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Structure and Development of the Auxospore in Ardissonea crystallina (C. Agardh) Grunow Demonstrates Another Way for a Centric to Look Like a Pennate.
Protist ; 169(4): 466-483, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30025232
Reproductive development in Ardissonea crystallina revealed a unique mode of enlargement involving a combination of novel and known structures. In light microscopy, auxospores of this elongated polar centric diatom were superficially similar to the auxospores of pennates. With SEM we found three different components in the auxospore wall. In the youngest, nearly spherical cell-stage, the wall consisted only of a delicate veil containing minute siliceous spherules. Incunabular elements developed underneath this layer. Second, a previously unknown form of specifically modified incunabular scales shaped the subsequent ellipsoidal-capsule auxospore stage. Third, there was a clear contribution of scales to the development of scaly transverse perizonial bands (or scaly bands, for brevity). Such bands, although noted by previous researchers, have not been fully appreciated for the evolutionary information they may convey: possibly common among polar centrics but not pennates. Finally, we propose maintaining the term transverse perizonium to refer to these bands in polar diatoms, but to introduce the differentiation of scaly bands described here from pinnate bands (currently known as typical of pennates). Further research into band types among polar centrics may provide new insights into the relationship between the groups within polar centrics that are currently unresolved by molecular methods.





Texto completo: Disponível Coleções: Bases de dados internacionais Base de dados: MEDLINE Assunto principal: Diatomáceas Idioma: Inglês Revista: Protist Assunto da revista: Biologia / Parasitologia Ano de publicação: 2018 Tipo de documento: Artigo