RADIANT ENERGY 83 



hydrate be at hand. Zaleski and Suzuki * 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 assimilation 

 is not a photochemical process, and that light is only of indirect 

 importance in providing one of the means for the formation 

 of carbohydrates. f This opinion also is held by Loew.J 

 Using Chlorella as a subject for investigation, Muenscher § 

 found that it can synthesize protein in total darkness when 

 inorganic salts of nitrogen are supplied and provided that 

 carbohydrate in adequate amount is available. There is thus 

 no doubt that light is inessential for the formation of pro- 

 teins but Baudisch || thinks that their formation in darkness 

 is abnormal and provides no proof that the process is not 

 a photochemical one under normal conditions ; he considers 

 that the synthesis in darkness is 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 quan- 

 tities of carbohydrate are available, the synthesis of proteins, 

 in darkness, may stop at the formation of amides,^ which 

 some plants, e.g. Algs such as Pleurococcus and Raphidium, 

 and the Fungi Eurotium and Penicillium, can directly assimi- 

 late.** 



There is available but little exact knowledge regarding 

 the specific action of invisible wave-lengths of radiant energy 

 which may be concerned in the different phases of protein 

 metabolism. Schanz ff finds that ultra-violet light renders 

 proteins less soluble, possibly on account of its deleterious 

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

 habit of alpine plants which are subjected to a high degree of 



♦Zaleski and Suzuki: " Ber. deut. bot. Ges.," 1897, 15, 536; " Bot. 

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

 3. 241. 



f Zaleski : " Ber. deut. bot. Ges.," 1909. 27, 5 6 - 



% Loew : id., 191 7, 50, 909. 



§ Muenscher : " Bot. Gaz.," 1923, 75» 249. 



|| Baudisch : " Zentr. Bakt. Parasit.," 1912, 32» 520. 



If Jakobi ; " Biol. Centrlbl.," 1898, 18, 593- 



** Lutz : " Bull. Soc. Bot. France," 1902, 48, 118. 



tt Schanz : " Ber. deut. bot. Ges.," 1918, 3<S 619. 



XX See Vol. I. 



6* 



