Concentration Effect on Quenching of Chlorophyll a Fluorescence by All-Trans-β-Carotene in Photosynthesis

• Published in: Molecules (Basel, Switzerland) Switzerland), 2017-09, Vol.22 (10), p.1585
• Main Authors: Chen, Chen, Gong, Nan, Li, Zuowei, Sun, Chenglin, Men, Zhiwei
• Format: Article
• Language: English
• Subjects: Absorption; beta Carotene - chemistry; Blue shift; Carbon tetrachloride; Carotenoids; Chl-a; Chlorophyll; Chlorophyll - chemistry; Doppler effect; Electron transfer; Energy flow; Energy transfer; Fluorescence; Letter; Photosynthesis; Polarity; Polarizability; Quenching; Red shift; Solvents - chemistry; β-Car; β-Carotene
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules22101585

Absorption, fluorescence spectra of chlorophyll a (Chl-a) and all-trans-β-carotene (β-Car) mixing solution are investigated in different polarity and polarizability solvents. The carotenoids regulate the energy flow in photosynthesis by interaction with chlorophyll, leading to an observable reduction of Chl-a fluorescence. The fluorescence red shifts with the increasing solvent polarizability. The energy transfer in the Chl-a and β-Car system is proposed. The electron transfer should be dominant in quenching Chl-a fluorescence rather than the energy transfer in this system. Polar solvent with large polarizability shows high quenching efficiency. When dissolved in carbon tetrachloride, Chl-a presents red shift of absorption and blue shift of fluorescence spectra with increasing β-Car concentration, which implies a Chl-a conformational change.