Figueroa, R.I. (Rosa Isabel)

English

Sexual reproduction of Gymnodinium nolleri (Ellegaard & Moestrup 1999) was studied by intercrossing experiments in all combinations of six clonal strains and backcrossing of five clonal F1 offspring. The results indicated that the conjugation of G. nolleri responded to the existence of more than two sexual types (complex heterothallism) and that compatibility between progeny of one cyst (inbreeding) was the rule. Sexual fusion, planozygote formation and development, cyst formation, and germination and planomeiocyte division were followed using time-lapse photography. This study revealed many similarities between the sexual stages and life cycle pattern of G. nolleri and the related G. catenatum and the existence under culture conditions of an alternative cycle between vegetative cells and zygotes without a hypnozygote stage. The fate of zygotes, division or encystment, was influenced by the nutritional status of the external medium. The division of G. nolleri planozygotes was promoted by high levels of external nutrients, whereas the maximum percentage of encystment was recorded when phosphates were reduced in the isolation medium. The division of zygotes might be different from both vegetative and planomeiocyte division because it resulted in two-cell chains with the cells not oriented in parallel.S

Figueroa, Rosa Isabel

Digital.CSIC

Journal of Phycology

A study of the sexual reproduction and determination of mating type of gymnodinium nolleri (Dinophyceae) in culture

Sexual reproduction of Gymnodinium nolleri (Ellegaard & Moestrup 1999) was studied by intercrossing experiments in all combinations of six clonal strains and backcrossing of five clonal F1 offspring. The results indicated that the conjugation of G. nolleri responded to the existence of more than two sexual types (complex heterothallism) and that compatibility between progeny of one cyst (inbreeding) was the rule. Sexual fusion, planozygote formation and development, cyst formation, and germination and planomeiocyte division were followed using time-lapse photography. This study revealed many similarities between the sexual stages and life cycle pattern of G. nolleri and the related G. catenatum and the existence under culture conditions of an alternative cycle between vegetative cells and zygotes without a hypnozygote stage. The fate of zygotes, division or encystment, was influenced by the nutritional status of the external medium. The division of G. nolleri planozygotes was promoted by high levels of external nutrients, whereas the maximum percentage of encystment was recorded when phosphates were reduced in the isolation medium. The division of zygotes might be different from both vegetative and planomeiocyte division because it resulted in two-cell chains with the cells not oriented in parallel

Repositorio Institucional Digital del IEO

http://www.repositorio.ieo.es/e-ieo/bitstream/10508/11132/1/3_Figueroa%20and%20Bravo%202005%20Nolleri.pdf

A study of the sexual reproduction and determination of mating type of gymnodinium nolleri (Dinophyceae) in culture

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Digital.CSIC

Repositorio Institucional Digital del IEO