THE CHEMICAL PROCESSES IN PLANT RESPIRATION 1 25 



showed that ethyl alcohol can be oxidised by various seed- 

 plants either not at all or only incompletely, and in any case is 

 not to be regarded as an intermediate product of oxygen respira- 

 tion. The same result was indicated by the older work of Maze 

 and Perrier/ who undertook to test the assimilation of ethyl 

 alcohol by seed-plants. It appeared that ethyl alcohol is 

 partly esterified by leafy twigs, partly thrown off by transpira- 

 tion, but is neither oxidised nor assimilated. 



Further studies by Kostychev and his coworkers^ showed 

 that fermented sugar solutions induce an enormous increase in the 

 rate of respiration of different seed-plants, but particularly 

 that of wheat seedlings. This indicates that there are easily 

 oxidised intermediates of alcohoHc fermentation in fermented 

 sugar solutions. Hexose phosphate cannot be an intermediate 

 of oxygen respiration, for pure preparations of this substance 

 effect no increase in such respiration, according to Kostychev. 



Of course the results just described could also be interpreted 

 in another way as they were by Meyerhof,^ among others, who 

 has observed an increase in the respiration of animal tissues 

 through the influence of products of fermentation and that of 

 yeast extracts. The stimulative effect of fermented solutions 

 could be attributed to a content of coenzyme or vitamine which 

 exerts an effect on the enzymes of the seed-plants. Kostychev,^ 

 however, demonstrated a modification of the action of peroxi- 

 dase by means of fermented sugar solutions. It has long been 

 known that peroxidase preparations from various seed-plants 

 exhibit a w^eakened, specific oxidising effect. They are only 

 able to oxidise phenol groups. For example, hydroquinone is 

 oxidised to quinone by H0O2 and peroxidase, with the formation 

 of water but not of CO2. The possibility of oxidising 



1 Maze, P. et Perner. Ann. de I'inst. Pasteur i8: 740. 1904- 



2 Kostytschew, S. Biochem. Z. 15: 164. i9o8; 23: i37. 1909; Ber. d. bot. Ges. 31: 

 422,432. 1913; Kostytschew, S. und A. Scheloumow. Jahrb. f. wiss. Bot. 50: IS7. i9ii. 

 [The interpretation of these experimental results is questioned by L. Iwanow (Ber. d. bot. 

 Ges. 32: 191-196. 1914) who considers that components of the fermented sugar solutions 

 other than intermediates of alcoholic fermentation might have induced the increased pro- 

 duction of CO2 by the plants to which they were appHed. The experiments play such an 

 important part in Kostytschew's argument that they are well worth repeating for confirma- 

 tion and further analysis of the components of such solutions.] 



3Meyerhof, O. Z. f. physiol. Chem. loi : 165. 1918; 102: i. 1918. [Xaturwissen- 



schaften 7: 253-^59- 1919.] 



'Kostytschew, S. Z. f. physiol. Chem. 67: 116. 1910. 



