1920] 



JONES— MA PLE SEEDS 



M5 



Catalase activity increases slightly during the first few days of 

 desiccation, but decreases gradually thereafter. This activity 

 seems to align itself in a general way with respiratory activity, 

 which remained high for a considerable time. With germination 

 the catalase activity increases enormously, appearing to be closely 

 correlated with metabolic activity. There is not a sudden drop in 

 the catalase activity at the time of loss of viability, as one might 



TABLE II 



Catalase activity accompanying desiccation and first stages 



of germination 



Condition of seeds of seedlings 



No. of cc. of Oa given off by 1 gm. of 

 dry weight in 



5 minutes 



Fresh seeds collected May 25 (191 8) 

 Desiccated at 25 C. for 3 days 





3 

 10 



14 

 18 

 22 

 26 



34 



42 



Desiccated in laboratory for 8 months . 

 Seedlings with radicle 1 cm. long . . . . 



3 

 4 



5 



952 



i°35 

 ito6 



977 



1075 

 1022 



868 



73i 

 688 

 461 

 380 



1245 

 1717 

 2106 

 2438 

 3216 



10 minutes 



1248 

 1373 

 1447 

 1341 

 1359 

 1259 

 1098 



979 

 909 



593 

 500 



iS65 

 2055 

 2566 

 3060 

 4472 



expect, but a gradual decrease correlated with respiratory activity 

 and water loss. After a storage for 8 months under laboratory 

 conditions the catalase activity was reduced more than one-half 

 below that of the fresh seed. 



Oxidase and peroxidase 



Peroxidase activity is very intense in the fresh seeds. A dark 

 blue color is obtained immediately upon addition of alcoholic 

 solution of benzidine and a drop of dioxygen. As desiccation 

 progresses there is a gradual decrease in peroxidase activity. In 

 one-year-old dead seeds there is only a very pale blue color evident 



