Studies of Bacillus Radicicola of Canada Field Pea 41 



Results 



In both tests there was a certain amount of infection due to other 

 sources than the inoculating materials. In the first test three of the 

 thirteen plants used as controls developed nodules, while m the second 

 test thirteen of the thirty-six control plants developed nodules. It was 

 noticed, however, that, as a rule, if contamination took place subsequently 

 to the inoculation and the plants were examined within four weeks after 

 planting, the nodules due to the contamination were small and developed 

 on the lateral roots near the surface of the soil, whereas nodules resulting 

 from inoculation always appeared first on the taproot and were larger. 

 Nevertheless, the results as sho'um in the two tallies do not allow any 

 clear-cut deductions. The plants of the first test (table 5) were examined 

 three weeks after planting; the plants of the second test (table 6) were 

 kept for four weeks, which probably accounts for the larger number of 

 nodules on those plants. 



It appears certain that B. radicicola remained alive and retained its 

 infecting power in practically all the substances for forty-six days. Car- 

 borundum gave the poorest results. The plants inoculated with this 

 substance developed only small nodules, mostly on the side roots — a fact 

 pointing to subsequent infection. As regards the two series, much better 

 inoculation was obtained from series 2 in both tests. In the first test 

 99 plants were inoculated, with the cultures of series 1. These plants 

 produced 191 nodules, which is an average of 1.9 nodules per plant. The 

 88 plants inoculated with the cultures from series 2 produced 417 nodules, 

 w^hich is an average of 4' ,7 nodules per plant. From similar calculations 

 for the second test, it is found that the average number of nodules per 

 plant was 9.2 in series 1, and 12 in series 2. In both tests the plants 

 inoculated with the cultures of series 2 produced more nodules than 

 those inoculated Tv-ith the cultures of series 1. The drj-ing of the substances 

 in series 1 either reduced the mfecting power of B. radicicola, or reduced 

 the number of the organisms, or had both results. 



EXPERIMENT 11 

 INFLUENCE OF HYDROCHLORIC ACID, SODIUM HYDROXIDE, AND 

 CANE SUGAR, IN VARYING CONCENTRATIONS 



In this experiment B. radicicola of alfalfa was isolated and identified 

 according to the procedure described in Part I of this paper. The 



