Aug.2, I930 Daily Development of Kernels of Hannchen Barley 419 



their highest capacity. In figure 1 1 are given the dry-matter contents 

 of kernels in 1916 and 1917. For the first 17 days after flowering the 

 curves of the two years practically coincide. After the seventeenth day 

 the rate of deposit decreases in 1917 but is maintained for several days 

 in 191 6. This is due, probably, to lack of sufficient water after this date 

 in 1917, the effect of which is noticeable in all the results reported. The 

 gain is surprisingly uniform for the most part. In each season, the 

 curve is essentially a straight line from the sixth until the eighteenth 



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Fig. 10. — Graph showing average wet weights of kernels from flowering to maturity in plot i in 1917. 

 Numerals at ends of lines indicate days from flowering. 



day. This is interesting in its relation to the general laws of plant growth. 

 In a developing plant, where the new tissue added becomes immediately 

 productive of nutrient material for growth, the increase is accelerated in 

 geometrical ratio. The curve of growth, in this case, can be reduced to 

 a straight line in plotting by the use of logarithmic paper. In the case 

 of kernel growth, by the fourth or fifth day after flowering, the maximum 

 leaf and sheath surface is exposed. The plant food metabolized is 

 diverted to the storage tissues of the kernel, and, since the productive 

 tissues remain constant in amount, the curve of kernel growth is a 

 straight line. 



