Photosynthetic responses to UV-radiation of intertidal macroalgae from the Strait of Magellan (Chile)

For the first time, the photosynthetic performance of field-grown macroalgae from the Magellan Strait was evaluated with respect to their photoadaptation in the field and acclimation potential to ultraviolet radiation. Five macroalgal species were collected in the eulittoral and the upper sublittora...

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Autores principales:	RAUTENBERGER,RALF, MANSILLA,ANDRÉS, GÓMEZ,IVÁN, WIENCKE,CHRISTIAN, BISCHOF,KAI
Lenguaje:	English
Publicado:	Sociedad de Biología de Chile 2009
Materias:	UV-radiation macroalgae photosynthesis photoacclimation Strait of Magellan
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2009000100003
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spelling	oai:scielo:S0716-078X20090001000032009-07-29Photosynthetic responses to UV-radiation of intertidal macroalgae from the Strait of Magellan (Chile)RAUTENBERGER,RALFMANSILLA,ANDRÉSGÓMEZ,IVÁNWIENCKE,CHRISTIANBISCHOF,KAI UV-radiation macroalgae photosynthesis photoacclimation Strait of Magellan For the first time, the photosynthetic performance of field-grown macroalgae from the Magellan Strait was evaluated with respect to their photoadaptation in the field and acclimation potential to ultraviolet radiation. Five macroalgal species were collected in the eulittoral and the upper sublittoral: Ulva intestinalis, Porphyra columbina, Adenocystis utricularis, Desmarestia confervoides and D. ligulata. Photosynthesis vs. irradiance (P-I) curves of macroalgae cultivated in the laboratory under low white light intensities more than a week were used to assess the acclimation potential to irradiance conditions in the field. Both, photosynthetic parameters referred to as maximum electron transport rate (ETRmax) and light saturation points of photosynthesis (Ik) were species-specific and did not correlate with the position on the shore. Ik ranging between 80 and 215 μmol photons m-2 s-1 was indicative of moderate sun-adaptation in all studied species. The acclimation potential to UV-radiation was determined as the extent and the rates (m inh) of PSII inhibition (resulting from decreased maximum PSII-quantum yield (Fv/Fm)) after four hours of UV-exposure and as the subsequent rates of recovery (m ) in dim PAR. The results suggest that photosynthesis of each species during UV-exposure was transiently down regulated rather than damaged. Furthermore, no reductions in ETRmax were detected after 4 h exposure to UV-A and UV-B-radiation, and consequently the Calvin cycle could not be affected. Thus, Fv/Fm was a more sensitive parameter than ETRmax explaining the photosynthetic UV acclimation. Both, the rates of inhibition and the rates of recovery were not correlated with the morpho-functional groups of macroalgae nor to their vertical distribution. Thus, although the capacity to acclimate to UV-radiation varied among the different species, data suggest that such responses are based on metabolic adjustments or possibly photoprotective strategies. In conclusion and taking into account the light adaptation characteristics, all species collected in the midlittoral and the upper sublittoral at the Strait of Magellan seem to be well acclimated to UV-B doses occurring at their habitat, which might be a pre-requisite to withstand enhanced solar UV-B during ozone depletion or summertime irradiance conditions.info:eu-repo/semantics/openAccessSociedad de Biología de ChileRevista chilena de historia natural v.82 n.1 20092009-03-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2009000100003en10.4067/S0716-078X2009000100003
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	UV-radiation macroalgae photosynthesis photoacclimation Strait of Magellan
spellingShingle	UV-radiation macroalgae photosynthesis photoacclimation Strait of Magellan RAUTENBERGER,RALF MANSILLA,ANDRÉS GÓMEZ,IVÁN WIENCKE,CHRISTIAN BISCHOF,KAI Photosynthetic responses to UV-radiation of intertidal macroalgae from the Strait of Magellan (Chile)
description	For the first time, the photosynthetic performance of field-grown macroalgae from the Magellan Strait was evaluated with respect to their photoadaptation in the field and acclimation potential to ultraviolet radiation. Five macroalgal species were collected in the eulittoral and the upper sublittoral: Ulva intestinalis, Porphyra columbina, Adenocystis utricularis, Desmarestia confervoides and D. ligulata. Photosynthesis vs. irradiance (P-I) curves of macroalgae cultivated in the laboratory under low white light intensities more than a week were used to assess the acclimation potential to irradiance conditions in the field. Both, photosynthetic parameters referred to as maximum electron transport rate (ETRmax) and light saturation points of photosynthesis (Ik) were species-specific and did not correlate with the position on the shore. Ik ranging between 80 and 215 μmol photons m-2 s-1 was indicative of moderate sun-adaptation in all studied species. The acclimation potential to UV-radiation was determined as the extent and the rates (m inh) of PSII inhibition (resulting from decreased maximum PSII-quantum yield (Fv/Fm)) after four hours of UV-exposure and as the subsequent rates of recovery (m ) in dim PAR. The results suggest that photosynthesis of each species during UV-exposure was transiently down regulated rather than damaged. Furthermore, no reductions in ETRmax were detected after 4 h exposure to UV-A and UV-B-radiation, and consequently the Calvin cycle could not be affected. Thus, Fv/Fm was a more sensitive parameter than ETRmax explaining the photosynthetic UV acclimation. Both, the rates of inhibition and the rates of recovery were not correlated with the morpho-functional groups of macroalgae nor to their vertical distribution. Thus, although the capacity to acclimate to UV-radiation varied among the different species, data suggest that such responses are based on metabolic adjustments or possibly photoprotective strategies. In conclusion and taking into account the light adaptation characteristics, all species collected in the midlittoral and the upper sublittoral at the Strait of Magellan seem to be well acclimated to UV-B doses occurring at their habitat, which might be a pre-requisite to withstand enhanced solar UV-B during ozone depletion or summertime irradiance conditions.
author	RAUTENBERGER,RALF MANSILLA,ANDRÉS GÓMEZ,IVÁN WIENCKE,CHRISTIAN BISCHOF,KAI
author_facet	RAUTENBERGER,RALF MANSILLA,ANDRÉS GÓMEZ,IVÁN WIENCKE,CHRISTIAN BISCHOF,KAI
author_sort	RAUTENBERGER,RALF
title	Photosynthetic responses to UV-radiation of intertidal macroalgae from the Strait of Magellan (Chile)
title_short	Photosynthetic responses to UV-radiation of intertidal macroalgae from the Strait of Magellan (Chile)
title_full	Photosynthetic responses to UV-radiation of intertidal macroalgae from the Strait of Magellan (Chile)
title_fullStr	Photosynthetic responses to UV-radiation of intertidal macroalgae from the Strait of Magellan (Chile)
title_full_unstemmed	Photosynthetic responses to UV-radiation of intertidal macroalgae from the Strait of Magellan (Chile)
title_sort	photosynthetic responses to uv-radiation of intertidal macroalgae from the strait of magellan (chile)
publisher	Sociedad de Biología de Chile
publishDate	2009
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2009000100003
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Photosynthetic responses to UV-radiation of intertidal macroalgae from the Strait of Magellan (Chile)

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