«9°9l 



SCHREINER &• REED— OXIDIZING POWER OF ROOTS 



38i 



for the higher plants and pointed out its bearing upon the composition 



of nutrient solutions. 



made up from 



absorbed by growing plants, e. g., calcium nitrate and potassium 



sulfate. Where calcium 



more rapidly than Ca, with the result that the solution becomes 

 increasingly alkaline. In the case of potassium sulfate, the plants 

 take up K more rapidly than S0 4 , with the result that the solution 

 becomes acid. In the experiments which were made upon this prob- 



made 



the solutions when the experiment was terminated. A measured 

 quantity of solution was boiled in a platinum vessel to drive off C0 2 , 

 and then titrated. The results of these determinations are shown 

 with the other results in Table X. 



TABLE X 



Oxidation and growth of wheat plants in solutions which became acid or alkaline 

 ^ the result of plant growth. Relative growth measured by tran^aUon. 



Xo. 



Solution 



I 



2 



3- 



4.. 



5- 

 6.. 



7 



30 p.p.m. 

 30 p.p.m. 

 30 p.p.m. 

 66 p.p.m. 

 66 p.p.m. 



Acidity at 

 termination 



of the 

 experiment 





Alkalinity at 



termination 



of the 

 experi ment 



Relative 

 oxidation 



10. 



Control in distilled water 



Ca as Ca (N0 3 ) 2 

 Ca as CaCl 2 

 Ca as CaC0 3 

 S0 4 as (NH 4 ) 2 S0 4 

 S0 4 as K 2 S0 4 

 N0 3 as NaN0 3 

 Kas 

 N0 3 

 63 p.p.m. K as 



no 3 



K 



K as K 2 HP0 4 



'■ 100 p.p.m. 



35 P-P-m- 



9- 



$ 100 p.p.m. 



100 p.p.m. 

 63 p.p.m. 

 63 p.p.m. 



KCl 



as NaN0 3 



KCl 



I as KNO 



123 

 46 

 78 



20I 

 02 



283 



w/75°° 

 nj 1 0000 



Neutral 



tf/5000 



tt/7500 

 w/7500 



n/ 2 0000 



w/5000 



Neutral 



n/ 1 0000 



100 

 401 



107 



175 

 102 



100 



401 



97 

 638 



These results show that six of the nine solutions b*«ne d£j»e. 



<*» became acid, and one remained neutral. Grow* ^<T££ 

 *«e less in the acid solutions than in those wh.ch becam alkalme 

 «ough in the case of calcium chlorid the result was q u » 

 *« ease of potassium sulfate and potassium chlond , t pa i& Jp 

 s »n may be due to the effect of the potassium, which usua y 

 «» increase oxidation materially, but such is not the case » ith ammo 





