58 THE SYNTHESIS OF PROTEINS 



dwarf habit of alpine plants which are subjected to a high 

 degree of insolation. Bovie * draws attention to the efficiency 

 of the extreme ultra-violet rays, the so-called Schumann rays, 

 and points out that the photolysis of protein and of protoplasm 

 increases with the diminution in the wave length of the incident 

 light; in the extreme ultra-violet region, the amount of 

 chemical change is proportional to the product of the light 

 intensity and the time of exposure. 



HYDROLYSIS OF PROTEIN ON GERMINATION. 



The protein content of a seed is a reserve food which must 

 be hydrolyzed before it can be translocated and made available 

 for the growing parts. The hydrolysis of proteins yields amino 

 acids, such as leucine, asparagine, and tyrosine, both in the 

 organism and in the test tube. From the facts of animal 

 physiology there is no doubt that amino acids, the products of 

 the hydrolysis of protein food in the alimentary tract, are recon- 

 structed to form protein in the various tissues after their passage 

 through the walls of the intestine into the blood stream. There 

 is reason to suppose that the same sequence obtains in the 

 plant. Thus Zaleski f found that during the ripening of pea 

 seeds there was an increase in the amount of the protein at the 

 expense of the amino acids and organic bases, as indicated by 

 nitrogen determinations of these compounds. 



The results were not so well marked for all seeds ; thus under 

 similar conditions but little protein synthesis took place in the 

 maize, whilst in the sunflower there was a diminution of protein. 



Of these dissociation products of proteins, asparagine is 

 amongst the more conspicuous in the plant. It occurs in the 



* Bovie : " Bot. Gaz.," 1916, 61, i. 



f Zaleski: " Ber. deut. hot. Gesells.," 1905, 23, 126; " Bern. hot. 

 Zentrbl.," 1911, 27, 63, 



