NITROGEN ATOMS IN THE SUNFLOWER 



907 



T.\BLE 1 



Leaves 



Nitrofjen content 

 in in{,'m 



Young 



Intermediary 



Old 



17.6 



74.6 



653.3 



15.6 



80.2 

 150.9 



15.2 

 38.0 

 30.3 



trichloroacetic acid was added, the solution obtained containing 5 per cent of 

 this substance. By this process, the proteins were precipitated. They were filtered 

 off and washed with 5 per cent trichloroacetic acid. We will denote this precipitate 

 as fraction I. The trichloroacetic filtrate was evaporated, supplying fraction II. 

 The residue of the extracted leaves is denoted as fraction III. All three fractions 

 were kjeldahlized, supplying three ammonia fractions which were neutralized 

 with hydrochloric acid. 



The total nitrogen content of these samples was determined as ammonium 

 by titration. To obtain the ^^N content of the samples from the ammonia distillates 

 obtained, nitrogen was prepared by the method described by Rittenberg, 

 Keston, Rosebuhy and Schoenheimer. The ^'N content of these samples was 

 determined with the mass-spectrograph. 



' Containing presumably also nitrogen split off from proteins during drying of tlie leaves. 



