Morphology and morphological changes of the marine planktonic diatom Thalassiosira allenii Takano (Bacillariophyta) during culture

作者：Hernandez Becerril David U^*; Salazar Paredes Jessica; Baron Campis Sofia A

来源：Nova Hedwigia, 2015, 157-164.

DOI：10.1127/nova_supp1/2015/0036

• cultures
• diatoms
• Mexican Pacific
• morphology
• phytoplankton
• Thalassiosira allenii

The marine planktonic diatom Thalassiosira allenii Takano is commonly distributed in warm waters; however, to date this species had not been reported from the Mexican Pacific. In this paper Thalassiosira allenii, originally isolated and cultured from material obtained from the tropical Mexican Pacific, was studied by light microscope, and scanning and transmission electron microscope. We describe the morphology of T. allenii and also important morphological changes that we observed during culture. The general morphology of the species agrees well with previous descriptions, including the shape of the cells, areola structure and arrangement, and processes: a conspicuous central fultoportula, a rimoportula with a long external tube between valve face and mantle, and a marginal ring of fultoportulae with unusual "urn-shaped" external tubes. Morphological changes of the species during culture included cell enlargement and posterior production of putative reproductive structures, superficially similar to auxospores produced from sexual reproduction, and an evident collapse of the external tubes of marginal fultoportulae of "normal-sized" cells. We have no evidence of spermatogenesis or the presence of siliceous scales on newly produced large cells (mature auxospores), and this could be a case where possible auxospores are produced without sex. We can only speculate on the meaning of the mechanism of collapsing external tubes of the marginal fultoportulae, but it has implications for the putative function of these fultoportulae in Thalassiosira species, as well as taxonomic consequences.

• 出版日期2015