IQ2IJ 



PACK—JUNIPERUS 



51 



the seedlings gradually attained the ratio 1:1. This rise in the 

 respiratory quotient was probably due to the oxidation of carbo- 

 hydrates and the more intense respiration of the seedlings. 



Table XVIII gives the results of intramolecular respiration. 

 The method used was that of Nicolas (26). The point to be 

 noted here is the low i/N ratio (the intramolecular or anaerobic 

 respiration divided by the normal respiration) for the seedlings. 



Peroxidase was more generally present than oxidase. Quanti- 

 tative oxidase activity determinations were made with the Bunzel 

 apparatus. These results showed that there was no appreciable 

 increase of oxidase activity until after germination. 



TABLE XVIII 



Intramolecular respiration of juniper seeds, no. 10, at 25° C. (7 cc. volume 



The results of catalase determinations are given in table IX, 

 which gives the average of a great number of experiments. It was 

 found that (1) when seeds were placed under ordinary germination 

 conditions at 5 C. the increase of catalase activity gave a measure 

 of the after-ripening; (2) the gain in catalase activity above that 

 of air-dry seeds was greatest at 5 C. in a germinator; (3) the gain 

 at the other temperatures was slow at best; and (4) seeds soon 

 lose their catalase activity when in a germinator at temperatures 

 above 25 C. The precautions used in the catalase determinations 

 have been stated. 



Crocker (6) speaks of the rise in vigor of seeds, as shown by 

 their resistance to fungal attack, during after-ripening. The 

 juniper seed is protected against fungi before germination by the 

 heavy lignin coat. It was found that juniper seeds which had not 

 been after-ripened soon succumbed to fungal growths with the 

 removal of the coats. After-ripened juniper seeds, however, 

 when freed from the coats, withstood dense fungal growths. 



