618 



A. W. Gahton and D. C. McCune 



Table 6. The effect of GA application on the growth and peroxidase acti\-ities of 

 dwarf and tall peas and corn. Peroxidase substrate was pyrogallol; data obtained on 

 Klett-Summerson photoelectric colorimeter with a blue filter. 



* Standard error. 



t Difference significant at the 1 per cent level by analysis of variance. 



the conclusion that GA induces some alteration of the peroxidase 

 complex of enzymes in the plant such that the relative activities to- 

 ward different substrates are altered. This is not altogether surprising, 

 since it is well known that the peroxidases of plants such as horse- 

 radish and sweet potato are resolvable by electrophoresis into about 

 five components (11, 13). We therefore decided to subject the peroxi- 

 dases of the dwarf and normal corn to electrophoretic separation, in 

 an attempt to delineate further the nature of the changes in peroxi- 

 dase activity produced by GA. 



The procedure was as follows: 75 g. dry potato starch was washed 

 repeatedly with distilled water, then dried by filtration on a Biichner 

 funnel. To the dried starch were added 33 ml. of buffer 0.02 M, pH 

 6.1, KHoP04-NaoHP04. The resulting slurry was poured into a trough 

 40 X 2.5 X 10 cm. and ca. 9 ml. of exuded solution removed by fdter 

 paper blotters. A segment 1 cm. long was then removed from the 

 middle of the block, and replaced by a slurry of 1.2 ml. of centrifuged 

 plant homogenate (see paragraph below) in 1.8 g. dry washed starch. 

 The block was then placed in an E-C Co. electrophoresis apparatus 

 and exposed to 400 V (ca. 2.8 mA) for 12 hrs. in a cold room main- 

 tained at 2° C. After 12 hrs., the block was cut into 1 cm. segments, 

 each of which was placed in a centrifuge tube containing buffer. The 



