PROTEIN FORMATION IN DARKNESS 57 



supply of carbohydrate be at hand.* Zaleski and Suzuki f 

 found that the leaves of the sunflower floating upon a solution 

 containing sugar and nitrate produced considerable quantities of 

 proteins in the dark, from which it appears that nitrogen as- 

 similation is not a photochemical process, and that light is only 

 of indirect importance in providing one of the means for the 

 formation of carbohydrates. J This opinion also is held by 

 Loew. 



The synthesis of proteins is conditioned by the available 

 supply of carbohydrate, and since photosynthesis is a daylight 

 process, it is not surprising to find that the production of pro- 

 teins may be four or five times as great in the light as in 

 darkness.!! BaudischlF is of the opinion that the formation of 

 protein under abnormal conditions in the dark is no proof 

 that the process is not a photochemical one under normal con- 

 ditions ; he considers that the synthesis may in this case be 

 due to some abnormal chemical processes which reduce the 

 nitrates and so aid in the production of proteins. It has also 

 been stated that if but small quantities of carbohydrate are 

 available, the synthesis of proteins, in darkness, may stop at 

 the formation of amides,** which some plants, e.g., Algae such 

 as Pleurococcus and Raphidium> and the Fungi Eurotium and 

 Penicillium, can directly assimilate,ff an aspect of the subject 

 to which allusion has already been made. 



There is available but little exact knowledge regarding the 

 specific action of different wave lengths of radiant energy 

 which may be concerned in the different phases of protein 

 metabolism. Schanz JJ finds that ultra-violet light renders 

 proteins less soluble, possibly an account of its deleterious 

 action on enzymes, and in this is found a reason for the 



* Jost: "Biol. Centrlbl.," 1900, 20, 625. 



f Zaleski and Suzuki: " Ber. deut. hot. Gesells.," 1897, 15, 536; " Bot. 

 Centrlbl.," 1901, 87, 281 ; Suzuki : ' Bull. Coll. Ag. Tokyo," 1898, 2, 409 ; 3, 

 241, 



Zaleski : " Ber. deut. hot. Gesells., 1909, 27, 56. 



Loew: id., 1917, 50, 909. 



|| Montemartini : " Atti. R. Inst. Bot. Pavia," 1905, II., 10, 20. 



IT Baudisch : " Zentr. Bakt. Parasit.," 1912,32, 520. 



** Jakobi : " Biol. Centrlbl.," 1898, 18, 593. 



ttLutz : " Bull. Soc. Bot. France," 1902, 48, nS. 



t Schanz : " Ber. deut. hot. Gesells,," 1918, 3$, 619. 



SeeVolI,,p. 353, 



