Photoacclimation Responses of the Brown Macroalga Sargassum Cymosum to the Combined Influence of UV Radiation and Salinity: Cytochemical and Ultrastructural Organization and Photosynthetic Performance. (10th January 2014)

• Record Type: Journal Article
• Authors: Polo, Luz K.; de, Marthiellen R.; Kreusch, Marianne; Pereira, Debora T.; Costa, Giulia B.; Simioni, Carmen; Ouriques, Luciane C.; Chow, Fungyi; Ramlov, Fernanda; Maraschin, Marcelo; Bouzon, Zenilda L.; Schmidt, Éder C.
• Is Part Of: Photochemistry and photobiology. Volume 90:Number 3(2014:May/Jun.)
• Page Start: 560
• Page End: 573
• Publication Date: 2014-01-10
• Subjects: Photochemistry -- Periodicals; Light -- Physiological effect -- Periodicals; 541.35
• DOI: 10.1111/php.12224
• Languages: English
• ISSNs: 0031-8655

Abstract

<abstract abstract-type="main" id="php12224-abs-0001"> <title>Abstract</title> <p>The photoacclimation responses of the brown macroalga <italic>Sargassum cymosum</italic> were studied to determine its cytochemical and ultrastructural organization, as well as photosynthetic pigments and performance. <italic>S. cymosum</italic> was cultivated in three salinities (30, 35 and 40 psu) under four irradiation treatments: PAR‐only, PAR + UVA, PAR + UVB and PAR + UVA + UVB. Plants were exposed to PAR at 70 μmol photons m⁻² s⁻¹, PAR + UVB at 0.35 W m⁻² and PAR +UVA at 0.70 W m⁻² for 3 h per day during 7 days <italic>in vitro</italic>. Growth rate was not significantly affected by any type of radiation or salinity. The amount of pigments in <italic>S. cymosum</italic> was significantly influenced by the interaction of salinity and radiation treatments. Compared with PAR‐only, UVR treatments modified the kinetics patterns of the photosynthesis/irradiance curve. After exposure to UVR, <italic> S. cymosum</italic> increased cell wall thickness and the presence of phenolic compounds. The number of mitochondria increased, whereas the number of chloroplasts showed few changes. Although <italic>S. cymosum</italic> showed insensitivity to changes in salinity, it can be concluded that samples treated under four irradiation regimes showed structural changes, which were more evident, but not severe, under PAR + UVB treatment.</p> </abstract>