Developmental and Structural Section
Zalamea, Paul Camilo , Heuret, Patrick , Stevenson, Pablo , Madriñan, Santiago .
Determination of growth pattern and age in the South American tropical tree Cecropia sciadophylla Mart.
The genus Cecropia Loefl. includes around a hundred neotropical species, ranging from Mexico to Northern Argentina and the West Indies. These species are pioneer trees that colonize cleared areas and open areas with high light levels. As the trees are associated with the initial stages of forest succession, determining their age can help to pinpoint the date of the disturbance that prompted their establishment. For this purpose, it is necessary to understand the dynamics of their development and architecture over time. Cecropia spp. have a very simple architecture and conform to Rauh’s architectural model (the axes are orthotropic, with lateral flowering and rhythmic branching). Their axes are made of a succession of nodes and internodes whose length and associated lateral productions remain visible and measurable over years. We focused in this work on Cecropia sciadophylla that is present in the Amazon basin, the Guiana region, and the Llanos region in Colombia. In two stations (in French Guyana and Colombia), we described the trunk of 26 trees node by node as sequences of events recording (i) the internodes length, (ii) the presence of branches, (iii) the presence of flowers. Using autocorrelation coefficients reveals a high periodicity with inflorescences regularly occurring every 25 nodes, stages of branches spaced by a multiple of 25 nodes and alternation of long and short nodes every 25 nodes. Considering that flowering is annual for many species of this genus, the main conclusion of this work is the existence of a strong annual rhythm in growth, branching and flowering processes in this tropical species and the possibility to estimate retrospectively the age of the tree by observing its morphology.
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1 - Ciem, Departamento de Ciencias Biológicas, Universidad de los Andes, Cr. 1a No. 18A-10, Bogotá, Colombia
2 - Inra, U.M.R botanique et bioinformatique de l'architecture des plantes (AMAP), TA A-51/Ps2, Montpellier Cedex 5, 34398, France
3 - Universidad de los Andes, Departamento de Ciencias Biológicas, Apartado Aéreo 4976, Bogotá, Cundinamarca, Colombia
Presentation Type: Poster:Posters for Sections
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM