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| Format: | Artículo científico |
| Language: | en |
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Universidad Autónoma de Baja California
2002
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| Online Access: | https://www.redalyc.org/articulo.oa?id=48028301 |
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Table of Contents:
- Photoinhibition and recovery after selective short-term exposure to solar radiation of five chlorophyll c-containing marine microalgae Cristina Sobrino Griselda Parés Luis M. Lubian Olimpio Montero Ciencias de la Tierra photosynthesis photoinhibition marine microalgae ultraviolet radiation chlorophyll fluorescence The differential sensitivity of five chlorophyll c-containing marine microalgae to different components of solar radiation, e.g.photosynthetic active radiation (PAR), ultraviolet-A (UV-A) and ultraviolet-B (UV-B), was investigated in an exclusionexperiment involving exposure to PAR, PAR+UV-A and PAR+UV-A+UV-B (P-, PA- and PAB-treatment, respectively) for 20min and subsequent recovery for up to 24 h in dim light. The decrease in the variable to maximal chlorophyll fluorescence ratio(Fv/Fm) was used as indicator of photoinhibition. Changes in photosynthetic oxygen production, cell densities and pigmentcontents were also ascertained. The ratio Fv/Fm decreased in all the algae after exposure, but differences were found between thealgae and the treatments. In relation to the inhibition extent, Chaetoceros sp. was the least affected alga in each treatment, whilePhaeodactylum tricornutum was the most sensitive. Data of Fv/Fm during recovery fitted well to a sigmoid exponential function,and calculated constants were used to quantify the particular recovery rate of each alga. In general, recovery time did not show adirect relationship with the extent of inhibition. The highest recovery rate was shown by P. tricornutum cells exposed to onlyPAR, and the lowest by Isochrysis galbana cells exposed to PAB. There were no losses of cell density at the end of the recoveryperiod in relation to the initial cell density in any of the algae. Photosynthetic oxygen production dropped in the five algae in alltreatments and showed a similar evolution pattern to Fv/Fm during recovery, except for P. tricornutum and Amphidinium sp.Results of this study point out that capacity for photosynthesis inhibition is specific for each alga and, consequently, it should betaken into consideration for a reliable assessment of differential sensitivity to ultraviolet radiation among diverse marinephytoplanktonic species. 2002 artículo científico 0185-3880 https://www.redalyc.org/articulo.oa?id=48028301 en http://www.redalyc.org/revista.oa?id=480 Ciencias Marinas application/pdf Universidad Autónoma de Baja California Ciencias Marinas (México) Num.3 Vol.28