i6o 



Journal of Agricultural Research 



Vol. XV, No. 3 



lot the seeds were grown at 20° C. until the coleoptiles were 4 to 6 cm. 

 long. The germinated seeds were then allowed to dry for seven days in 

 laboratory air before they were ground. As is seen from Table XXIV, 

 the catalase activity is about doubled by germination to the stage 

 reported above. Germinated Johnson grass seeds showed similar 

 behavior. The reported activity for germinated seeds may be low, 

 for, as has been shown, drying commonly decreases catalase activity in 

 seeds. There seems no doubt that this rise in catalase activity is accom- 

 panied by a rise in respiratory intensity, for Rischawi (33, p. 253), has 

 shown that when wheat grains germinate and grow in darkness at 21° C. 

 the respiratory intensity rises from a value of about 14 the first day to 

 50 on the tenth day, where it is maintained until the sixteenth day. It 

 gradually falls from there on, owing to the exhaustion of stored foods, 

 until it attains a value of 15 on the twenty-sixth day. 



Table XXIV. — Catalase activity of germinated and ungerminated Sudan grass seeds 



SOLUBILITY OP THE CATALASE OP SEED 



Loew (30) found that the catalase of various plants consisted of two 

 sorts: insoluble, or a-catalase, and soluble, or jS-catalase. The relative 

 proportion of these two constituents varied greatly in different plants 

 as well as in different organs of the same plant. It was thought well to 

 see whether there is any correlation between the relative time and heat 

 stabilities of the catalases of amaranthus and Johnson grass seeds and 

 the proportions of insoluble and soluble catalases in them. The data 

 on this point are reported in Table XXV. In these experiments either 

 0.2 gm. of seed powder suspended in 10 cc. of water or the filtered 

 extract of 0.2 gm. of seed powder in 10 cc. of water was used for each 

 determination. Ten cc. of dioxogen were added to this, and the volume 

 of oxygen liberated was measured. An excess of calcium carbonate 

 (CaCOa) was kept in contact with the materials at all stages of the 

 process to protect against injury by acids. 



Four different treatments were used for the materials of each sort of 

 seeds: (i) Powder added to the water just before the determination 

 and the whole suspension used in the determination; (2) powder sus- 

 pended in the water and shaken for one hour at 25° C. and the whole 

 suspension used in the run; (3) powder treated as the last but only the 

 filtrate passing through a C. S. & S. 595 filter paper used in the deter- 



