7o6 



Journal of Agricultural Research 



Vol. XII, No. II 



The proportional change in respiration for each lo-degree rise in tem- 

 perature is shown in Table XVI. The data in this table were obtained 



by employing the conventional formula -^ in which Vt represents the 



rate of respiration at the specified temperature, and F^+^o represents 

 the rate at a temperature lo degrees higher. The values at 5° and 

 15° were computed by integrating the actual data obtained at 4° to 

 25° and 35° C. 



Table XVI. — Acceleration of respiration for each lo-degree increase in temperature 



INFLUENCE OF ACCUMULATED CARBON DIOXID UPON RESPIRATION 



Muntz {1881) observed that ten times as much carbon dioxid was 

 respired when grain had access to free air as when sealed air-tight and 

 that the yield of carbon dioxid was much greater after the moisture 

 exceeded 13 to 14 per cent. 



Mangin (i8g6) found the evolution of carbon dioxid and absorption 



of O2 to be reduced when germinating seeds were put in air containing 



CO 

 up to 5 per cent of carbon dioxid. The -^r ratio was increased, indi- 



eating that absorption of oxygen was diminished more than the evolu- 

 tion of carbon dioxid. 



Duvel {1904), Babcock (191 2), Barnes and Grove (19 16), and others 

 have called attention to the reduced vitality and germination of seeds 

 stored in carbon dioxid, or in tight containers in which the respired car- 

 bon dioxid accumulated. 



In the case of grain stored under ordinary commercial conditions it 

 follows that the oxygen in the space surrounding the kernels must be 

 replaced with respired carbon dioxid. The rate of such replacement 

 will, of course, hinge upon the factors influencing the rate of respira- 

 tion. To determine the relative change in the respiration of grain stored 

 in a tight container in which the respired carbon dioxid must accumu- 

 late, the following experiment was conducted: A sample of wheat 

 containing 15.05 per cent of moisture was divided into four portions, 

 which were incubated in the usual manner at 37.8° C. At the end of i, 

 4, 8, and 12 days a cylinder was removed and the respired carbon dioxid 

 determined. The rate of respiration for the first day and the average 

 rate for each of the 4-day periods are shown in Table XVII and graph- 



