Effects of solar UV radiation on photosynthesis and enzyme activities (carbonic anhydrase and nitrate reductase) in marine macroalgae from southern Spain

The effects of solar ultraviolet (UV) radiation during daily cycles on photosynthesis and two key enzymes involved in carbon incorporation, the carbonic anhydrase, and in inorganic nitrogen reduction, the nitrate reductase, of macroalgae from southern Spain are presented. During daily cycles, photoi...

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Autores principales:	FIGUEROA,FÉLIX L., VIÑEGLA,BENJAMÍN
Lenguaje:	English
Publicado:	Sociedad de Biología de Chile 2001
Materias:	carbonic anhydrase chlorophyll fluorescence effective quantum yield nitrate reductase ultraviolet radiation
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2001000200003
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spelling	oai:scielo:S0716-078X20010002000032001-11-08Effects of solar UV radiation on photosynthesis and enzyme activities (carbonic anhydrase and nitrate reductase) in marine macroalgae from southern SpainFIGUEROA,FÉLIX L.VIÑEGLA,BENJAMÍN carbonic anhydrase chlorophyll fluorescence effective quantum yield nitrate reductase ultraviolet radiation The effects of solar ultraviolet (UV) radiation during daily cycles on photosynthesis and two key enzymes involved in carbon incorporation, the carbonic anhydrase, and in inorganic nitrogen reduction, the nitrate reductase, of macroalgae from southern Spain are presented. During daily cycles, photoinhibition in several intertidal macroalgae, expressed as decrease in the effective quantum yield from the morning to noon time, was linearly dependent on the daily integrated irradiance. However, recovery, expressed as the increase in the effective quantum yield from noon to the afternoon, presented a different pattern; full recovery was found below daily integrated irradiance of 1.0 x10(4) kJ m-2. However, recovery reached only 50 % at higher irradiances. The existence of daily photoinhibition and full recovery in intertidal algae suggests that photoinhibition is a photoprotective mechanism against high solar radiation as in higher plants, and that patterns of photoinhibition and recovery are affected by accumulative doses. Activities of carbonic anhidrase and nitrate reductase were determined in three marine macroalgae (Plocamium cartilagineum, Ulva rigida and Fucus spiralis) under full (PAR + UV-A + UV-B) and excluded UV solar radiation (PAR). Under PAR + UV-A + UV-B, peaks of enzyme activity were found in P. cartilagineum during the evening, and accordingly to data previously published for other red macroalgae. This situation was modified by the absence of UV radiation since the increase in the activities was delayed several hours. In the three macroalgae and under full solar radiation, a significant and negative correlation was found only when data from nitrate reductase activity was shifted in time during at least four hours. This correlation is lost in Ulva rigida when UV radiation is excluded. The existence of these daily variations with a negative correlation of both enzyme activities could reflect a complex regulatory link between carbon and nitrogen metabolism under solar radiation. Considering the absence of a significant correlation in U. rigida and the delay observed in maximal activities of P. cartilagineum in the absence of UV, it is suggested that UV radiation acts as an environmental signal involved in the control of cycles. The presence of feedback processes that control nitrogen assimilation as a function of carbon content is proposedinfo:eu-repo/semantics/openAccessSociedad de Biología de ChileRevista chilena de historia natural v.74 n.2 20012001-06-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2001000200003en10.4067/S0716-078X2001000200003
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	carbonic anhydrase chlorophyll fluorescence effective quantum yield nitrate reductase ultraviolet radiation
spellingShingle	carbonic anhydrase chlorophyll fluorescence effective quantum yield nitrate reductase ultraviolet radiation FIGUEROA,FÉLIX L. VIÑEGLA,BENJAMÍN Effects of solar UV radiation on photosynthesis and enzyme activities (carbonic anhydrase and nitrate reductase) in marine macroalgae from southern Spain
description	The effects of solar ultraviolet (UV) radiation during daily cycles on photosynthesis and two key enzymes involved in carbon incorporation, the carbonic anhydrase, and in inorganic nitrogen reduction, the nitrate reductase, of macroalgae from southern Spain are presented. During daily cycles, photoinhibition in several intertidal macroalgae, expressed as decrease in the effective quantum yield from the morning to noon time, was linearly dependent on the daily integrated irradiance. However, recovery, expressed as the increase in the effective quantum yield from noon to the afternoon, presented a different pattern; full recovery was found below daily integrated irradiance of 1.0 x10(4) kJ m-2. However, recovery reached only 50 % at higher irradiances. The existence of daily photoinhibition and full recovery in intertidal algae suggests that photoinhibition is a photoprotective mechanism against high solar radiation as in higher plants, and that patterns of photoinhibition and recovery are affected by accumulative doses. Activities of carbonic anhidrase and nitrate reductase were determined in three marine macroalgae (Plocamium cartilagineum, Ulva rigida and Fucus spiralis) under full (PAR + UV-A + UV-B) and excluded UV solar radiation (PAR). Under PAR + UV-A + UV-B, peaks of enzyme activity were found in P. cartilagineum during the evening, and accordingly to data previously published for other red macroalgae. This situation was modified by the absence of UV radiation since the increase in the activities was delayed several hours. In the three macroalgae and under full solar radiation, a significant and negative correlation was found only when data from nitrate reductase activity was shifted in time during at least four hours. This correlation is lost in Ulva rigida when UV radiation is excluded. The existence of these daily variations with a negative correlation of both enzyme activities could reflect a complex regulatory link between carbon and nitrogen metabolism under solar radiation. Considering the absence of a significant correlation in U. rigida and the delay observed in maximal activities of P. cartilagineum in the absence of UV, it is suggested that UV radiation acts as an environmental signal involved in the control of cycles. The presence of feedback processes that control nitrogen assimilation as a function of carbon content is proposed
author	FIGUEROA,FÉLIX L. VIÑEGLA,BENJAMÍN
author_facet	FIGUEROA,FÉLIX L. VIÑEGLA,BENJAMÍN
author_sort	FIGUEROA,FÉLIX L.
title	Effects of solar UV radiation on photosynthesis and enzyme activities (carbonic anhydrase and nitrate reductase) in marine macroalgae from southern Spain
title_short	Effects of solar UV radiation on photosynthesis and enzyme activities (carbonic anhydrase and nitrate reductase) in marine macroalgae from southern Spain
title_full	Effects of solar UV radiation on photosynthesis and enzyme activities (carbonic anhydrase and nitrate reductase) in marine macroalgae from southern Spain
title_fullStr	Effects of solar UV radiation on photosynthesis and enzyme activities (carbonic anhydrase and nitrate reductase) in marine macroalgae from southern Spain
title_full_unstemmed	Effects of solar UV radiation on photosynthesis and enzyme activities (carbonic anhydrase and nitrate reductase) in marine macroalgae from southern Spain
title_sort	effects of solar uv radiation on photosynthesis and enzyme activities (carbonic anhydrase and nitrate reductase) in marine macroalgae from southern spain
publisher	Sociedad de Biología de Chile
publishDate	2001
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2001000200003
work_keys_str_mv	AT figueroafelixl effectsofsolaruvradiationonphotosynthesisandenzymeactivitiescarbonicanhydraseandnitratereductaseinmarinemacroalgaefromsouthernspain AT vineglabenjamin effectsofsolaruvradiationonphotosynthesisandenzymeactivitiescarbonicanhydraseandnitratereductaseinmarinemacroalgaefromsouthernspain
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Effects of solar UV radiation on photosynthesis and enzyme activities (carbonic anhydrase and nitrate reductase) in marine macroalgae from southern Spain

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