RESPIRATION IN PLANTS 
231 
agree with the Bunzel method in indicating the relative oxidase activity 
in the two ends of McCormick tubers. The colorimetric method con- 
sistently showed a greater oxidase activity in the stem half of the 
tuber, although this half always exhibited a lower rate of respiration. 
Therefore, neither method disclosed any relation between oxidase 
activity and the intensity of respiration. 
Table VIII 
Catalase and Oxidase Activity in Seed and Stem Ends, McCormick Tubers Sprouting 
Only From Seed Ends 
Date of Measure- 
ment 
Average 
Length of 
Sprouts 
Manometer Readings Expressed in Centimeters of Mercury 
Seed Ends 
Stem Ends 
Catalase 
Oxidase 
Catalase 
Oxidase 
March 20 
March 22 ..... . 
March 25 
April 6 
0 
0 
8 mm. 
12 mm. 
+ 2.4 
+ 3-1 
+ 4-0 
+ 3-6 
- 
— 2.1 
— 2.2 
— 2.25 
+ 2.1 
+ 2.7 
+ 3.1 
+ 3-0 
— 1-9 
— 2.2 
— 2.2 
— 2.1 
Average 
1 +3-36 
— 2.06 
+ 2.72 
— 2.12 
Comparison of Different Varieties: Tubers from different varieties, 
but under identical storage and sprouting conditions, were found 
Table IX 
Respiration of Tubers from Two Different Varieties. All Conditions of Experiment - 
Identical in Both Cases 
Milligrams of CO2 per Kilo per Hour 
Date of Measurement McCormick Carman No. i 
April 21 12.83 17-36 
Table X 
Catalase and Oxidase Activity in Juice from Tubers of Two Different Varieties 
Date of 
Measurement 
Manometer Readings Expressed in Centimeters of INIercury 
Catalase 
Oxidase 
McCormirk 
Carman No. i 
McCormick 
Carman No. i 
April 14 
April 23 
2-3 
2.85 
3-8 
3-15 
2.2 
2.6 
.60 
.64 
to possess different rates of respiration. This fact being established, 
experiments were next planned to determine if there is a corresponding 
