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Biological weighting functions as a tool for evaluating two ways to measure UVB radiation inhibition on photosynthesis

Paper ID Volume ID Publish Year Pages File Format Full-Text
31232 44576 2006 8 PDF Available
Title
Biological weighting functions as a tool for evaluating two ways to measure UVB radiation inhibition on photosynthesis
Abstract

To estimate the inhibitory effect of the changing UVB radiation (UVBR, 280–315 nm) on earth’s ecosystems, an understanding of its wavelength dependency is needed. The tool used for these estimations is the biological weighting function (BWF), whereby the inhibition of different wavelengths is calculated. BWFs were determined for three algae species from different classes, Phaeodactylum tricornutum (Bacillariophyceae), Dunaliella tertiolecta (Chlorophyceae) and Rhodomonas sp. (Cryptophyceae), using polychromatic irradiation, where the UVBR spectra were varied with cut-off filters. For each alga, BWFs were determined for two photosynthetic parameters; the quantum yield measured as fluorescence from Photo System II in a pulse-amplitude-modulation (PAM) fluorometer, and the fixation of 14C-labelled carbon dioxide. The BWFs were calculated with the Rundel method, using the radiation data between 270 and 360 nm with 1 nm resolution.The results show that the UVBR damages were generally higher when using the carbon fixation measurements than when measuring with the PAM technique. When using PAM, P. tricornutum in particular had a sensitivity intermediate between the sensitive Rhodomonas sp. and the more tolerant D. tertiolecta, but was as sensitive as, or even more sensitive, than Rhodomonas sp. when using carbon fixation. D. tertiolecta was shown to be less sensitive when using both techniques and the inhibition of its photosynthesis was almost as high when using PAM as when using carbon fixation.We concluded that, although the PAM technique has advantages such as being cleaner and easier to use, it is unable to substitute the carbon fixation measurements. Not only are the algae less sensitive when measured with PAM than they are when measured as carbon fixation, the relationship between the effects on the algae measured with the two techniques also differs. As fixation of carbon dioxide integrates a larger part of the photosynthetic machinery, it should be favoured as a measure of photosynthesis.

Keywords
Carbon fixation; BWF; Biological weighting function; Microalgae; PAM fluorescence; Photosynthesis inhibition; UVB
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Biological weighting functions as a tool for evaluating two ways to measure UVB radiation inhibition on photosynthesis
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 84, Issue 2, 1 August 2006, Pages 111–118
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us