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Effects of nitrogen source and UV radiation on the growth, chlorophyll fluorescence and fatty acid composition of Phaeodactylum tricornutum and Chaetoceros muelleri (Bacillariophyceae)

Paper ID Volume ID Publish Year Pages File Format Full-Text
30872 44511 2006 12 PDF Available
Title
Effects of nitrogen source and UV radiation on the growth, chlorophyll fluorescence and fatty acid composition of Phaeodactylum tricornutum and Chaetoceros muelleri (Bacillariophyceae)
Abstract

Cultures of the marine diatoms Phaeodactylum tricornutum and Chaetoceros muelleri were grown in f/2 medium supplied with either nitrate (N-Nt), ammonium (N-Am) or urea (N-Ur) as the nitrogen (N) source at the same final N concentration (0.88 mM). Exponential growth phase cultures of the two diatoms were exposed to four different light regimes for 2 days: (UVAR) PAR (60 μmol quanta m−2 s−1) plus 8.22 W m−2 (unweighted) UVAR; (high UVBR) PAR (60 μmol quanta m−2 s−1) plus 1.04 W m−2 (unweighted) UVBR plus 13.73 W m−2 (unweighted) UVAR; (low UVBR) PAR (60 μmol quanta m−2 s−1) plus 0.19 W m−2 (unweighted) UVBR plus 2.76 W m−2 (unweighted) UVAR and (PAR) PAR (60 μmol quanta m−2 s−1) alone (control). No significant effects of N source on the growth rates of the two diatoms were detected. The maximum effective quantum yield of PSII, ΦPSIIe-max, and the initial slope of the light curve, α, of P. tricornutum and C. muelleri were all inhibited, whereas Ik was somewhat increased, as a consequence of 2 days of exposure to all the UVR treatments. Multiple factor ANOVA revealed that all the major fatty acids, both in P. tricornutum and C. muelleri, were influenced more strongly by N source than by UVR. The composition of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) in P. tricornutum and C. muelleri exhibited almost the same pattern of variation with N source and UVR. The maximum value of SFA was found in the N-Am treatment, that of MUFA in the N-Nt treatment and for PUFA in the N-Ur treatment irrespective of the UV radiation. On the other hand, the impact of UVR resulted in an increase of PUFA and a reduction of SFA both in P. tricornutum and C. muelleri under all N sources.

Keywords
Phaeodactylum tricornutum; Chaetoceros muelleri; Nitrogen source; Ultraviolet radiation; Chlorophyll fluorescence; Fatty acids
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Effects of nitrogen source and UV radiation on the growth, chlorophyll fluorescence and fatty acid composition of Phaeodactylum tricornutum and Chaetoceros muelleri (Bacillariophyceae)
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 82, Issue 3, 1 March 2006, Pages 161–172
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