Journal of Applied Microscopy 



and 



Laboratory Methods 



Volume VI. JANUARY, 1903. Number 1. 



Culture Methods with Uredineae. 



The cultivation of rust fungi is a process so simple and the results so 

 interesting that it seems strange that it is not more generally practiced. 

 Problems of the greatest importance are capable of solution by this means, 

 and at the same time nothing can be more attractive in class demonstration. 

 In this article some suggestions will be given concerning methods of culture 

 with these fungi. 



At the outset it is important to note that these fungi differ from many 

 others of the lower forms of life, particularly the bacteria, in that no particular 

 advantage is gained so far as we yet know in the use of artificial culture 

 media. Many different kinds of culture media have been used with very 

 little effect beyond the results that can be obtained in ordinary water cultures. 

 There is occasionally this difference, that some of the spore forms will produce 

 germ tubes of a little greater length, and growth will proceed a little more 

 rapidly than when simple water cultures are used, but this is about the only 

 difference that has been noticed. All growth stops uniformly at a certain 

 period even in the most carefully sterilized cultures. The writer spent 

 considerable time in an effort to devise a successful artificial medium which 

 would simulate as nearly as possible the conditions obtained in the ordinary 

 wheat leaf. In the case of the common wheat rust, the actual juices of the 

 wheat leaf were used, permeating a solid medium as nearly similar in 

 structure to the leaf as could be made. This, however, failed of its purpose 

 like all other media. 



Methods of Germination. In ordinary spore germination, the best apparatus 

 for general purposes, that the writer has found, is the ordinary Van Tieghem 

 cell, consisting, as is well known, of a slide with a glass ring affixed to the 

 center within which several drops of water are placed, the material being put 

 in a drop of water in the center of a covered glass which is inverted over 

 this cell. All the different spore forms germinate readily in water, but, as 

 already hinted, in some cases a more rapid germination can be obtained by 

 the use of certain other media — such as solutions of nitrates, beef broth and 

 sugar solutions. Germination goes on best at about the ordinary temperature 



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