Bunner, Kendra D. , Cook, Martha E. .
Description of Zoospore Structure and Development in Entransia fimbriata (Charophyceae).
Entransia is a member of the charophycean algae, the green algae most closely related to plants. Like other members of the Klebsormidiales, Entransia is an unbranched filament that reproduces asexually through zoospore formation. Sexual reproduction is unknown. Previous evidence had indicated asexual reproduction via zoospores in Entransia, but this is the first time direct observation of the zoospores has been documented in this genus. As is typical for other flagellate cells within the charophycean algae, Entransia zoospores have two flagella and no eye spot. Each zoospore consists of the entire protoplast of the cell from which it is derived. A zoospore escapes through a pore formed in the cell wall and swims in a spiral pattern until it settles and attaches by mucilage to a substrate. The zoospore grows by elongation and cell division into a filament. It was observed that some filaments of Entransia have a spine present on the first settled cell before elongation and cell division begin. As growth continues the spine remains at the tip of the filament. Any cell in a filament of at least two cells in length can produce a zoospore. The formation of these zoospores does not appear to be based on any observable pattern; zoospores can form from the base cell, the terminal cell, and the interior cells. Study of growth and development in Entransia provides an evolutionary perspective that may lead to a greater understanding of these processes in more complex charophycean algae and plants.
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1 - Illinois State University, Department of Biological Sciences, Campus Box 4120, Normal, Illinois, 61790-4120, USA
2 - Illinois State University, Department of Biological Sciences, Campus Box 4120, Normal, Illinois, 61790-4120, USA
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM