Oct. 21, 1918 



Catalase and Oxidase Content of Seeds 



151 



Table XVII shows the relation of catalase activity to age and vitality 

 in the seeds of Johnson grass, Sudan grass, and Amaranthus retroflexus. 



Table XVII. — Relation of catalase activity and age in dry-stored seeds 

 [Only mature seeds used. Catalase determinations made between Sept. 26 and Oct. 5, 1917I 



Kind and source of seeds. 



Date 

 of col- 

 lec- 

 tion. 



Oxygen liberated after — 



3 

 tain. 



S 

 min. 



Ger 



mina- 

 tion 

 tem- 

 pera- 

 ture. 



Percentage of germina- 

 tion in — 



3 da. 



5 da. 



7 da. 15 da 



Johnson grass: 



Arlington Farm, Va 



Do 



Fort Worth, Tex 



Sao Paulo, Brazil 



Bushnell Co., St. Louis, Mo. . . 

 Soudan grass- 

 Sherman, Tex 



Khartum, Africa 



Khartum, original importation 

 Amaranthus retroflexus: 



Pullman, Wash 



Arlington Farm, Va 



Chicago, 111 



Do 



Do 



Allenton, Mo 



Fort Collins, Colo 



East Lansing, Mich 



Amaranthus graecizans: 



Pullman, Wash 



Amaranthus blitoides: 



PuUman, Wash 



1917 

 19 16 

 1911 



1908 

 1905 



1916 

 1911 

 1908 



1917 

 1917 

 1917 

 1915 

 1914 

 1894 

 1894 

 1894 



1917 



1917 



Cc. 



6-3 

 4-3 

 3-2 

 1.6 

 1-7 



4.2 

 3-8 

 2.0 



8.3 

 8.4 

 7-9 

 8.S 

 6.3 

 8.7 



4.4 

 3-S 



Cc. 



13-7 

 8.6 

 6-5 

 3-1 

 3-3 



9.1 

 7-5 

 4.2 



18. 1 

 13- 9 



16.8 

 16. 5 

 IS- 7 

 13-8 

 12-5 



8.S 

 7-3 



Cc. 



19.0 

 II. 4 

 8-5 

 4.2 

 4.4 



12.4 

 10. I 

 S-8 



22.7 

 16. 7 

 20. 7 

 20.9 

 19. 2 

 15- S 

 15.2 

 22.7 



10. s 

 9.1 



Cc. 



27.4 

 16.0 

 II. 6 

 6.0 

 6.3 



17-3 

 14. 2 



26.8 

 19.8 

 24.9 

 24.8 

 22.3 

 18.5 

 17. o 

 26.8 



13.0 



II. o 



"C. 



25-40 

 25-40 

 25-40 

 25-40 

 25-40 



2S 

 25 

 25 



40 

 40 

 40 

 40 

 40 

 40 



99 

 30 

 37 

 94 

 100 



99 



88 

 98 



100 

 91 

 100 

 100 

 100 



100 

 100 

 100 

 100 

 100 



100 



S8 



In Johnson grass the fall evidently begins with harvest and continues 

 for an indefinite time. The degeneration of catalase seems most rapid 

 during the first year and slows down considerably during later. periods. 

 The same thing apparently happens in Sudan grass, but data are lacking 

 for the 1 91 7 crop. In both a very considerable fall in catalase activity 

 occurs, with little or no fall in vitality. There is also considerable 

 catalase activity when seeds fail to germinate at all. In the 9-year-old 

 Sudan grass the percentage of germination is still very high (98 per cent), 

 although the catalase activity has fallen to less than one-half that of the 

 I -year-old, and probably to less than one-third that of the freshly har- 

 vested. In the 9-year-old seeds there is somewhat lower vigor, as shown 

 by the rate of growth of the seedling and the predisposition of the seed 

 to fungus attack. In Sudan grass the catalase activity seems to be an 

 excellent indicator of age. It is apparently a better indicator of age than 

 it is of vitality. The same relation holds for Johnson grass, in which the 

 catalase activity falls continuously with age except for the poor crop of 

 1908, which shows a slightly lower activity than the 1905 crop. 



