ON THE RESERVE PROTEIN IN PLANTS. 



8l 



By exposure to boiling 5% NaCl solution the proteosomes 

 were coagulated. This was observed with the petals of Punka 

 and of Astilbe and the root of Thesium. 



Millon's and biuret reactions are best made on objects free 

 from tannin, as for instance, the root of Thesium. Both reac- 

 tions were obtained after fixation of the proteosomes by dilute 

 ammonia after the modification, described by Locw and Bokorny 

 (Bot. C. 1889) ; biuret reaction was also obtained by boiling 

 with a concentrated solution of copper sulphate solution, washing 

 and moistening with concentrated solution of caustic potash. 



A small branch of Quercus dentata, showing in the young 

 leaves as well as in the bark, during development in the spring, 

 a large quantity of active albumen, was left for twelve days with 

 the stem immersed in water. At the same time two of the 

 leaves were placed in a small vessel with water. In the latter 

 case, the respiration was of course restricted to a certain extent 

 for obvious reasons. Both objects were placed in a corner of a 

 room with only a moderate amount of light x) for twelve days, 

 and then for two days in the dark. Now the leaves on the 

 branch commenced to show brown spots, whereupon a micros- 

 copical examination was made and it was found that there was 

 no longer any starch in either case, but while the leaves on 

 the branch no longer showed the reaction of active albumen, 

 those kept in water still gave a moderate reaction. It might be 

 objected here that there was just as much albumen still present 

 in the former leaves, but it was only changed to passive albumen. 

 But it has been shown by E. Schulze that protein compounds 

 are transformed in plants kept in darkness into amido-acids, and 

 that finally asparagin remains as a chief product. 



The gradual disappearance of the active albumen from the 

 leaves stands in close relation to the formation of asparagin ; 

 I found that while the fresh leaves of Quercus glandulijera con- 

 tained 0.218% of nitrogen in the form of asparagin (determined 

 after Sachse-Kormann) , those kept for seven days in darkness 

 contained 0.606%; therefore the asparagin was increased near- 

 ly three times the original amount. 



A similar experiment was made with the leaves of Pczonia 



1) At the lower end of the branch a fresh surface was cut repeatedly in order to 

 secure the sufficient ascent of water. 



