HYPOBIOSIS IN FUNGI 1 1 1 



aerobic conditions, while furfural-induced activation is irre- 

 versible^^. 



Various nutrients have been recognized as indispensable 

 factors in conditioning cell activation. Resting spores of many 

 fungi are deficient in the ability to synthesize amino acids or 

 vitamins and require external supply of these materials. Ryan-o 

 showed that the amino acids leucine, lysine and proline brought 

 about spore germination in Neurospora mutants deficient in 

 these materials. 



The conidia of Glomerella cingulata have, according to Lin-^ 

 special nutritional requirements for germination. A very low 

 rate, or absence of germination was observed in distilled water 

 or glucose solution not containing inorganic material, such as 

 magnesium and phosphorus. Additional instances attesting to 

 the importance of nutrients in germination have been cited by 

 various authors^' "^' --' -^. There are indications that spore 

 germination may be facilitated in the case of vitamin-deficient 

 fungi by supplying the vitamins in question-^. The percentage 

 germination of spores of a mutant strain of Fitsariwn fructi- 

 genwn is correlated to the thiamine content of the spores--. 



Germination may be greatly accelerated by the presence 

 of actively metabolizing plant tissues. The actively metabo- 

 lizing tissue may belong to higher plants or to fungi distinctly 

 different from, or the same as the fungus forming the spores 

 under consideration. According to W. Brown--^, spores of 

 Botrytis cinerea. Monilia fnictigena and of several other fungi 

 germinate more profusely in drops of distilled water placed on 

 certain plant parts of the host and non-host, than in distilled 

 water alone. Leach-^ demonstrated a similar effect with the 

 spores of the bean anthracnose fungus Colletotrichum Jinde- 

 muthianunu and Noble-^ obtained 85 to 98% spore germination 

 of Urocystis tritici with the aid of uninjured seedlings of wheat 

 or the non-host rye. The activation required presoaking of the 

 spores for three or four days. Christensen's-'' experiments prove 

 that spores of Hehmnthosporium sativum failed to germinate 

 when kept in distilled water for more than one year, but gerrni- 



References p. 116 



