Innate resistance of PSII efficiency to sunlight stress is not an advantage for cyanobacteria compared to eukaryotic phytoplankton
Autor: | Ralph E. H. Smith, Laura Beecraft, Susan B. Watson |
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Rok vydání: | 2019 |
Předmět: |
0106 biological sciences
Sunlight Cyanobacteria Photoinhibition biology Photosystem II Chemistry 010604 marine biology & hydrobiology Aquatic Science Photosynthetic efficiency biology.organism_classification 010603 evolutionary biology 01 natural sciences Algae Photosynthetically active radiation Phytoplankton Biophysics Ecology Evolution Behavior and Systematics |
Zdroj: | Aquatic Ecology. 53:347-364 |
ISSN: | 1573-5125 1386-2588 |
DOI: | 10.1007/s10452-019-09694-4 |
Popis: | The effects of acute solar radiation stress on photosynthetic efficiency in freshwater unialgal cultures representing three phytoplankton pigment groups were measured by pulse amplitude modulated fluorometry (Walz Phyto-PAM) and compared to previous observations on field populations. Ultraviolet radiation (UVR) (UV-B and UV-A) induced a loss of photochemical quantum efficiency (Fv/Fm) in all 13 taxa examined in culture, while effects of photosynthetically active radiation (PAR) were smaller and often insignificant. Cyanobacteria were the most sensitive to PAR and UVR stress, chlorophytes the least and chromophytes intermediate but variable. The kinetics of maximal (Fm) and minimal (F0) fluorescence responses suggested uncoupling of antenna pigments from reaction centers (decreased Fm) persistent after dark adaptation was a common response, in particular for chromophytes, while the extent of impairment from damaged reaction centers (increased F0) was more variable. Changes in Fv/Fm with irradiance exposure were well described by the Kok model of photoinhibition and indicated that damage, rather than recovery, processes were predictive of acute cumulative inhibition. Field populations of cyanobacteria and chromophytes tended to greater tolerance and lower damage rates than laboratory strains. The results for cultures under standardized conditions supported field results in showing cyanobacteria more sensitive to acute UVR exposure than eukaryotic algae, and thus lacking any innate resistance of photosystem II to sunlight stress that might help explain their success in surface bloom formation. |
Databáze: | OpenAIRE |
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