| Molecular iodine emission rates and photosynthetic performance of different thallus parts of Laminaria digitata (Phaeophyceae) during emersion. | |
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MedLine Citation:
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PMID: 21188416 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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The emission of molecular iodine (I(2)) from the stipe, the meristematic area and the distal blade of the brown macroalga Laminaria digitata (Hudson) Lamouroux (Phaeophyceae) was monitored under low light and dark conditions. Photosynthetic parameters were determined to investigate both the extent of stress experienced by different thallus parts and the effects of emersion on photosynthesis. Immediately after air exposure, intense I(2) emission was detectable from all thallus parts. I(2) emission declined continuously over a period of 180 min following the initial burst, but was not affected by the light regime. The total number of mole of I(2) emitted by stipes was approximately 10 times higher than those emitted from other thallus parts. Initial I(2) emission rates (measured within 30 min of exposure to air) were highest for stipes (median values: 2,999 and 5,222 pmol g(-1) dw min(-1) in low light and dark, respectively) and lower, by one order of magnitude, for meristematic regions and distal blades. After exposure to air for between 60 and 180 min, I(2) emission rates of all thallus parts were reduced by 70-80%. Air exposure resulted in a decrease of the maximum photosystem II (PSII) efficiency (F (v)/F (m)) by 3%, and in a 25-55% increase of the effective PSII quantum efficiency ([Formula: see text]); this was caused by a higher fraction of open reaction centres (q(P)), whereas the efficiency of the latter in capturing energy ([Formula: see text]) remained constant. The results indicate the presence of an iodine pool which is easily volatilised and depleted due to air exposure, even under apparently low stress conditions. |
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Authors:
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Udo Nitschke; Albert A Ruth; Sophie Dixneuf; Dagmar B Stengel |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2010-12-28 |
Journal Detail:
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Title: Planta Volume: - ISSN: 1432-2048 ISO Abbreviation: - Publication Date: 2010 Dec |
Date Detail:
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Created Date: 2010-12-28 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 1250576 Medline TA: Planta Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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Botany and Plant Science, School of Natural Sciences, Ryan Institute for Environmental, Marine and Energy Research, National University of Ireland Galway, Galway, Ireland. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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