Data/hora: 04/06/2024 10:10:09

Provedor de dados: 	5	
País: 	France	
Título: 	Etude cytologique de la gamétogenèse, de la sex-ratio et du cycle de reproduction chez l'huître perlière Pinctada margaritifera (L) var. cumingii (Jameson), (mollusques, bivalves). Comparaison avec le cycle de Pinctada maculata (Gould)	
Autores: 	Thielley, Maryse.	
Data: 	1993-04-22	
Ano: 	1993	
Palavras-chave: 	Gamétogenèse; Cycle de reproduction; Sex-ratio; Pinctad margaritifera; Mollusque; Bivalve; Huître perlière; Gametogenesis; Reproductive cycle; Sex-ratio; Pinctada margaritifera; Mollusca; Bivalvia; Pearl oyster.	
Resumo: 	The population of Pinctada margaritifera and Pinctada maculata lay eggs throughout the year. Temperature variations induce huge but asynchronous laying. Preferential periods of gonad maturity correspond to the season changings in both species. However. some differences between the two specics are noticed. Both species are protandric hermaphrodites. Female condition is unstable: a reversion to the male condition may be observed and is probably linked with stress. The average size for the first sexual maturation as weil as for sexual conversion are specified in P. margaritifera. The breeding conditions induce modifications in some reproductive cycle processes (maturation, sex-ratio). Some conditions suitable for reproduction may become unfavorable to development or merely maintaining P. margaritifera populations. This should be taken into account for the further developmcnt of perliculture in French Polynesia. The ultrastructural cytological evolution of sexual cells is described in P. margaritifera for both sexes, from stem cells to mature gametes. Some particularities against general observations in other bivalvia are underlined, especially: - the presence of auxiliary cells in both sexes, with their possible trophic role and participation in vitelline envelope elaboration. - the likely glycolipid nature of type Il vitellinic inclusions. - frequent cytological abnormalities, especially in the male lineage. Analysis of the soma tic environment of the gametes discl oses the presence of: 1) mucocytes, which may have a non negligiblerole in the nutrition process allowing the adaptation of this species toits oligotrophic milieu; 2) granular cells the role of which is discussed. Degenerative processes and gamete resorption are described. at the ultrastructural level	
Tipo: 	Text	
Idioma: 	Francês	
Identificador: 	http://archimer.ifremer.fr/doc/00440/55208/56677.pdf

http://archimer.ifremer.fr/doc/00440/55208/	
Editor: 	Université Française du Pacifique	
Formato: 	application/pdf	
Fonte: 	1993 Université Française du Pacifique

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