356 



David C. Fork 



showed peaks at 470 (chlorophyll c) and at 540 inp (fucoxanthin) 

 and minor peaks at 610 and 660 mp. 



c 

 o 



<J 



3 



o 



o 



c 



0) 



u 



1. 



a 



Wavelength, my 



Fig. 4, Action spectra for O2 production in Drouetia 

 rotata (10°C) with and without green (546 mn) backgrovind 

 light. Fork(7). 



c 

 o 



-T 1 1 1 1 



Ulva 

 ~485 ~645 



p o-°~o' 



801 



400 



o o 



c 



0) 



<J 



Q.I80h 



c 



0) 



6 



0) 



o 



o 140 



~B 



"T 1 1 1 1 r 



Endarachne binghamiae 



540 

 470 ^'i, V 



A 1 A < 



,^ A- tfA 



^AAAA-^.,^ 

 ^ A°A V 



'^A 



500 600 700 



Wavelength, mp 



100 

 400 



^•aA 



500 600 700 



Wavelength, m/j 



Fig. 5. Action spectra for enhancement in Ulva and 

 Endarachne binghamiae with a background light of wave- 

 lengths longer than 680 mp. Fork('^. 



EVIDENCE FOR TWO LIGHT REACTIONS IN CHLOROPLASTS 



If a two-pigment mechanism functions in photosynthesis, one 

 would expect to be able to observe the enhancement effect in 



