ON THE FORMATION OF ARGININ IN CONIFEROUS PLANTS. 45 



was not so remarkable as in the 2 former experiments. This 

 may be explained by considering that the shoots, having at first 

 been kept in the dark, lost the greater part of carbohydrates by 

 respiration and also that the chlorophyll bodies being decom- 

 posed by keeping in the dark, the assimilation of the carbonic 

 acid gas did not proceed so energetically as to prepare enough 

 carbohydrates necessary for the regeneration of arginin into 

 proteids. Also the energy of living protoplasm might have 

 been greatly diminished by keeping it in the dark. Therefore if I 

 had kept them still longer then, the shoots would have recover- 

 ed from the abnormal condition and much decrease of the bases 

 would have been observed ! We found also that the shoots 

 treated with mineral nutriments transformed much organic bases 

 into proteids. 



Plate V. shows the influence of light upon the change 

 of nitrogenous compounds in the shoots of Pinus Thunbergii. 

 The shoots were kept for 14 days in perfect darkness and 

 a portion was afterwards, exposed to the day-light for 14 days, 

 while the other portion was still kept in the dark. The black 

 lines refer to shoots kept in the dark until the end of the 

 experiment. The red lines refer to shoots, previously kept in 

 the dark, was exposed to the full day-light for 14 days. 



4. The shoots which was first exposed to full day-ligJit, 

 were afterwards kept in the dark, and the change in nitrogen 

 compounds observed : — 



a) The shoots kept in full day-light until 15th March (18 

 days after germination). 



b) The shoots were afterwards kept in the dark, from 15th 

 to 27th, with a half saturated gypsum solution. 



Number of shoots. 

 Length. 



Total dry weight. 



Dry weight of 100 shoots 



a) 

 710 



8-10 cm. 



4.750 



0.669 



b) 

 560 



10-12 



3.819 

 0.681 



In 100 parts of dry matter! 



Total nitrogen. 



a) 



3-73 



b) 



9.16 



