790 Journal of Agricultural Research vol. xx.No. io 



DISCUSSION OF RESULTS 



In studying the tables it should be borne in mind that the figures rep- 

 resent percentages based on the plants themselves and have no bearing 

 on the yield of the various constituents per unit of area. For example, 

 the proteids decline in percentage as the plant grows. This does not 

 mean, of course, that the amount of the proteids per given area decreases, 

 but rather that as the plant grows and increases in weight the proteids 

 do not increase in the same ratio. 



Too much importance must not be placed on slight differences in com- 

 position from stage to stage of growth. Because of the difficulties in 

 sampling whole plants, small differences due to unavoidable errors are to 

 be expected, and conclusions are safest when drawn from the general 

 trend of the results rather than from particular figures. 



Considering the sunflower plant first, it will be noted that the dry 

 matter steadily increases as the plant grows older. This, of course, is 

 what would be expected, but the fact is rather surprising that, even after 

 the rays had all fallen and the seeds had become dry and mature, the 

 plant still contained more moisture than the corn contained at the time 

 it was ready for the silo. 



The proteids, both total and albuminoid, show a tendency to decline 

 as growth proceeds. This is somewhat contrary to what might be ex- 

 pected from the highly nitrogenous character of the seed. 



The reducing sugars rise and then gradually decline. The nonreducing 

 sugars steadily and rapidly decline throughout the whole period of growth. 

 In the first stage there is one and one-half times as great a quantity of 

 nonreducing sugars present as reducing sugars. This relation, however, 

 is quickly changed, and in the last stage there is nearly three times as 

 much of reducing sugars present as nonreducing. The percentage of 

 starch is small, rising and falling with no apparent relation to the change 

 in percentage of the sugars. 



Turning now to the corn plant, it will be noted, as would be expected, 

 that the dry matter steadily increases as the plant grows older. The 

 proteids, both total and albuminoid, decline slowly but quite regularly. 

 The sugars, both reducing and nonreducing, rise and fall but have an 

 upward trend until the kernels begin to mature, when there is a sharp 

 drop, accompanied by a sudden increase in the starch. This is at the 

 stage when the plant is storing starch in the kernels and is the stage usu- 

 ally selected for ensiling. The ratio of reducing and nonreducing sugars 

 changes, but within a somewhat narrow range. The reducing sugars 

 always greatly exceed the nonreducing. The starch rises and falls up to 

 the stage when the kernels begin to mature. Between the milk stage 

 and what may be called the silage stage the starch increased from 2.87 

 per cent to 24 per cent. 



Comparing the sunflower and the corn plants, it will be noted that the 

 chief difference in the constituents studied lies in the amount and char- 



