392 



GROWTH OF PLANTS 



Table 42. De-sugaring: Effect upon Cane Sugar by Transference of Tubers 

 from Storage at 5° C (41° F) to Storage at 27° C (81° F). Storage Started 



Oct. 25, 1940 



Cane sugar. Table 42 shows the effect of high-temperature storage fol- 

 lowing low temperature on the cane sugar content of potato tubers. As is 

 the case with reducing sugars, varieties differ considerably in the amount of 

 cane sugar they accumulate during cold storage; varieties Irish Cobbler, 

 Green Mountain, and Delaware accumulate considerable and Russet 

 Rural, Carman No. 3, Sir Walter Raleigh, Early Ohio, and Heavyweight 

 much less. In all varieties high-temperature following low-temperature 

 storage does not cause marked de-sugaring so far as cane sugar is con- 

 cerned. 



Effect of the Period of Storage at Room Temperature on Later Sugaring 

 at Low Temperature 



Holding tubers at room temperatures for considerable periods after 

 harvest and before storage at low temperatures decreases the rate of 

 sugaring at the low temperature. Fig. 154 shows the relation for re- 

 ducmg sugar accumulation for the 1941 crop. The curves are composite 

 curves for five different varieties (Irish Cobbler, Carman No. 3, Green 

 Mountam, Bliss Triumph, and Katahdin) put into cold storage after four 

 different periods of room temperature storage. The most rapid accumula- 

 tion of reducing sugar occurred when the tubers were held at room tempera- 

 ture only 10 to 12 days before they were put at 5° C (41° F), and slowest 

 accumulation occurred in those held at room temperature 71 to 74 days. 

 Those held at room temperature for 108 to 111 days were second from 

 lowest, and those held at this temperature for 131 to 134 days were next to 



