title: Ultrastructural changes accompanying mitosporogenesis in Ectocarpus parvus.
abstract: The plurilocular zoosporangium of Ectocarpus parvus Saunders in initiated as a uniseriate branch from a vegetative cell. Subsequent anticlinal and periclinal divisions of the cells leads to enlargement of the sporangium and the formation of multiple locules. Each locule containes a single biflagellate zoospore. Ultrastructural changes accompanying these events include a reduction in the size of chromatophores, a reduction in the number of dictyosomes and the appearance of plasmalemmasomes in later stages. Enlargement of the mitochondria and a decrease in size of the nucleus occur in the final stages of zoospore formation. Comparison with the vegetative and sporogenous cells of other brown algae are made.
mesh_terms: D002455:Cell Division; D002467:Cell Nucleus / Q000648:ultrastructure; D002856:Chromatophores / Q000648:ultrastructure; D004721:Endoplasmic Reticulum / Q000648:ultrastructure; D056890:Eukaryota / Q000648:ultrastructure*; D002479:Inclusion Bodies / Q000648:ultrastructure; D008928:Mitochondria / Q000648:ultrastructure; D009940:Organoids / Q000648:ultrastructure; D000459:Phaeophyceae / Q000254:growth & development / Q000648:ultrastructure*; D013170:Spores / Q000254:growth & development* / Q000648:ultrastructure