438 PHYSIOLOGY OF THE FUNGI 



2. Influence of light on spore discharge. This experiment demonstrates 

 the phototrophic response of sporangiophores and perithecial beaks and 

 the discharge of the spores toward the source of Hght. For a discussion 

 of this subject, see Buller (1934), Use species of Piloholus, Sordaria, or 

 Pleurage. 



3. Influence of aeration on sporulation. Choanephora cucurbitarum is 

 an excellent species to use in demonstrating the need for adequate aeration 

 for the production of conidia. Grow the fungus on agar in Petri dishes. 

 Some of the dishes may be sealed with Scotch tape, w^hile the lids of others 

 may be raised to permit free exchange of gases. 



4. Longevity of spores. This may be designed as a long-time experi- 

 ment to determine the longevity of spores of several fungi under different 

 conditions of storage. It may be continued from year to year, tests for 

 the ability to germinate being made every few months. 



5. Action of fungicides and fungistatic agents. These experiments 

 should be outlined to show the effectiveness of various agents in prevent- 

 ing spore germination. For references, see Chap. 11 and Horsfall (1945). 

 These agents include the action of sulfur, copper, 8-hydroxyquinoline, anti- 

 vitamins, and ultraviolet radiation. 



6. Action of antibiotics against fungi. The specificity of the action of 

 some antibiotics is easily tested against growth or spore germination of 

 some common fungi by the use of penicylinders in agar plates flooded 

 with spores. 



7. Inheritance of physiologic characters. (A) The inheritance of vita- 

 min or amino-acid deficiency may be demonstrated by crossing deficient 

 mutants of Neurospora with a self-sufficient strain (see Beadle, 1946, and 

 Chap. 18). {B) The inheritance of bioluminescence may be demon- 

 strated by crossing the North American and European strains of Panus 

 stypticus (see Macrae, 1942). 



REFERENCES 



Beadle, G. W.: Genes and the chemistry of the organism, Am. Scientist 34: 31-53, 



1946. 

 BuELL, C, and W. H. Weston: Application of the mineral oil conservation method 



to maintaining collections of fungus cultures, Am. Jour. Botany 34 : 555-561, 1947. 

 Buller, A. H. R.: Researches on Fungi, Vol. VI, Longmans, Roberts and Green, 



London, 1934. 

 Clayton, C. N.: The germination of fungous spores in relation to controlled humidity, 



Phytopathology 32: 921-943, 1942. 

 Fennell, D. I., K. B. Rapeb, and M. H. Flickinger: Further investigations on the 



preservation of mold cultures, Mycologia 42 : 135-147, 1950. 

 Georg, L. K. : a simple and rapid method for obtaining monospore cultures of fungi, 



Mycologia 39: 368-371, 1947. 

 Greene, H. C., and E. B. Fred: Maintenance of vigorous mold stock cultures, Ind. 



Eng. Chem. 26: 1297-1298, 1934. 



