EFFECTS OF RADIUM RAYS ON PLANTS 1001 



kations of K in the protoplasts, thus confirming carher conclusions of 

 Nadson and 2olkevi6. 



A. Sartory, R. Sartory, and J. Meyer (70, 70a) studied the formation 

 of perithecia in Aspergillus fumigatus Fresenius under the influence of 

 radium. In their first paper they state that they made use of Aspergillus 

 fumicatus [sic] "because its characters and properties are known and 

 fixed." Four culture media were employed: glucose nondissociated ; 

 glucose dissociated by sodium chloride; saccharose nondissociated; 

 saccharose dissociated by sodium chloride. The work was divided into 

 two parts: (a) A series of exposures on all four media distributed over a 

 period of 15 days and at increasing doses of from 150 to 750 microcuries 

 and 1.2 to 2.4 millicuries (strong doses). Observations were made 12 hr. 

 after each exposure, (b) A series of exposures on all four media with 

 "strong" irradiations for 2 hr. at a dosage of 7.2 millicuries. Under the 

 various conditions the following results were recorded: (a) A stimulation 

 of the formation of the reproductive apparatus. The conidiophore 

 swelling was replaced by a tufted growth (formes peniciliennes) ; the 

 sterigmata assumed pronounced giant forms. When the dosage was 

 strong, these results were more pronounced, (b) Cultures on non- 

 dissociated media exposed discontinuously to 3 to 7.2 millicuries showed 

 a retardation of the appearance of the reproductive structures and a 

 modification in the form of the mycelial threads. The authors note that, 

 in a nondissociated medium, the radiation increases the reducing power 

 of the organism and lowers the hydrogen ion concentration of the medium. 

 On the other hand, in the dissociated medium, the irradiation diminishes 

 the power of the organism to reduce saccharose and increases the hydrogen 

 ion concentration. 



In two subsequent papers, these authors describe experiments which 

 lead them to the conclusion that the action of radium rays on Aspergillus 

 fumigatus [sic], cultivated on a medium of carrot juice gelatin (pH = 4.7), 

 dissociated by sodium chloride, and only on that medium, causes the 

 formation of fertile perithecia, with well-defined asci and ascospores. 



In 1926, Stoklasa referred in a general way to experiments he had made 

 since 1906, which have yielded cumulative evidence that radioactivity 

 affords an important means of attacking biological problems. All plants, 

 he says, are weakly radioactive. He notes that the primary step in 

 respiration is always intracellular, and it is this — a reducing process — 

 which is increased by radium rays, especially the beta rays. The rays 

 furnish an impulse to the rearrangement of the atoms in the molecule 

 of sugar, resulting first in the formation of lactic acid from which arise 

 carbon dioxide, alcohol, and finally acetaldehyde and acetic acid. It is 

 the oxidation processes, caused by oxidase and peroxidase, that are 

 stimulated by the alpha rays of radium, forming oxidation products which 

 are finally split into carbon dioxide and hydrogen. "Through our 



