46 



BULLETIN 1406, U. S. DEPARTMENT OF AGRICULTURE 



three. From 20 to 25 apples, weighing from 2,500 to 3,000 grams, 

 were used in each experiment, At 60° and 85° duplicate lots of each 

 variety were run and two or three determinations made on each lot. 

 The data, as recorded in Table 5, are calculated in milligrams and 

 cubic centimeters of carbon dioxide evolved per kilogram of fruit 

 per hour and cubic centimeters of oxygen consumed per kilogram 

 of fruit per hour. 



From the data on the weights of carbon dioxide evolved, it is at 

 once apparent that there is a rather close relationship between the 

 respiration rate and the rate of softening of the different varieties. 

 Grimes Golden, for example, evolved carbon dioxide at a rate be- 

 tween 4 and 5 milligrams per kilogram of fruit per hour at 32° F. ; 

 between 8 and 9 milligrams at 40° ; between 29 and 30 milligrams 

 at 60° ; and from 60 to 70 milligrams at 85°. Thus at 40° the rate 

 was slightly less than double that at 32°, and that at 60° was about 

 six times that at 32° and more than three times that at 40°. At 85° 

 the respiration was more than double the rate at 60°. Kef erring to 

 the data for the Arlington Experiment Farm Grimes Golden in 

 1923-24 in Table 4, it is apparent that 6 days were required for full 

 ripening at 85°, 13 days at 60°, 33 days at 40°, and 81 days at 

 32°. Thus at 60° the softening was six times as fast as at 32°, and 

 the respiration rate was about six times the rate at 32°. At 85° 

 both the softening and respiration rates were slightly more than 

 double the rates at 60°. The ripening rate at 60° was two and one- 

 half times the rate at 40°, while there is an even greater difference 

 in respiration rate. In general, however, there is a very close agree- 

 ment between the rates of respiration and softening for Grimes 

 Golden. 



Table 5. — Respiration of apples in relation to temperature 



Variety, station, and temperature 



Run No. 



Length 

 of run 

 (hours) 



Per kilogram of fruit per hour 



C0 2 



evolved 

 (mgr.) 



CO2 



evolved 



(c. c.) 



Oj 



consumed 

 (c. c.) 



tion ratio 

 CO2-O1 



Grimes Golden, Rossi yn, Va. 

 32° F. (0° C.) 



40° F. (4.5° C.).. 



60° F. (15.5° C). 



85° F. (29.5° C). 



Jonathan, Yakima, Wash. 

 32° F. (0° C.) 



40° F. (4.5° C). 



60° F. (15.5° C). 



1 



2 



3 



1 



2 



3 



1A 



2 A 



IB 



2B 



1A 



2 A 



3 A 

 IB 

 2B 

 3B 



1 

 2 

 3 



1 

 2 

 3 



1A 

 2 A 

 3A 

 IB 

 2B 

 3B 



288 



310>2 



143 H 



187 



190M 

 47^ 

 43^ 

 47J/ 2 

 43M 

 23^ 2 

 22M 



23>| j 

 22M 

 23?i I 



432^ ! 

 405 



331 I 

 235 j 



191M I 



237 

 46M I 

 68^ , 

 47H I 

 46^ 



m% 

 471^ I 



4.84 

 4.73 

 4.71 

 8.55 

 8.32 

 8.16 

 29.2 

 29.2 

 29.6 

 29.0 

 70.4 

 68.3 

 62.2 

 73.3 

 69.2 

 63.5 



3.25 



3.50 



3.61 



6.79 



7.35 



7.45 



29.1 



24.7 



23.3 



30.9 



25.9 



25.0 



2.46 

 2.41 

 2.40 

 4.35 

 4.23 

 4.15 

 14.85 

 14.85 

 15.06 

 14.75 

 35.82 

 34.75 

 31.66 

 37.30 

 35.21 

 32.31 



1.66 

 1.78 

 1.84 

 3.46 

 3.75 

 3.80 

 14.84 

 12.60 

 11.88 

 15.76 

 13.21 

 12.75 



2.03 



2.16 



2.02 



4.06 



3.89 



3.85 



14.16 



14.50 



14.17 



14.34 



32.96 



33.34 



27.69 



33.69 



33.73 



28.05 



1.50 

 1.70 



3.22 

 3.19 

 3.41 

 12.48 

 11.99 

 11.41 

 13.24 

 11.41 

 11.94 



1.21 

 1.11 

 1.19 

 1.07 

 1.09 

 1.08 

 1.05 

 1.02 

 1.06 

 1.03 

 1.09 

 1.04 

 1.19 

 1.11 

 1.04 

 1.15 



1.11 

 1.05 



1.07 

 1.17 

 1.11 

 1.19 

 1.05 

 1.04 

 1.19 

 1.16 

 1.07 



