Caracteacute;risation des types cellulaires cladomophore et pleuridiophore chez la rhodophyceacute;e ceacute;ramiaceacute;eAntithamnion plumula: apport de l'analyse des cineacute;tiques de croissance

摘要

The analysis of the elongation kinetics of the cladomophoric and pleuridiophoric cell types inAntithamnion plumula(Ellis) Thuret was carried out using a bilogistic model (the sum of two nonsynchronous generalized logistics). The growth structure or discretization of the growth pattern into a series of phasesGi, defined by the paired values, absolute speed (V) - acceleration (Ggr;), was inferred. The growth structure was qualitatively similar in the two cell types {G1,G2,G1,G2,G3,G4} although, quantitatively, clear differences appeared. The pleuridiophores were distinguished from the cladomophores by the greater importance of the first phasesG1andG2(i.e., increasing, then decreasing positive acceleration, respectively). Likewise, during these two phases, the specific growth rate,R, was significantly higher in the pleuridiophores. According to the cell type, there are thus, independently of possible differences in size, differential properties of a strictly kinetic order in the elongation process. These data mean that at the beginning of their growth, the pleuridiophoric cells are in a "juvenile" condition, whereas the cladomophoric cells are relatively in a more "mature" state. A biological interpretation is put forward.Key words: Rhodophyceae,Antithamnion, cell growth, growth kinetics, logistic model, morphogenesis.