214 The Development of the Grain of Wheat 



Fig. 20, showing the percentage of nitrogen and phosphoric acid in 

 the straw, has been drawn in order to demonstrate how the feeding value 

 of the straw declines as the grain forms. 





6 9 12 15 18 21 24 27 30 33 36 days 



Fig. 19. P0O5 in whole plant and in grain, 1908. 



8 



6 _ _:^^- 



2 



1 







N 



3 6 9 12 15 18 21 24 27 30 33 36 days 



Fio. 20. % nitrogen and P0O5 in dry matter of straw, 1908. 



It should of course be remembered that in these results no account 

 is taken of the root of the plant, which cannot be removed from the soil 

 without both loss of the fine roots and the introduction of foreign 

 matter ; migration will no doubt take place from the root to the seed, 

 but the weight of root bears too small a proportion to that of the 



