Oct. 21, 1918 



Catalase and Oxidase Content of Seeds 



143 



Table III shows the effect of the reaction of the dioxogen upon the 

 catalase activity of a number of seeds. An examination of the table will 

 show that unneutralized dioxogen inhibits in all and that the magnitude 

 of the inhibition falls as the amount of powder increases. The plant 

 material apparently acts as a buffer. In the after-ripened peach seed 

 when 0.2 gm. of the seeds is used there is practically no inhibiting, while 

 it is very marked with 



0.05 gm. These relations 

 for the peach are well 

 shown by the curves in Rj 

 figure I. ^ 



-^O 



From these results it 



K3S 



is evident that one must l^j 

 look after the reaction -^ ^^ 



N 



of the hydrogen peroxid 

 in measuring the cata- 

 lase of seeds. In his 5^ ^^ 

 work with the potato ^ 

 tuber Ap pieman (/) U 

 maintained a neutral ^ ^^ 

 reaction by addingan ex- ^ 

 cess of calcium carbon- kj ^ ^ 

 ate. He showed that l^^ 

 the emulsion of ground ^ 

 tuber either contained N 



or developed sufficient kj 

 acid to injure greatly ^ 

 the catalase after stand- ^ 

 ing for a number of days >^ 

 and that this injury could 

 be avoided by grinding 

 the tuber with an excess 

 of calcium carbonate . 1 1 



^ /O 



S 



IS 



that 



/ ^ 3 ^ s 



/:>(//?/} r/o/v o/^ r//£/^cr/ou/A/A7/A/(/r£s 



- , Fig. I. — Graphs showing the effect of the acidity of dioxogen upon 



prODaOie, nowever, the catalase activity of after-ripened peach seeds; also the buffer 

 effect of the seed material; i, 0.2 gm. of seed material, dioxogen 

 ... - neutralized; 2, 0.2 gm. of seed material, dioxogen not neutralized; 3, 



activity 01 newly-ground o.os gm. of seed material, dioxogen neutraUzed; 4, 0.05 gm. of seed 

 tubers not treated with material, dioxogen not neutralized. 



calcium carbonate was partly, if not mainly, due to the acidity of the 

 hydrogen peroxid used. 



DEGREE OP PULVERIZATION 



The degree of pulverization has considerable effect upon the activity 

 of catalase. As Table IV shows, Johnson grass gives maximum activity 

 with medium fineness of the powder (70-80-mesh sieve) and very much 

 less activity with fine grinding (200-mesh sieve), as well as with much 

 coarser meal (40-mesh sieve). Crimson clover gives maximum acti\'ity 



