Aug. a, 1920 Daily Development of Kernels of Hannchen Barley 423 



way with those of Schjerning, but inasmuch as his samples were less 

 frequently taken, close comparison is not readily made. 



CHANGES IN WATER CONTENT 



The percentage of water in the kernel is highest at flowering time, 

 when over 80 per cent of the caryopsis is water. From flowering until 

 maturity the percentage of water constantly decreases. At maturity 

 the water content has fallen to about 40 per cent. The decrease in per- 

 centage is very uniform, as may be seen in figure 2. The curves of 1916 



s>o 

 e& 



a-^ 

 A? 

 80 



70 

 %7^ 



%70 



o 



— — ■)?* nj — " — 



IZZZZZZZZZZSifZZZZZZZZZZI 



_^ o 



^^ 



Sg 



A." 

 ^_ — 



JL_» 



^ ^ ^ ■^ ^ o^ 7 ^ s> /'o // /^ /^s A* /s /G' ^^/ff ys) ^i?^y ^^^^^■^^.s^^^^l"^ 



Fig. 14. — Graph showing percentage of moisture in morning and evening samples of Hannchen barley 

 in 1917. The average for the day is indicated by the line. The average morning determinations are 

 indicated by circles, and evening determinations by crosses. 



and 1 91 7 are essentially identical. As previously remarked, the coinci- 

 dence of these curves is evidence of the exceptional opportunity 

 afforded at Aberdeen for comparative studies in development. 



The loss of water in percentage is much more rapid than in the results 

 obtained by Brenchley. At Aberdeen the rate is almost 2 per cent a day. 

 At Rothamsted the rate during infiltration was in the neighborhood of i 

 per cent a day, although the rate was higher than this at times. 



The effect of evaporation during the day was noticeable. The morning 

 sample usually showed a gain in percentage of moisture over that of the 

 night before. The loss of water during the day was rapid, evidently 

 exceeding the normal loss, due to the incident of growth. This extra- 

 normal loss and its recovery are shown in figure 14. 



