Photoinhibition and UV Response in the Aquatic Environment

Häder, Donat‐P.

doi:10.1007/1-4020-3579-9_7

Cited by 5 publications

(2 citation statements)

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“…Intertidal macroalgae are exposed to dramatically changing irradiances and complex light patterns governed by the daily solar cycle, the tidal rhythm and changing cloud cover (Lu¨ning, 1990;Ha¨der, 2006). During low tide, especially when this occurs at noon on sunny days, very high irradiance is frequently associated with photoinhibition and photo-oxidative damage (Go´mez et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Carotenoid composition in Rhodophyta: insights into xanthophyll regulation inCorallina elongata

Esteban

Martínez

Fernández‐Marín

et al. 2009

European Journal of Phycology

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Macroalgae possess several photoprotection mechanisms, including xanthophyll cycles. Among these cycles, the VAZ (violaxanthin-anteraxanthin-zeaxanthin) cycle controls the interconversion of epoxidated xanthophyll (V) to de-epoxidated forms anteraxanthin and zeaxanthin. This conversion modulates the amount of excess energy that it is dissipated as heat. Presence of functional xanthophyll cycles in Rhodophyta is controversial. In this work we investigated the presence of xanthophyll cycles in red algae. Carotenoid composition of 13 red macroalgae collected in northern Spain was studied by HPLC. This screening showed that carotenoid composition is a conservative trade in rhodophytes, with very few exceptions to the general pattern formed by -carotene and one to three xanthophylls: anteraxanthin, zeaxanthin or lutein. Corallina elongata and Jania rubens were the only algae containing anteraxanthin as the main xanthophyll. The first species was selected to study whether any truncated xanthophyll cycle between anteraxanthin and zeaxanthin could operate under photoinhibitory conditions. Upon illumination, xanthophyll composition remained stable, without any short-term lightinduced de-epoxidation of anteraxanthin to zeaxanthin. However, an inverse relation between both xanthophylls was found. In addition, a seasonal trend of changes in anteraxanthin and zeaxanthin was observed when pigment composition was studied in field samples over the course of a year. We concluded that these variations were more likely due to differential rates of synthesis and degradation of xanthophylls than to the operation of a xanthophyll cycle. The great amount of anteraxanthin in C. elongata may play an structural stability role on light-harvesting complexes.

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Section: Introductionmentioning

confidence: 99%

Carotenoid composition in Rhodophyta: insights into xanthophyll regulation inCorallina elongata

Esteban

Martínez

Fernández‐Marín

et al. 2009

European Journal of Phycology

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“…In the case of abrupt changes in environmental conditions during emersion, algae can respond through photochemical downregulation ( e.g. dynamic photoinhibition), which serves to dissipate excess energy (12–14) and complementarily, by activating the whole suite of radical scavenging mechanisms, e.g. antioxidative enzymes (7,8).…”

Section: Introductionmentioning

confidence: 99%

Phlorotannin and Antioxidant Responses Upon Short‐term Exposure to UV Radiation and Elevated Temperature in Three South Pacific Kelps

Cruces

Huovinen

Gómez

2011

Photochem & Photobiology

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Rapid adjustments of the photosynthetic machinery and efficient antioxidant mechanisms to scavenge harmful ROS are physiologic adaptions exhibited by intertidal seaweeds to persist in temperate regions. This study examines short-term (3 h) responses of three large kelps from the cold-temperate coast of Chile, normally adapted to water temperatures <16°C, but exposed abruptly to simultaneous high temperatures and UV radiation during low tide in summer. The kelps were exposed in the laboratory to three temperatures (10, 20 and 28°C) with and without UV radiation, and photochemical reactions, concentration of phlorotannins and antioxidant activity were examined. The exposure to elevated temperature (slightly exacerbated by the presence of UV radiation) decreased photochemical processes (measured as fluorescence kinetics) in the three studied species and increased lipid peroxidation in two of them. The concentration of total soluble phlorotannins was variable and correlated with the antioxidant activity in the presence of UV radiation. Insoluble phlorotannins did not change during the exposure. In all, the downregulation of the photochemical machinery, which was expressed as dynamic photoinhibition, and the rapid induction of soluble phlorotannins triggered by UV radiation minimized the effects of oxidative stress and maintained the operation of photochemical processes during short-term thermal stress.

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