132 THE ROLE OF NITKOCJEX IN PLANT-METABOLISM, iv., 



During the ripening of the seeds, the total nitrogen has 

 increased about six times. In the first stage, the seeds con- 

 tain 10 mgs. of protein-nitrogen. In the second stage, there 

 have been added, from external sources, 26 mgs. and 11 mgs., 

 respectively ; and, in the final stage of development, the 

 perfectly ripe seeds have received a further increment of 

 40 mgs. and 2 mgs. of each, respectively. 



In Table iii., are given the relative amounts of the 



protein- and nonprotein-nitrogen in per cent, of the total 



nitrogen, where it is seen that the protein-ratio increases, 



while the nonprotein simultaneously diminishes, throughout 



the same stages of development. 



Table iii. 

 Table ii. expressed in per cent, of total N : — 



Stage Protein-N. Nonprot.-N. 



1 62-5% 37-5% 



2 68 32 



3 80-0 20 



Conclusions. — From these results we may draw the con- 

 clusion that, with the entrance of nitrogenous substances into 

 the seeds, there is a simultaneous increase in the amounts of 

 both protein and nonprotein nitrogen-compovmds, the mature 

 seeds containing the largest amount of each. There is, thus, 

 no evidence that nonprotein-nitrogen has been transformed 

 into protein-nitrogen, but rather that the nonprotein-nitro- 

 gen, at least in part, is represented by a residue of unsuitable 

 material left in each case*. If the latter consisted of plastic 

 material available for the protein-synthesis, we should expect 

 it, in the perfectly ripe seed, to be almost entirely consumed. 

 On the contrary, in all ripe seeds that have hitherto been 

 examined, there still remains a considerable residue of non- 

 protein-nitrogen, and this condition remains practically un- 

 altered throughout the dormant state. 



In a previous paper (Part ii.)t a number of such deter- 

 minations are given, showing the amounts of protein- and 

 nonprotein-nitrogen in various seeds. 



• Aidm p. 129 

 + Petrie — These Proceedings, 1908, xxxiii., p.842. 



