CATALASE 151 



than the endosperm, and this also holds for the intensity 

 of respiration. In air-dry fruits of Andropogon halepensis, 

 catalase activity runs parallel to respiration, a correlation 

 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 

 decreases, then rises to a maximum and finally gradually 

 declines 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 perox- 

 idase activity. Nemec and Duchon % state that the catalase 

 activity of seeds is closely correlated with their vitality as 

 measured by the percentage of germinations, Gracanin,§ on 

 the other hand, finds that this activity is not a good index 

 of vitality since dead seeds may possess active catalase. 

 Shull and Davis || find that the upper seeds of Xanthium, 

 which have a delayed germination, exhibit a lower catalase 

 activity than the lower seeds, which on germination show 

 an increased catalase activity. Rhine ^f observed a decrease 

 in catalase during the early stages of germination, followed by 

 an increase in the later stages ; there is thus a wide divergence 

 in the respiration and the catalase curves. Lautz ** also draws 

 attention to this initial decrease, followed by an increase, in 

 the catalase activity of germinating seeds ; he also observed 

 that the rapid increase in respiration following a rise in tem- 

 perature is not accompanied by a corresponding increase in 

 catalase activity. This is contrary to the observations of 

 Burge and Burge ff who found that the catalase of Spirogyra 

 varies directly with temperature and illumination, temperature 

 having the greater effect. They conclude that whatever affects 

 respiratory metabolism, similarly affects catalase activity, 

 and suggest that catalase is of prime importance in respiration. 



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



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



I Nemec and Duchon : " Compt. rend.," 1922, 174, 632. 



§ Gracanin : " Biochera. Zeit.,'' 1927, 180, 205. 



|| Shull and Davis : " Bot. Gaz.," 1923, 75, 268. 



If Rhine : id., 1924, 78, 46. 



** Lautz : " Amer. Journ. Bot.," 1927, 14, 85. 



ft Burge and Burge : " Bot. Gaz.," 1924, 77, 220. 



