AOBPreview originally published online on October 11, 2004
Annals of Botany 2004 94(6):913-917; doi:10.1093/aob/mch213
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Annals of Botany 94/6, © Annals of Botany Company 2004; all rights reserved
TECHNICAL NOTE |
Statistical Recognition of Random and Regular Phyllotactic Patterns
1 Laboratoire de Cytologie Expérimentale et Morphogenèse végétale, Université Pierre et Marie Curie, Bât. N2, 4 place Jussieu, 75 252 Paris Cedex 05, France and 2 Institut de recherche en biologie végétale, Jardin botanique de Montréal, 4101 Sherbrooke Est, Montréal, Canada H1X 2B2
* For correspondence. E-mail denis.barabe{at}umontreal.ca
Received: 7 June 2004 Returned for revision: 12 July 2004 Accepted: 20 August 2004 Published electronically: 11 October 2004
ABSTRACT
Aims A statistical method used in ecology is adapted to characterize the degree of order in phyllotactic systems.
Scope The test consists of subdividing a planar projection of the stem apical meristem into 16 sectors and counting the number of primordia appearing in each. By dividing the sum of squared deviations by the mean number of primordia per sector the chi-square (
2) is obtained. When there are a total number of 20 primordia, if the
2 is less than 6·26, the phyllotaxis is spiral; if it is between 6·26 and 27·5 the phyllotaxis is random; and if it is greater than 27·5, the phyllotaxis is distichous or whorled (level of significance
= 5 %). It is also possible to remove one or more sectors. If there are k sectors, the two critical values delimiting the random zone will be found in a
2 table for k 1 degrees of freedom.
Conclusions The method is applied to the analysis of sho mutants described by Itoh et al. in 2000 (Plant Cell 12: 21612174). The results obtained are in agreement with the theoretical analysis showing that a whorled or spiral phyllotactic system may contain a certain number of randomly distributed elements without losing its regular global structure.
Key words: Shoot apex, phyllotaxis, models, mutant, chi-square