XXXIV 



CHLOROPHYLL AND CHLOROPHYLL DEVELOPMENT 

 IN RELATION TO RADIATION 



0. L. Inman, Paul Rothemund, and C. F. Kettering 



Antioch College, Y^ellow Springs, Ohio 



Condition of chlorophyll in the chloroplast. Chlorophyll developinent in relation to 

 radiation. Effect of radiation on extracted chlorophyll. Behavior of chlorophyll under 

 the influence of tdtra-violet radiation. Influence of factors other than radiation on 

 chlorophyll formation. Yellow pigments associated with chlorophyll. References. 



CONDITION OF CHLOROPHYLL IN THE CHLOROPLAST 



A good review of the literature on the origin of plastids in the plant 

 and on the association of the various pigments in the same plastid was 

 given by Zimmermann (89). Pfeffer (54) called attention to the fact 

 that since the plastid is an organized part of the living cell, its functioning 

 must at all times be considered with this in mind. Willstatter and Stoll 

 (86, pages 54-55) believed chlorophyll to be held in the chloroplast in the 

 colloidal state. The action of solvents upon the leaf material, and the 

 nature of the absorption spectrum of the living leaf as compared with that 

 of extracted chlorophyll which had been made colloidal, led to this 

 opinion. 



Stern (72) concluded that only molecularly dispersed chlorophyll is 

 fluorescent and, since chlorophyll in the chloroplast, as in the alga 

 Chlorella, is fluorescent, it is therefore molecularly dispersed through the 

 plastid and may be in a viscous solvent (hpoid) which is itself coUoidally 

 dispersed. Tswett (78a) demonstrated that chlorophyll fluoresces in the 

 living plant and he found fluorescence in Spirogyra at X6850 to 6700 A 

 and X6600 to 6500 A, and in Oscillaloria at X6700 to 6300 A. Lloyd (37) 

 confirmed these results of Tswett. According to Noack (46) chlorophyll 

 in the living leaf is present in a state of adsorption in a monomolecular 

 layer on the protein of the chloroplasts. Hilpert, Hofmeier, and Wolter 

 (27) believe that the chlorophyll in the leaf is related in some way both 

 to the carotinoids and to protein, and that it is certainly not in solution 

 in the lipoid phase. It is obvious that there still remains room for 

 further clarification as to the physicochemical state of the chlorophyll 

 in the chromatophore. 



CHLOROPHYLL DEVELOPMENT IN RELATION TO RADIATION 



In general, plants do not become green unless exposed to visible 

 radiation, but Artari (1) showed that some one-celled algae turn green 



1093 



