Studies of Bacillus Radicicola of Canada Field Pea 



29 





TABLE 3 (concluded) 





Substance used 



j Quantity 



added to 



300 grams 



of soil 



(grams) 



Condition of plants 



Nodule development 



f 25 



Fair g'"owth 



Few nodules 



XT"^^ > 4. 0.50 



v\ itte s peptone < ^ Of] 



2^00 



Poor growth 



Poor growth 



Poor growth 



No nodules 

 No nodules 

 No nodules 



Cane sugar ■ 



0.25 

 0.50 

 1.00 

 2.00 

 4.00 

 ! 8.00 

 16.00 



Good growi;h 



Good growth 



Good growth 



Good growth 



Poor growth 



Poor growth 



Very poor growth. . . . 



Nodules present 

 Nodules present 

 Nodules present 

 Nodules present 

 Nodules present 

 No nodules 

 No nodules 



Coutrols Nothing 



added 



Good growth 



Nodules present 



Results 

 The addition of MgS04, KH2PO4, and CaCOs in the concentrations 

 used in the experiment had a beneficial effect on the development of nod- 

 ules. Cane sugar at low concentrations had apparently no effect. At 

 the concentrations of 4, 8, and 16 grams of sugar in 300 grams of soil, 

 cane sugar was injurious, probably due to fermentation products and to 

 stimulation of the development of microorganisms injurious to the plants 

 and also to the development of nodules. The addition of KH4CI and 

 FeCla completely inhibited the growth of the plants. In the case of 

 KNO3 and Ca(N03)2 the concentration of I gram in 300 grams of soil had 

 a beneficial effect on the growth of the plant, but an injurious effect on 

 the development of nodules. A few nodules developed in the presence of 

 Ca(N03)2, but none in the presence of KNO3. The higher concentrations 

 of Ca(N03)2 and KNO3 inhibited nodule development and also caused 

 injury to the plants. 



EXPERIMENT 9 

 INFLUENCE OF CERTAIN ADDITIONAL SUBSTANCES 



The method used in this experiment was the same as in experiment 8. 

 Several additional chemicals were tested. In examining the plants, the 



