62 PLANT RESPIRATION 



Plant Material CO2: C2H6OH 



Roots of Daucus Caroia 100: 72 



Green grapes 100: 86 



Green grapes 100 : 74 



Blue grapes 100:95 



Blue grapes. 100: 88 



Blue grapes 100: 81 



Blue grapes 100: 74 



Potato tubers 100: 7 



Potato tubers 100: 2 



Potato tubers 100. o 



Potato tubers 1 00 : o 



Leaves of Tropaeolum majus 100: 45 



Leaves of Tropaeolum majus 100: 24 



Leaves of Tropaeolum majus 100: 17 



Seedlings of Sinapis sp 100: 50 



Seedlings of Sinapis sp 100: 32 



The noteworthy behavior of potatoes also appears in these 

 experiments. It is very likely that in the case of dormant 

 potatoes there is a deficiency of the enzymes of fermentation. 

 Kostychev^ succeeded by wound stimulation in increasing the 

 ratio COoiCoHoOH in potatoes to 100:35 or 100:28, thus 

 inducing a noticeable production of alcohol. Still a very con- 

 siderable excess of CO2 is formed even after wound stimulation. 

 Hence the anaerobic respiration of potato tubers is not wholly 

 identical with the typical alcoholic fermentation. Whether 

 other products than alcohol and CO2 appear in anaerobic 

 respiration remains undecided. In all cases in which a con- 

 siderable excess of CO2 appears with the formation of alcohol, 

 a formation of other substances is certainly very likely," for it 

 would be scarcely conceivable that organic substances from 

 which the excess of COo is hberated should, in the absence of 

 oxygen, entirely decompose into COo and II2O without forming 

 other products. Older investigators reported that molecular 



1 Kostytschew, S. Bcr. d. bot. Ges. 31: 125. I9i3- [Stoklasa (Ibid. Vol. 44, p. 250. 

 1926) reports that such low proportions of alcohol were never found in his experiments with 

 potatoes.) 



" Under anaerobic conditions, the ground tissues of germinating peas and 

 beans were found by Neuberg und Gottschalk (Biochem. Z. 160: 256. 1925) to 

 produce traces of acetaldehyde. Kostychev himself notes later that this sub- 

 stance may be formed in quantities sufficient to interfere with the determination 

 of alcohol. — Ed. 



