Ultrastructural Study of Zoosporogenesis in the Siphonous Green Alga Derbesia tenuissima (Chlorophyta)
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S.-H. Lee
Abstract
Based on transmission electron microscopy observation, zoosporogenesis in the siphonous multinucleate green alga Derbesia tenuissima can be divided into five stages. In vegetative sporophytes and Stage 1 sporangia, the cytoplasm was distinguished as two regions, the inner region of chloroplasts and the outer region of nuclei. In Stage 1 sporangia, the chloroplasts differentiated into amyloplasts and contained large starch grains. In Stage 2 sporangia, several meiotic nuclei with synaptonemal complexes were observed in the apical and the subapical portions of a sporangium. The width of a synaptonemal complex was 103±5 (mean ± standard deviation) nm (n = 20). In Stage 3 sporangia, the plug complex that was composed of 4 layers as observed with transmission electron microscopy, was formed between the sporangium and the main axis. In Stage 4 sporangia, the following conspicuous characters were observed: 1) differentiation of nuclei into two types, 2) de novo appearance of centrioles (flagellar basal bodies) on the type 2 nuclei (large), 3) decrease in the number of the type 1 nuclei (small), 4) development of cleavage furrows and vesicles, 5) formation and elongation of flagellar axonemes, and 6) development of three characteristic bands on the flagellar basal bodies. In Stage 5 sporangia, differentiation of flagella and flagellar bands was completed. Each stephanokont zoospore of D. tenuissima had about 80 flagella, about 16 nuclei and many chloroplasts.
Copyright © 2003 by Walter de Gruyter GmbH & Co. KG
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- Morphology of Prorocentrum minimum (Dinophyceae) in the Baltic Sea and in Chesapeake Bay: Comparison of Cell Shapes and Thecal Ornamentation
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Articles in the same Issue
- To Gerald T. Boalch, with Our Gratitude
- Growth and Survival of the Invasive Green Alga Codium fragile ssp. tomentosoides in Tide Pools on a Rocky Shore in Nova Scotia
- Structure of the Macroalgal Community Associated with the Seagrass Halodule wrightii Ascherson in the Abrolhos Marine National Park, Brazil
- The Life History of Lophothamnion hirtum (Hook. f. et Harv.) Womersley (Rhodophyta, Ceramiaceae) from Southern New Zealand
- Gametangium-like Structures as Propagation Buds in Codium edule Silva (Bryopsidales, Chlorophyta)
- Ultrastructural Study of Zoosporogenesis in the Siphonous Green Alga Derbesia tenuissima (Chlorophyta)
- Schimmelmannia venezuelensis sp. nov. (Gloiosiphoniaceae, Rhodophyta) from Venezuela
- Fatty Acids of Species in the Genus Codium
- Rheological Characteristics of Fucoidan Isolated from Commercially Cultured Cladosiphon okamuranus
- Effects of Light, Salinity and Inorganic Nitrogen on Cell Growth and Spirolide Production in the Marine Dinoflagellate Alexandrium ostenfeldii (Paulsen) Balech et Tangen
- Morphology of Prorocentrum minimum (Dinophyceae) in the Baltic Sea and in Chesapeake Bay: Comparison of Cell Shapes and Thecal Ornamentation
- Ordinal Placement of Selected Marine Dothideomycetes Inferred from Small Subunit Ribosomal DNA Sequence Analysis
- Meetings
