Oct. 21, 1918 



Catalase and Oxidase Content of Seeds 



167 



The dry seeds apparently showed somewhat greater oxidase activity 

 than the imbibed seeds, either germinated or not germinated. The 

 differences, however, are probably only apparent, as the ground imbibed 

 seeds at the time of weighing contained a higher percentage of moisture 

 than the ground dry seeds. If one assumed a moisture content of 8 per 

 cent for the powder from the dry seeds and a moisture content of 26 per 

 cent for the powder from the imbibed seeds, the intensity of activity 

 would be identical when calculated to a dry-weight basis. 



The ground sprouts were considerably more active than the whole 

 seeds, but the ratio is no greater than would be expected from the com- 

 parison of embryo ends with caryopses (see Table XXVI) ; therefore no 

 increase in activity upon germination is indicated. 



OXIDASE ACTIVITY OP NONLIVING STRUCTURES 



A very interesting fact is the relatively high oxidase activity of non- 

 living structures in which catalase activity is very slight and respiration 

 presumably absent — viz, the bracts or scales which inclose the mature 

 caryopse^ of Sudan grass and Johnson grass and the dry abortive or 

 sterile florets of Johnson grass.^ Johnson grass and amaranthus seeds 

 showed greater activity than the other kinds of seeds. It was at first 

 thought that this fact might be related to the intense pigmentation of 

 the scales in one case and of the pericarps in the other. As Table XXXI 

 shows, comparative experiments with scales and caryopses proved the 

 contrary. 



Table XXXI. — Oxidase activity of nonliving structures 



' Each fertile floret in Johnson grass is accompanied by a sterile floret which never develops a caryopsis. 



