535 



John A. Bergeron 



10 



|nit|rrTi[Mii|iiti|tiit|tMi|irii|iiii|iii[|UII|liii|iiii|Mn|iiM|llll|llll|l1M|llll|IIIL 



9l( DILUTE SUSPENSION) A, ANACYSTIS FLUORESCENCE 



Sr ; \ 578 m^ EXCITATION - 



7 1- /'\ I \ 22 °C 



O 



" 5 



/ 



\ / y.., \ 22°C 



>.„/ .'V/--^' Vy-|96°C- 



-ise-c 



436m^ EXCITATION 



rTiTl 1 1 L 1 1 1 1 1 1 1 11 1 1 1 1 1 11 1 1 1 u 1 1 11 1 1 1 II 1 1 1 1 1 1 1 nil 1 1 II 1 1 1 1 III I II I li I 

 620 640 660 680 700 720 740 760 780 

 X m ^ 



Fig. 8. Effect of temperature on the fluorescence of 

 Anacystis * Two new bands appear at -196° C, one at 

 700 mn, the other at 720 m\i, 



energy sinks which straddle the red absorption maximum of the 

 bulk of the chlorophyll £ it is possible to explain the energy 

 flow between the two light reactions of higher plant photosynthe- 

 sis by means of sensitized fluorescence. Presumably the phyco- 

 cyanin and phycoerythrin of blue-green and red algae and the 

 chlorophyll b of higher plants fill the role of funneling energy 

 into the energy acceptor of system two. 



ACKNOWLEDGEMENTS 



Research carried out at Brookhaven National Laboratory under 

 the auspices of the U. S. Atomic Energy Commission. The author 

 wishes to thank Miss E. Stanton and Mr. W. Geisbusch for techni- 

 cal assistance, 



REFERENCES 



Dougherty, E.C. & Allen, M.B., in Comparative Biochemistry of 

 Photoreactive Systems (Allen, M.B., ed.) Academic Press, N.y!, 

 i960, pp. 129-lUi^. 



2 Amesz, J. & Duysens, L.N.M., Biochim. Biophys. Acta 6U, 261-278 

 (1962). ^ 



■J Duysens, L.N.M., Transfer of Excitation Energy in Photosynthe - 

 sis , Ph.D. Thesis, Univ. Utrecht, 1952. 



