46 Transactions Tennessee Academy of Science. 



Some Effects of Parasitic Fungi on Leaf 



Tissue 



By E. S. Reynolds, University of Tennessee. 

 (Abstract.) 



A considerable amonnt of information has been gathered in the 

 past upon the general effects of parasitic fungous invasion upon 

 the cell contents of leaf cells. It was found by numerous micro- 

 tome sections that the cells are affected in quite diverse ways, de- 

 pending upon the particular disease and the particular host 

 studied. In some cases the cell organs are killed, evidently by a 

 very strong poison, while in others the organs are stimulated into 

 excessive growth, resulting in enlarged nuclei or an increase in 

 their number. In still other cases the nuclei are greatly changed 

 in form, from crescentic to obovoid or irregularly dumb-bell 

 shaped. Some of these latter forms seem to precede or to be the 

 result of direct division of the nucleus. The chloroplasts most 

 often are reduced in size or are missing entirely. The general 

 cytoplasm seems often to be changed into, or replaced by, oil drops, 

 or at times a granular deposit, the composition of which was not 

 determinerl. These changes are equivalent to those which have 

 been previfuisl)- rei)orted by others as occurring in other kinds of 

 ])arasitic tissue. 



