Les premiers stades de la formation de I’ébauche de nageoire pelvienne de Truite(Salmo farioetSalmo gairdneri): III—Capacités de régulation

Abstract

ABSTRACTThe first stages of genesis of the pelvic fin aniage in the trout (Salmo fario and Salmo gairdneri). III. Regulation capacitiesIn S. fario and S. gairdneri, microsurgical excisions of parts of pelvic fin-buds showed the important regulation capacities of the fin anlage. At the stages studied, a complete unilateral excision is generally not followed by a regulatory response. On the contrary, a unilateral partial excision performed at the same developmental stages is followed by a regulatory response. Bilateral excisions of the fin-buds, performed at earlier developmental stages than unilateral ones (and at a slightly different level for mesoderm) are followed by regulation.The results are discussed in this article. It appears that the mesoderm is a determining factor in the development of the fin-buds; the epidermis does not appear influential -at least in the first stages of regulation.We noticed a higher percentage of regulation in S. gairdneri than in S. fario’, the results obtained are analysed with regard to histoenzymological data.