INFLUENCE OF FOOD AND ENVIRONMENT 129 



Alcohol in certain proportions appears to enhance 

 vegetative growth and retard fruiting. This was very 



marked in Aspergillus and Sterigmatocystis in concentra- 



4 

 tion. Botrytis produced greatest abundance of mycelium 



in and . Clark considers that this may be due to 

 16 32 



alcohol acting as a stimulant rather than as food. 



Ono has also shown that very dilute solutions of many 

 mineral salts accelerate vegetative growth, while at the 

 same time retarding or checking the formation of repro- 

 ductive organs, in Aspergillus m'ger, and Penidllium 

 glaucum, also in certain of the lower algae. Under these 

 conditions the energy normally used up in spore-formation 

 is diverted towards the formation of an excess of vegetative 

 hyphae. 



Clark, Bot. Gaz., 28, p. 289 and 378 (1899). 

 Ono, Journ. Coll. Sri. Imp. Univ. Tokyo, 13, p. 141 

 (1900). 



INFLUENCE OF FOOD AND ENVIRONMENT ON 



THE FORMATION OF REPRODUCTIVE 



ORGANS IN FUNGI 



Klebs has investigated the effect of chemical and physical 

 factors on the formation of reproductive organs. In ex- 

 perimenting with Saprolegnia mixta, it was found that a 

 total suppression of both sexual and asexual organs occurred 

 when the fungus was supplied with an abundance of nourish- 

 ment. An abundant formation of zoospores can be secured 

 by starving the fungus, as by growing it in water. On the 



l 



