ON THE FORMATION OF ARGININ IN CONIFEROUS PLANTS. 29 



a) 



b) 



c) 

 140.0 

 59.6 



Total nitrogen. 



100.0 



120.0 



Albuminoid nitrogen. 

 Asparagine nitrogen. 

 Nitrogen in phospho- 



20.0 



5S-3 



2 r. 1 



tungstic precipitate. 

 Other nitrogen. 



20.7 



25.9 



6.6 



38.1 



27.3 



41.4 



We can now safely conclude that the greater part of the 

 nitrogen absorbed as ammonium salts, is accumulated as organic 

 bases in the shoots, and as we found no noticeable increase of 

 asparagine even when treated with ammonium chloride solution, 

 it is highly probable that in coniferous plants, organic bases 

 (arginin !) are synthetically formed, instead of asparagine. 



Plate I. shows the increase of organic bases (N. in phos. 

 tungstic ppt.), especially arginin, in the shoots of Pinus Thun- 

 bergii by the addition of ammonium salts. The black lines 

 refer to shoots treated with half saturated gypsum solution in 

 the full day-light. The red lines refer to shoots treated with 

 0.5% ammonium chloride solution, half saturated with gypsum 

 in the full day-light. 



Note: — The total nitrogen was determined l>y Kjeldahl's method, and albuminoid 

 nitrogen by that of Stutzer's. The filtrate of copper hydrate precipitate was acidified 

 with sulphuric acid and some excess of phospho-tungstic acid solution was added, when a 

 strong white precipitate was formed. The precipitate was collected on a filter, washed 

 with 5% sulphuric acid, dried and subjected to Kjeldahl's method for nitrogen determina- 

 tion. The nitrogen in phospho-tungstic precipitate chiefly consists of that of organic 

 bases. 



The filtrate of phospho-tungstic precipitate served for the determination of asparagine 

 nitrogen. For this purpose caustic baryta was added to the filtrate until the solution 

 became alkaline and caused the phospho-tungstic acid in solution to precipitate. The 

 solution was then filtered, and the filtrate was acidified with sulphuric acid to precipitate 

 the excess of baryta as barium sulphate. To the filtrate from barium sulphate, was 

 added some pure concentrated hydrochloric acid (10 c.c. cone, hydrochloric acid to each 

 100 c.c. of the solution), and the mixture boiled in a reflux cooler for 2 hours and distilled 

 in the usual way, care being taken to neutralize the solution with caustic soda until it 

 became faintly acid and then to make it slightly alkaline by the addition of a little 

 magnesia. 



It is also quite important to prove the absence of ammonia in the shoots, either 

 mechanically adhering to them or preserved unchanged in the plant cells, because 

 phospho-tungstic acid precipitates it together with the organic bases, and thus becomes 

 a source of error. For the detection of ammonia, the powdered sample was extracted 

 with cold water, and to the extract, a few drops of Nessler's reagent was added. But the 



