798 



Journal of Agricultural Research 



Vol. XX, No. ii 



of movement of soluble carbohydrates from the stems and cob to the 

 kernels and the rate of hydrolysis of cane sugar in the kernels are both 

 controlled by the rate of starch formation. Most of the starch that is 

 stored in the kernels during ripening is formed from carbohydrates 

 already stored in the stem and cob when kernel formation begins. The 

 intensity of respiration does not change the ratios of the different car- 

 bohydrate constituents in the ripe corn. The carbohydrate transforma- 

 tions being reversible, their final equilibrium positions are maintained. 



S /O 

 OJYS 



Fig. i. — Comparison of early and late crops of sweetcorn in respect to changes in percentage composition 

 in equal lengths of time. Early crop (Aug. 3 to 18) indicated by solid lines. Late crop (Sept. 20 to Oct. 

 5) indicated by broken lines. 



EFFECT OF SEASON ON THE RATE OF RIPENING 



Two crops of corn from the same source of seed were planted so that 

 the first crop would ripen in August and the second in the cool autumn. 

 In order to compare the ripening rates of the early and late crops, it was 

 necessary to find a measure of the rate of ripening. The decrease in the 



