212 The Development of the Grain of Wheat 



in the grain sets in. It is evident that assimilation does not cease until 

 migration is nearly complete. Respiration continues later still, because 

 the weight of the whole plant falls in the last week. 



Fig. 17 shows the nitrogen in the whole plant and in the grain ; here 

 again, though the curve is not very smooth, there is no evidence of any 

 cessation in the intake of nitrogen until within a few days of the date 

 of cutting. 



36 days 



Fig. 16. Dry weights of whole plant and grain, 1908 (whole plant = weight of 

 1000 grains + weight of straw calculated as equivalent to 1000 grains). 



Fig. 18 shows the ash in the whole plant and in the grain ; similarly 

 it is seen that the intake of ash by the plant, though not so pronounced 

 during the period under review, continues to within a week of cutting. 

 The amount of ash then becomes stationary, the slight fall indicated in 

 the last week being within the limits of experimental error. Exactly 

 similar conclusions are to be drawn from the phosphoric acid curves set 

 out in Fisf. 19. 



