title: Effects of natural radiation, photosynthetically active radiation and artificial ultraviolet radiation-B on the chloroplast organization and metabolism of Porphyra acanthophora var. brasiliensis (Rhodophyta, Bangiales).
abstract: We undertook a study of Porphyra acanthophora var. brasiliensis to determine its responses under ambient conditions, photosynthetically active radiation (PAR), and PAR+UVBR (ultraviolet radiation-B) treatment, focusing on changes in ultrastructure, and cytochemistry. Accordingly, control ambient samples were collected in the field, and two different treatments were performed in the laboratory. Plants were exposed to PAR at 60 μmol photons m-2 s-1 and PAR + UVBR at 0.35 W m-2 for 3 h per day during 21 days of in vitro cultivation. Confocal laser scanning microscopy analysis of the vegetative cells showed single stellate chloroplast in ambient and PAR samples, but in PAR+UVBR-exposed plants, the chloroplast showed alterations in the number and form of arms. Under PAR+UVBR treatment, the thylakoids of the chloroplasts were disrupted, and an increase in the number of plastoglobuli was observed, in addition to mitochondria, which appeared with irregular, disrupted morphology compared to ambient and PAR samples. After UVBR exposure, the formation of carpospores was also observed. Plants under ambient conditions, as well as those treated with PAR and PAR+UVBR, all showed different concentrations of enzymatic response, including glutathione peroxidase and reductase activity. In summary, the present study demonstrates that P. acanthophora var. brasiliensis shows the activation of distinct mechanisms against natural radiation, PAR and PAR+UVBR.
authors.affiliation: Central Laboratory of Electron Microscopy, Federal University of Santa Catarina              88049-900, CP 476, Florianópolis, SC, Brazil.
authors.forename: Zenilda L
authors.initials: ZL
authors.lastname: Bouzon
authors.forename: Fungyi
authors.initials: F
authors.lastname: Chow
authors.forename: Carmen S
authors.initials: CS
authors.lastname: Zitta
authors.forename: Rodrigo W
authors.initials: RW
authors.lastname: dos Santos
authors.forename: Luciane C
authors.initials: LC
authors.lastname: Ouriques
authors.forename: Marthiellen R de L
authors.initials: MR
authors.lastname: Felix
authors.forename: Luz K P
authors.initials: LK
authors.lastname: Osorio
authors.forename: Claudiane
authors.initials: C
authors.lastname: Gouveia
authors.forename: Roberta de Paula
authors.initials: Rde P
authors.lastname: Martins
authors.forename: Alexandra
authors.initials: A
authors.lastname: Latini
authors.forename: Fernanda
authors.initials: F
authors.lastname: Ramlov
authors.forename: Marcelo
authors.initials: M
authors.lastname: Maraschin
authors.forename: Eder C
authors.initials: EC
authors.lastname: Schmidt
mesh_terms: D002338:Carotenoids / Q000032:analysis; D048430:Cell Shape / Q000528:radiation effects; D002473:Cell Wall / Q000378:metabolism; D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D002736:Chloroplasts / Q000378:metabolism* / Q000528:radiation effects*; D003593:Cytoplasm / Q000378:metabolism; D004789:Enzyme Activation; D057075:Enzyme Assays; D005979:Glutathione Peroxidase / Q000378:metabolism; D018613:Microscopy, Confocal / Q000379:methods; D008928:Mitochondria / Q000378:metabolism / Q000528:radiation effects; D009245:NADH Dehydrogenase; D053140:Organelle Shape / Q000528:radiation effects; D017785:Photons; D010788:Photosynthesis; D059828:Plant Cells / Q000378:metabolism; D044664:Porphyra / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism* / Q000528:radiation effects*; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D002734:Chlorophyll; D002338:Carotenoids; D005979:Glutathione Peroxidase; D009245:NADH Dehydrogenase; D000077194:Chlorophyll A