratoire Joliot-Curie, Laboratoire de Physique, CNRS, ENS Lyon, UCB Lyon 1, Université de Lyon, 46 Allée d'Italie, 69364 Lyon, Cedex 07, France olivier.hamant@ens-lyon.fr.
authors.forename: Olivier
authors.initials: O
authors.lastname: Hamant
mesh_terms: D017360:Arabidopsis / Q000737:chemistry / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D019521:Body Patterning; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism; D018519:Meristem / Q000737:chemistry* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018520:Plant Shoots / Q000737:chemistry / Q000235:genetics / Q000254:growth & development / Q000378:metabolism
chemical_list: D007210:Indoleacetic Acids; D010937:Plant Growth Regulators
keywords: Meristem; morphometry; patterning; phyllotaxis; plastochrone; robustness.