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CHLOROPHYLL a FLUORESCENCE YIELD IN LIVE CELLS AND SOLUTIONS
Author(s) -
Murty N. R.,
Cederstrand C. N.,
Rabinowitch E.
Publication year - 1965
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/j.1751-1097.1965.tb07940.x
Subject(s) - fluorescence , quantum yield , chlorella pyrenoidosa , photochemistry , chlorophyll , yield (engineering) , quenching (fluorescence) , chlorophyll fluorescence , excited state , methanol , chemistry , chlorophyll a , ether , absorption (acoustics) , analytical chemistry (journal) , chlorella , botany , chromatography , materials science , biology , biochemistry , organic chemistry , optics , algae , physics , atomic physics , metallurgy , composite material
— Fluorescence yields of chlorophyll a in ether and methanol solutions ( F s ), on the one hand, and in Chlorella pyrenoidosa and Anacystis nidulans cells (F c ), on the other hand, were determined by excitation at 600 mμ (instead of at 436 mμ, as was done in earlier research in our, and other, laboratories). The ratio of the yields Fs/F c , was found to be 5.9 for Chlorella (compared to an ether solution of chlorophyll a ), and of 4.5 (as compared to a methanol solution—not too different from the corresponding ratios of fluorescence lifetimes, τ s /τ c which were determined earlier as 3.1 and 4, respectively. The much higher values of the yield ratio, previously reported for Chlorella (about 13, compared to chlorophyll a in ether solution), may have been due to disregard of light absorption in carotenoids in live cells; and perhaps also to quenching of chlorophyll excitation by carotenoids. The latter can occur (as suggested in an earlier publication) when chlorophyll is excited to its second singlet excited state. For Anacystis , the yield ratios were now found to be 5.1 and 3.8, when compared to ether and methanol solutions respectively; while the previously determined lifetime ratios were 3.7 and 4.9, respectively. It remains to be seen whether the remaining differences between the lifetime ratios and the yield ratios are real and significant.