Repositorio
Institucional

Gomez, Ivan

Cruces, Edgardo

Huovinen, Pirjo

Interactive effects of UV radiation and enhanced temperature on photosynthesis, phlorotannin induction and antioxidant activities of two sub-Antarctic brown algae

SPRINGER HEIDELBERG

MARINE BIOLOGY

en

Lessonia nigrescens and Durvillaea antarctica, two large sub-Antarctic brown algae from the southern Chilean coast, were exposed to solar UV radiation in an outdoor system during a summer day (for 11 h) as well as to artificial UV radiation under controlled laboratory conditions at two temperatures (15 and 20 A degrees C) for 72 h. Chlorophyll a fluorescence-based photoinhibition of photosynthesis was measured during the outdoor exposure, while electron transport rates, lipid peroxidation, antioxidant activity and content of phlorotannins were determined at different time intervals during the laboratory exposure. Under natural solar irradiances in summer, both species displayed well-developed dynamic photoinhibition: F (v)/F (m) values decreased by 70 % at noon coinciding with the levels of PAR > 1,500 mu mol m(-2) s(-1) and UV-B radiation > 1 W m(-2) and recovered substantially in the afternoon. In treatments including UV radiation, recovery in D. antarctica started already during the highest irradiances at noon. The results from laboratory exposures revealed that (a) elevated temperature of 20 A degrees C exacerbated the detrimental effects of UV radiation on photochemical parameters (F (v)/F (m) and ETR); (b) peroxidative damage measured as MDA formation occurred rapidly and was strongly correlated with the decrease in F (v)/F (m), especially at elevated temperature of 20 A degrees C; (c) the antioxidant activity and increases in soluble phlorotannins were positively correlated mainly in response to UV radiation; (d) phlorotannins were rapidly induced but strongly impaired at 20 A degrees C. In general, short-term (2-6 h) exposures to enhanced UV radiation and temperature were effective to activate the photochemical and biochemical defenses against oxidative stress, and they continued operative during 72 h, a time span clearly exceeding the tidal or diurnal period. Furthermore, when algae were exposed to dim light and control temperature of 15 A degrees C for 6 h, F (v)/F (m) increased and lipid peroxidation decreased, indicating consistently that algae retained their ability for recovery. D. antarctica was the most sensitive species to elevated temperature for prolonged periods in the laboratory. Although no conclusive evidence for the effect of the buoyancy of fronds was found, the interspecific discrepancies in thermo-sensitivity in the UV responses found in this study are consistent with various ecological and biogeographical differences described for these species.

Artículo original

This study was supported by a FONDECYT grant No 1090494 to I.G. and P.H. and a CONICYT PhD fellowship No 21070148 to E.C. The authors thank the technical assistance of M. Orostegui.

Este estudio fue financiado por una beca FONDECYT n.° 1090494 otorgada a I.G. y P.H., y una beca de doctorado CONICYT n.° 21070148 otorgada a E.C. Los autores agradecen la asistencia técnica de M. Orostegui.

10.1007/s00227-012-2049-8

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CHLOROPHYLL FLUORESCENCE MEASUREMENTS

LESSONIA-NIGRESCENS LAMINARIALES

INDUCED OXIDATIVE STRESS

FILAMENTOUS GREEN-ALGAE

ULTRAVIOLET-RADIATION

MORPHOFUNCTIONAL PATTERNS

DURVILLAEA-ANTARCTICA

FUCOID ALGAE

B RADIATION

DNA-DAMAGE

CHLOROPHYLL FLUORESCENCE MEASUREMENTS

LESSONIA-NIGRESCENS LAMINARIALES

INDUCED OXIDATIVE STRESS

FILAMENTOUS GREEN-ALGAE

ULTRAVIOLET-RADIATION

MORPHOFUNCTIONAL PATTERNS

DURVILLAEA-ANTARCTICA

FUCOID ALGAE

B RADIATION

DNA-DAMAGE

Biología Marina y Limnología

Botánica

Ecología

Interactive effects of UV radiation and enhanced temperature on photosynthesis, phlorotannin induction and antioxidant activities of two sub-Antarctic brown algae

MARINE BIOLOGY

hibrida

verde

restringido

restringido

en

Artículo original

versión publicada

ANID CONICYT FONDECYT 1090494#ANID CONICYT 21070148

ANID CONICYT FONDECYT 1090494

ANID CONICYT 21070148

SPRINGER HEIDELBERG

0025-3162

1

13

Biología marina y de agua dulce

Marine & Freshwater Biology

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WOS:000313047600001