title: Influences of cadmium on fine structure and metabolism of Hypnea musciformis (Rhodophyta, Gigartinales) cultivated in vitro.
abstract: The in vitro effect of cadmium on apical segments of Hypnea musciformis was examined. Over a period of 7 days, the segments were cultivated with different concentrations of cadmium, ranging from 50 to 300 μM. The samples were processed for microscopic and histochemical analysis of growth rates, content of photosynthetic pigments, and photosynthetic performance. Cadmium treatments increased cell wall thickness and the accumulation of plastoglobuli. Destruction of chloroplast internal organization was observed. Compared to controls, algae exposed to cadmium showed growth rate reduction, depigmentation, and blending in the lateral branches. The content of photosynthetic pigments, including chlorophyll a and phycobiliproteins, decreased after exposure to different concentrations of cadmium. These results agree with the decreased photosynthetic performance and relative electron transport rate observed after exposure of algae to cadmium. Taken together, these findings strongly indicate that cadmium negatively affects the architecture and metabolism of the carragenophyte H. musciformis, thus posing a threat to the economic vitality of this red macroalgae.
authors: Central Laboratory of Electron Microscopy, Federal University of Santa Catarina, 88049-900, CP 476, Florianópolis, SC, Brazil.
authors: Zenilda L
authors: ZL
authors: Bouzon
authors: Eduardo C
authors: EC
authors: Ferreira
authors: Rodrigo
authors: R
authors: dos Santos
authors: Fernando
authors: F
authors: Scherner
authors: Paulo A
authors: PA
authors: Horta
authors: Marcelo
authors: M
authors: Maraschin
authors: Eder C
authors: EC
authors: Schmidt
mesh_terms: D002104:Cadmium / Q000494:pharmacology*; D002473:Cell Wall / Q000187:drug effects / Q000648:ultrastructure; D002736:Chloroplasts / Q000187:drug effects / Q000648:ultrastructure; D010788:Photosynthesis / Q000187:drug effects; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism; D000461:Rhodophyta / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D013499:Surface Properties / Q000187:drug effects; D014617:Vacuoles / Q000187:drug effects / Q000648:ultrastructure; D014874:Water Pollutants, Chemical / Q000494:pharmacology*
chemical_list: D045322:Photosynthetic Reaction Center Complex Proteins; D014874:Water Pollutants, Chemical; D002104:Cadmium