242 SCIENCE REMAKING THE WORLD 



storage conditions. The market demands a firm potato 

 as it has better cooking qualities. The sprouting period 

 is characterized by high destructive metabolism, result- 

 ing in loss from the tubers of starch and other solids. 

 Loss of water through the sprouts may also be high. 

 The final result of these processes is the extreme wilting 

 of the tubers. 



External conditions have a profound influence on the 

 physiology of potatoes in storage. Undesirable changes 

 in the tubers may be controlled or checked and their 

 storage life prolonged by a proper combination of stor- 

 age temperature, humidity, and ventilation. The most 

 favourable combinations of these factors for the differ- 

 ent periods in the storage life of the potato can be de- 

 termined only when we possess accurate and controlled 

 data on the individual effects of these storage factors. 



When human beings are well the temperature of their 

 bodies is practically constant regardless of the external 

 temperature. Plants are not so fortunate, as the tem- 

 perature in their tissues changes with that around them. 

 This explains why temperature is so important in shap- 

 ing the life activities of plants and in controlling their 

 destiny. 



The researches of Muller-Thurgau clearly demon- 

 strated the relationship between storage temperature 

 and the accumulation of sugar in the tubers. Po- 

 tatoes attain their maximum sweetness after a few 

 weeks' storage at a temperature of 32 F. and not as a 

 result of freezing, which does not occur until the tem 

 perature falls to 28 or 26 F. Potatoes will accumulate 

 a small amount of sugar at 42 F. but practically none 



