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Response of Growth and Photosynthesis of Emiliania huxleyi to Visible and UV Irradiances under Different Light Regimes
Author(s) -
Xing Tao,
Gao Kunshan,
Beardall John
Publication year - 2015
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.12403
Subject(s) - emiliania huxleyi , photosynthesis , coccolithophore , growth rate , photosystem ii , sunlight , biology , ultraviolet , botany , phytoplankton , nutrient , ecology , physics , optics , geometry , mathematics
Microalgae are capable of acclimating to changes in light and ultraviolet radiation ( UVR , 280–400 nm). However, little is known about how the ecologically important coccolithophore Emiliania huxleyi responds to UVR when acclimated to different light regimes. Here, we grew E. huxleyi under indoor constant light or fluctuating sunlight with or without UVR , and investigated its growth, photosynthetic performance and pigmentation. Under the indoor constant light regime, the specific growth rate ( μ ) was highest, while fluctuating outdoor solar radiation significantly decreased the growth rate. Addition of UVR further decreased the growth rate. The repair rate of photosystem II ( PSII ), as reflected in changes in PSII quantum yield, showed an inverse correlation with growth rate. Cells grown under the indoor constant light regime exhibited the lowest repair rate, while cells from the outdoor fluctuating light regimes significantly increased their repair rate. Addition of UVR increased both the repair rate and intracellular UV ‐absorbing compounds. This increased repair capability, at the cost of decreased growth rate, persisted after the cells were transferred back to the indoor again, suggesting an enhanced allocation of energy and resources for repair of photosynthetic machinery damage by solar UVR which persisted for a period after transfer from solar UVR .