TILLETIA TRITICI 271 



The results of the two series of experiments are embodied in the 

 Table on p. 270, from which it will be seen that out of a total 

 of 28 inoculated plants 9 became diseased while 18 remained healthy 

 and one died. The percentage of infection was therefore 32-14. 

 Of the 17 control plants all remained healthy. 



In a third and earlier series of experiments which was started on 

 May 20, 1927, there were no control plants, but every grain was 

 surface -sterilised in the manner already described. The plants 

 were subjected to room temperature (about 20° C). At this 

 relatively high temperature the seedlings grew much faster than in 

 the two series of experiments already recorded, and inoculation 

 with falling basidiospores was stopped as soon as the coleophylla 

 had attained a length of about two inches. During the inoculation 

 period, the seedlings were exposed to diffused daylight. As before, 

 some of the seedlings were inoculated with Tilletia tritici, and others 

 with T. laevis. 



Of a total of 38 plants inoculated in the third series of experiments 

 10 became diseased while the other 28 remained healthy. The 

 percentage of infection was therefore 26-31. The plants inoculated 

 with T. tritici basidiospores produced only T. tritici chlamydospores, 

 while those inoculated with T. laevis basidiospores produced only 

 T. laevis chlamydospores. 



Sartoris, 1 under the experimental conditions used by him, failed 

 to obtain infection of wheat plants either from the mycelium or 

 from the basidiospores of Tilletia tritici. In the three series of 

 experiments described above, we employed exclusively secondary 

 basidiospores as a source of inoculum and we obtained results which 

 clearly prove that the secondary basidiospores of T. tritici and T. 

 laevis can and actually do cause the infection of healthy wheat seedlings. 

 Thus the view held by the older workers on Bunt, namely, that 

 the secondary basidiospores (their secondary conidia) are effective 

 inocula for the Stinking Smut disease of Wheat has been confirmed 

 by results obtained by a new and precise method. 



When secondary basidiospores have fallen on to the moist 

 surface of the coleophyllum, etc., of a wheat seedling, they ger- 

 minate at once and send out long germ -tubes which creep over the 



1 G. B. Sartoris, " Studies in the Life History and Physiology of Certain Smuts," 

 American Journal of Botany, Vol. XI, 1924, pp. 617-647. 



