Aug. 3, 1920 Development of Barley Kernels in Clipped Spikes 453 



Table III. — Average percentage and weight per kernel of dry tnatter, water, nitrogen, 

 and ash in kernels from normal and clipped spikes of Manchuria barley at St. Paul, 

 Minn., in igi^ — Continued 



CLIPPED SPIKES 



The deposition of ash, on the other hand, is maintained in the kernels 

 of dipped spikes for a much longer period. It is only in the final days of 

 maturation that the total ash per kernel of the normal spikes exceeds 

 that of the kernels of the cHpped spikes. In Table III it will be seen 

 that in percentage of ash the case is reversed. The kernels of the clipped 

 spike have an appreciably higher percentage of ash. That the total is 

 higher in the kernels of normal spikes is due to the greater weight of those 

 kernels. In the experiment with Hannchen barley at Aberdeen several 

 other determinations of ash were made, and a discussion of the significance 

 of the ash content is better made after the results from that variety have 

 been presented. 



The nitrogen content per kernel is shown graphically in figure 5. 

 During more than half the period of growth there is little difference in 

 the rate of the deposit of nitrogenous materials in the spikes. From 

 July 23 to July 29 there is apparently a more active deposit in the normal 

 spikes. The graphs become confused as the kernels ripen. As a whole, 

 there is not much difference between the two. As there is a definite 

 difference in the dry weight, the deposit of carbohydrates must be 

 decidedly greater in the normal spikes during the last half of the growing 

 period. 



The water per kernel is a good index of development. In normal 

 development the water rapidly increases after fertilization and quickly 

 attains its maximum. It then remains stabilized, or nearly so, as long 

 as growth is efficiently maintained. When growth is checked or matura- 

 tion begins, the water content drops slowly until complete ripeness occurs. 

 After complete ripeness it drops still more rapidly for two or three days. 

 It will be seen in figure 6 that the water content of the kernels from 

 clipped spikes is about equal to that of the kernels from normal spikes 



