Journal article


Effects of solar radiation on the Patagonian macroalga Enteromorpha linza (L.) J. Agardh - Chlorophyceae


Publication Details
Author(s): Häder DP, Lebert M, Helbling EW
Publisher: Elsevier
Publication year: 2001
Volume: 62
Journal issue: 1-2
Pages range: 43-54
ISSN: 1011-1344

Abstract

The photosynthetic performance of Enteromorpha linza (L.) J. Agardh - Chlorophyceae was determined with a portable PAM instrument in situ and under seminatural radiation conditions in Patagonia, Argentina. Solar radiation was measured in parallel with a three-channel radiometer, ELDONET (Real Time Computer, Mohrendorf, Germany), in three wavelength ranges, UV-B (280-315 nm), UV-A (315-400 nm), and PAR (400-700 nm). The effective photosynthetic quantum yield decreased after 15-min exposure to solar radiation when the thalli were kept in a fixed position but recovered in the subsequent shade conditions within several hours. A 30-min exposure of free floating thalli, however, caused less photoinhibition. The photosynthetic quantum yield of E. linza was also followed over whole days under clear sky, partly cloudy and rainy conditions in a large reservoir of water (free floating thalli) and in situ (thalli,crowing in rock pools). Most of the observed effect was due to visible radiation; however, the UV wavelength range, and especially UV-B, caused a significant reduction of the photosynthetic quantum yield. Fluence rate response curves indicated that the species is a typical shade plant which showed non-photochemical quenching at intermediate and higher irradiances. This is a surprising result since these al-ae are found in the upper eulittoral where they are exposed to high irradiances. Obviously they utilize light only during periods of low irradiances (morning, evening, high tide) while they shut down the electron transport chain during intensive exposure. Fast induction and relaxation kinetics have been measured in these algae for the first time and indicated a rapid adaptation of the photosynthetic capacity to the changing light conditions as well as a fast decrease of PS II fluorescence upon exposure to solar radiation. There was a strong bleaching of chlorophyll due to exposure to solar radiation but less drastic bleaching of carotenoids. (C) 2001 Elsevier Science B.V. All rights reserved.



How to cite
APA: Häder, D.-P., Lebert, M., & Helbling, E.W. (2001). Effects of solar radiation on the Patagonian macroalga Enteromorpha linza (L.) J. Agardh - Chlorophyceae. Journal of Photochemistry and Photobiology B-Biology, 62(1-2), 43-54. https://dx.doi.org/10.1016/S1011-1344(01)00162-2

MLA: Häder, Donat-Peter, Michael Lebert, and E. Walter Helbling. "Effects of solar radiation on the Patagonian macroalga Enteromorpha linza (L.) J. Agardh - Chlorophyceae." Journal of Photochemistry and Photobiology B-Biology 62.1-2 (2001): 43-54.

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