135 



THE HOLE OF NTTllOGEN IN PLANT-METABOLlSlVl. 



Part V. — The Occurrence of Potassium Nitrate in 



Plants. 



By J. M. Petrie, D.Sc, F.I.C, Linnean Macleay Fellow 

 OF the Society in Biochemistry. 



(From the Physiological Laboratorij of thf UnivP-vsitij nj 



Sydney.) 



Potassium nitrate is one of the principal forms in which 

 plants receive their nitrogen from the soil. Although this 

 salt has been detected in small quantities in very many 

 plants, it accumulates and is stored, as a reserve, in only a 

 few. It is, therefore, of interest to record the occurrence of 

 a comparatively large amount of this salt in the evergreen 

 shrub, Solandra ymndifloni, N.O. Solanacese. 



This plant was collected at Grafton, N.S.W., by Dr. H. 

 G. Chapman, in May of 1909, when the autumn leaves were 

 beginning to fall; and for. the special purpose of investigat- 

 ing the alkaloid contained in it. 



E ape rime n fed. — Leaves weighing 20 kilogms., were air- 

 dried, disintegrated, and extracted with hot water acidvilated 

 with tartaric acid. This water-extract was evaporated to a 

 thin syrup, treated with alcohol, and filtered. From the 

 clear solution, the spirit was removed by distillation under 

 diminished pressure ; the residue left in the still was dissolved 

 in water, filtered clear, and the solution concentrated on the 

 water-bath. There now separated, on cooling the solution, 



