Studies of Bacillus Radicicola of Canada Field Pea 



53 



As far as could be ascertained by these results, there was no reduction 

 in the infecting power of the organisms when they were propagated and 

 kept on the above media for three weeks. When these results are com- 

 pared with the data in tables 9 and 10, it is seen that those cultures in 

 which no visible growth took place produced either no inoculation or very 

 poor inoculation, and that the cultures in which the organisms multiplied 

 produced good inoculation. 



Second test of infecting power (table 12) 



In this test the cultures were ten weeks old. The exact number of 

 nodules on each plant was counted, and from these figures calculations 

 were made of (1) the total number of nodules in each flowerpot, (2) the 

 average number of nodules per plant in each flowerpot, and (3) the average 

 number of nodules per plant of all the plants inoculated with the same 

 culture. It was hoped that the averages would give a more nearly ac- 

 curate measure of the infecting power of the different cultures. The data 

 are given in table 12. Fifteen plants were inoculated with each culture, 

 five plants being grown in each flowerpot. 



TABLE 12. Infecting Power of Cultures Ten Weeks Old 



a 



-§T3 



S 



3 



a 



m 

 o g^ 



Number of 

 nodules on 

 each plant 



CO 



XI 







«« ft 



II 



« 03 



Average number of nod- 

 ules per plant in each 

 flowerpot 



aumber of nod- 

 er plant pro- 

 3y the culture 





03 



53 



CO 

 § 





CI 

 03 



Average 

 ules p 

 duced 



1 



Medium 334 + 2 per cent 

 cane sugar 



1 



2 

 3 



14 



22 



4 

 10 



1 



2 





 9 



12 

 12 



31 

 55 



6.2 

 11.0 



8.6 





















2 



Medium 334 + 2 per cent 

 cane sugar 



4 

 5 

 6 



6 

 12 

 14 







4 



7 



3 



15 

 6 



10 



12 



2 



4 

 10 



7 



23 

 53 

 36 



4,6 

 10.6 



7.2 



7.5 



4 



Medium 334 + 10 per cent 

 cane sugar 



7 

 8 

 9 



5 

 10 

 10 



7 



8 



15 



14 



14 

 18 



12 

 8 

 5 



12 

 "5 



50 

 40 

 53 



10.0 

 10.0 

 10.6 



10.2 



