Oct. 21, I918 



Catalase and Oxidase Content of Seeds 



147 



In Sudan grass the caryopsis was divided into a distal and proximal 

 portion by cutting it crosswise just distal to the embryo. The proximal 

 embryo portion was somewhat larger than the distal endosperm portion. 

 As shown in Table IX, the embryo portion is more than twice as active 

 as the complete caryopsis and several times as active as the endosperm 

 end. Here, again, the embryo has very high catalase activity in com- 

 parison with the endosperm. 



Table IX. — Catalase activity of the distal and proximal ends of the caryopsis of Sudan 

 grass collected at Khartum, Africa {igil?). Immature and mature grains separated 

 with a vertical air-blast separator 



Table X shows the relative activity of caryopses, the bracts inclosing 

 them, and the sterile florets of Johnson grass. As one would expect, the 

 nonliving and nonfunctioning parts show low catalase activity. They 

 likely also show very low respiratory activity. The data of this section 

 show that the catalase activity of the various organs of the grains of 

 grasses parallels the physiological activity of these organs. The catalase 

 in the endosperm, caryopsis bracts, and sterile florets may be a residuum 

 of previous physiological activity. This seems to be the case, at least 

 with the last two organs mentioned, for in them catalase activity shows 

 an enormous fall with one year of dry storage. In this time it falls to 

 one-seventh, or even one-tenth, its activity in the fresh but well-ripened 

 seed. A later section shows a time fall in the catalase of the caryopsis 

 of grasses, but the rate of fall in this is much slower. 



Table yi.^Catalase activity of various organs in a samph of fohnson grass seeds 



