EFFECT OF CERTAIN COMPOUNDS OF BARIUM AND 

 STRONTIUM ON THE GROWTH OF PLANTS 



By J. S. McHargue 

 Chemist, Kentucky Agricultural Experiment Station 



INTRODUCTION 



Although it has been known for more than a century that plants 

 are able to extract appreciable amounts of the relatively insoluble 

 compounds of barium contained in soils, very little scientific investiga- 

 tion has been made to determine whether or not the compounds of this 

 element have any specific function in the vegetable economy. Because 

 compounds of barium are poisonous when taken into the animal body, 

 there appears to be a general impression that these compounds would 

 exert a similar influence upon plants. 



In a former investigation ^ the writer has shown that small amounts 

 of barium can be readily detected and determined quantitatively in the 

 ash of tobacco, com, potatoes, and a number of other plants grown under 

 normal conditions in the field. Since soils contain only very small 

 amounts of barium, necessarily in the form of relatively insoluble com- 

 pounds, it is a question of considerable scientific interest how and why 

 it is that notable amounts of this element are absorbed and apparently 

 assimilated by plants, under normal conditions of growth. The object 

 of the present investigation was to determine the effect of some of the 

 well-known compounds of barium and of the closely related metal, 

 strontium, upon the growth of plants. 



EXPERIMENTAL WORK 



Preliminary experiments consisted in growing plants in nutrient solu- 

 tions to which were added certain compounds of barium, soluble as well 

 as insoluble. It soon developed that plants could be grown in a nutrient 

 solution containing moderate amounts of barium nitrate or carbonate, 

 whereas an equal amount of the chlorid or sulphate produced a decided 

 toxic effect. After having determined that the plants selected for the 

 water-culture experiments were tolerant of barium carbonate and nitrate, 

 it was decided that a method more nearly approximating the normal 

 conditions under which plants are grown would be a better procedure. 

 Accordingly the plan was adopted of growing the plants in barium-free 

 sand contained in earthenware pots to which the necessary basal plant- 

 food ration could be added, together with the desired compounds of 

 barium. 



1 McHargue, J. S. Thb occurrence op barium in tobacco and other plants. In Jour. Amer. 

 Chem. Soc, v, 35, no. 6, p. 826-834- 1913- 



Journal of Agricultural Research. Vol. XVI, No. 7 



Washington, D. C. Feb. 17, 1919 



rh K;ey No. Ky.-? 



(183) 



98355°— 19 2 



