458 
Journal of Agricultural Research 
Vol. V, No. it 
The relatively high percentage of ash in the sprout of the potato as 
compared with that contained in the exhausted tuber is a matter of 
interest. It will be seen, however, that considerable amounts of ash 
still remain in the exhausted tuber after the growth of the sprouts is 
complete, indicating the necessity of mineral matter for those changes 
occurring in the tuber during the act of sprouting. Table VI gives the 
percentage distribution of the several mineral constituents between the 
sprouts and exhausted tubers, including the skin. 
Table VI .—Percentage distribution of the mineral constituents of potatoes 
Part. 
Phosphorus 
as PaOs. 
Calcium 
oxid (CaO). 
Magnesium 
oxid (MgO). 
Potassium 
as KsO. 
Silica 
(SiOj). 
Sprouts. 
Tubers (exhausted). 
* 7 - 77 
13. 12 
13.84 
12. 68 
5 * *3 
67.13 
42. 02 
6 S .68 
64*43 
12. 41 
In Table VI it is observed that a large amount of the mineral material 
remains unused in the exhausted tuber of the potato and that approxi¬ 
mately only 15 per cent of the different mineral constituents have mi¬ 
grated to the sprouts. 
CONCLUSIONS 
The most striking fact brought out thus far by these studies on the 
translocation of the mineral matter of the seed and tuber during the 
growth of the seedling is the retention of considerable amounts of the 
mineral matter, varying from 46.66 per cent in the garden bean and 
38.66 per cent in com to 50.33 per cent in the potato tuber in the cotyle¬ 
dons and tuber, respectively. As indicated in the foregoing experi¬ 
ments, this probably finds its explanation in the necessity for definite 
amounts of the various mineral constituents to promote the katabolic 
changes occurring in the cotyledon and tuber during sprouting. So far 
as could be ascertained, there were no very striking differences in the 
quantities of its several mineral constituents translocated and no marked 
selective influences shown by the roots, stem, and leaves of the growing 
seedling for any particular mineral reserve material contained in the seed 
or tuber. Up to the present time, great difficulty has been experienced 
in the selection of a suitable container in which to grow these seedlings. 
This has proved a serious obstacle to this work. It is hoped, however, 
that this difficulty may be finally overcome and better and more con¬ 
stant results obtained through the use of pure paraffin containers. 
