Dec. 13. 191S Translocation of Constituents of Seeds and Tubers 455 



EXPERIMENTS WITH CORN 



Similar experiments have been tried with com, except that the seed- 

 lings were grown in aluminum cups instead of in paraffined tubes. One 

 thousand grains of com were germinated, transferred to aluminum cups, 

 and allowed to grow for 23 days, when they began to etiolate. During 

 this time these seedlings attained a height of 9 inches. At this point 

 they were removed from the cups and dissected as follows: Leaves (2), 

 exhausted cotyledons (3), stems (4), and roots (5). (See Table III.) 

 These were controlled by the same number of whole corn grains (i) as 

 given also in Table III. These several lots of material were analyzed in 

 the same manner as the bean seedlings. In this experiment we have 

 also followed the translocation of iron and aluminum. Unfortunately, 

 the results obtained with these two last-named elements show contamina- 

 tion from the aluminum cups used in the experiment. The results of the 

 analyses of the ash of com grain and of the several parts of the seedlings 

 thereof are given in Table III. 



It will be seen from the results of these analyses that the sum of the 

 total ash of the several parts of the corn seedling exceeds the total ash 

 of the com grain by 0.9487 gm. This is doubtless to be explained by 

 the fact that iron and aluminum were taken up in considerable amounts 

 from the cups and also by contamination with small amounts of dust 

 from the outside air. It will be seen that the sum of the amounts of 

 phosphoric acid, potash, and magnesia in the several parts of the corn 

 seedling agrees with that of the corresponding amounts of these sub- 

 stances found in the corn grain, within the limits of experimental error. 

 A point of interest in this connection is that magnesia is greatly in 

 excess of lime in the grain of corn and in the several parts of the seedling 

 obtained therefrom. The amounts of lime, silicon, iron, or aluminum 

 found in the several parts of the seedling are in excess of the amounts of 

 these substances found in the grain. As already pointed out, this dis- 

 crepancy is doubtless due to outside contamination. Under the condi- 

 tions prevailing in this experiment approximately two-thirds of the total 

 mineral matter of the corn grain has been translocated to the stems, 

 roots, and leaves of the seedling during the process of growth. It is 

 evident further that approximately the same amounts of this mineral 

 matter go to stem and roots, respectively, whereas a somewhat larger 

 amount of the mineral matter migrates to the leaves of the seedhngs. 

 The fact that a relatively large amount of the mineral matter, amounting 

 in this case to something over one-third of the whole, remains in the 

 exhausted cotyledon is of interest and doubtless has the same signifi- 

 cance for the growth of the seedling as is believed to obtain in the case 

 of the bean, already discussed. The percentage distribution of the min- 

 eral constituents of corn during the growth of the seedling is shown in 

 Table IV. 



