ioo RESPIRATION 



halepensis, catalase activity runs parallel to respiration, a corre- 

 lation which does not obtain in the seeds of Amaranthus* In 

 Acer saccharinum, Jones f found that the intensity of respiration 

 of seeds during the process of desiccation at 25 C. at first de- 

 creases, then rises to a maximum and finally a gradual decline 

 to zero : with regard to the catalase activity, there is a slight 

 initial increase, then a decrease as desiccation proceeds, during 

 which process there is also a gradual decrease in peroxidase 

 activity. In the early stages of germination, when respiration 

 is high, there is a large increase in catalase activity. From 

 these results it would appear that catalase and respiration are 

 more closely correlated than are oxidase and respiration. It 

 is to be remembered, however, that catalase and oxidase are 

 closely related enzymes and that agreement has not been 

 reached regarding the interrelation of these enzymes in the 

 oxidizing complex, an aspect of the subject which has before 

 been considered.^ 



There appears to be no general concurrence of opinion re- 

 garding the precise mode of action of these respiratory 

 enzymes. Palladin is one of the few who have formulated a 

 more or less complete scheme of the mechanism, but before 

 considering his thesis, it is desirable briefly to draw attention 

 to the salient phenomena presented in the anaerobic respira- 

 tion of higher plants. It has been mentioned that the higher 

 plants, although normally aerobic, may be facultatively anaerobic : 

 the anaerobic respiration of germinating pea seeds, for example, 

 is a commonplace of the laboratory. In such instances the car- 

 bon dioxide evolved certainly has no relation to initial gaseous 

 oxygen ; it represents a dissociation product of the substances 

 physiologically consumed. Comparison with the alcoholic fer- 

 mentation of sugar is an obvious pursuit and the two phe- 

 nomena show remarkable resemblances. Anaerobic respiration 

 is an extravagant method of obtaining energy and gives rise to 

 carbon dioxide and ethyl alcohol which in a sense is wasted un- 

 less further oxidized. The amount of alcohol and carbon 

 dioxide produced is a variable quantity depending on the 



* Crocker and Harrison : " Journ. Agric. Res.," 1918, 15, 137. 



t Jones: " Bot. Gaz.," 1919, 69, 127. 



JVol.iL, p. 396. 



See Kostytschev: "Journ. Russ. Bot. Soc.," 1916, I, 182. 



