20 



TEAXSLOCATIOX OP PLAXT POOD IN WHEAT SEEDLINGS. 



about 60 per cent. The per cent of fat in the axes, based on the 

 amount present in the original seed, is shown in the folloT^TLiig table: 



Table 5. — Relative amounts of fat in the axes ichen groivn in varying nutrient solutions 

 (based on original amount in seed). 



Age of 

 plant. 



Control 

 solution. 



Potash 

 solution. 



Phosphor- 

 ic solu- 

 tion. 



Control. 



Nitrate 

 solution. 



Complete 

 solution. 



Days. 

 5 



9 

 12 

 15 



Percent. 

 34 

 51 

 70 

 73 

 70 



Percent. 

 31 

 52 

 60 

 73 



Percent. 

 34 

 66 



87 

 85 

 91 



Percent. 

 34 



48 

 65 



Per cent. 

 30 

 64 

 89 



Per cent. 

 52 



61 

 86 

 98 

 103 



66 



94 



At five days practically the same amount of ether-extract substance 

 is found in the axes of the seedlings grown in the nitrate, potash, and 

 phosphoric acid solutions as in the control. Those grown m the 

 complete solution, however, contain considerably more fat than the 

 others, the reason for which is that plants gro^Ti m the complete 

 medium are about as large at 5 days as those gro^m m the other 

 solutions are in 7 days. At the end of 15 days it is seen that the 

 axes of seedlings grown in the control solution contain about 70 per 

 cent of the amount of fat present in the original seed, while those of 

 the potash solution contain 79 per cent, those of the phosphate solu- 

 tion 91 per cent, of the nitrate solution 9-i per cent, and of the com- 

 plete solution 103 per cent. It is thus seen that more substances 

 soluble in ether are formed in the same length of time under the influ- 

 ence of nitrates and phosphates than under that of potash. This is 

 to some extent due to the greater amount of chlorophyll bodies found 

 in the first two instances; the plants groTMi in the potash solution 

 were never so green nor so luxuriant as those in the nitrate, the 

 phosphate, or complete solution. 



From Table 6 it is seen that, based on the dry weight of the seed- 

 lings, the per cent of fat found in the axes of the plants grown in the 

 various solutions at the end of 15 days is as follows: In the controls, 3 

 and 3.2; in the potash solution, 3.1; in phosphate, 3.6; in nitrate, 3.7; 

 and m complete solution, 3.7. Thus, while the nonembryonic fat to 

 the extent of 60 to 67 per cent of the original amount remains con- 

 stant and unabsorbed in the seed, the axes, beginnmg with from 30 to 

 35 per cent of embryonic fat (based on the amount in the original 

 seed), have, at the end of 15 days, increased this amount to from 70 

 to 103 per cent, this extra amount being formed by the process of 

 assimilation. The largest amount was elaborated by the seedhng 

 grown in nitrate and in phosphate solutions, which salts seem to 

 stimulate the production of ether-soluble substances to some extent. 

 Mention has already been made of the fact that the plants grown in 



