INOEGANIC CONSTITUENTS. 15 



potash, not merely because it is at their command, but because they 

 need the potash right then and there for the proper exercise of their 

 physiological functions. 



Kegarding the increase in the weight of the plants, the table shows 

 that the addition of any one salt produces an increased growth of 

 from 12 to 14 per cent in dry weight in nitrate solution; of from 4 to 

 11 per cent in the phosphate solution; and of from 14 to 15 per cent 

 in the potash solution. Although the seedlings take up a much 

 larger amount of potash than of nitrogen and phosphate, it has been 

 noted that the plants growing in the potash solution are inferior in 

 color and in luxuriance to those grown in the other two solutions. The 

 plants grown in the nitrate solution look the hardiest, having the 

 best color and apparently the most green matter, while those in the 

 phosphate solution are intermediate. No great difference was noted 

 between the dry weight of 100 plants 12 days old, as grown in the 

 three different culture solutions. 



RELATIVE AMOUNTS OF PLANT FOOD IN PLUMULE AND RADICLE WHEN 

 GROWN IN COMPLETE NUTRIENT SOLUTION. 



One experiment was conducted in order to determine the relative 

 amounts of nitrogen, phosphoric acid, and potash absorbed by the 

 radicle and translocated to, and accumulated in, the plumule, and 

 the amounts remaining in the radicle itself at different stages of 

 growth. This experiment was carried on both in a complete nutrient 

 solution and in distilled water, the latter serving as the control. The 

 weather being rather warm, the seedlings were grown in the control 

 solution for only seven days, having at the end of this period attained 

 about the size of seedlings twice that age when grown at a lower 

 temperature. The seedlings in the nutritive solution, however, 

 although grown at the same temperature, were allowed to develop 

 for 15 days. In order to determine the amounts of salts translocated 

 from the seed into the plumule and radicle, respectively, several 

 hundred axes v/ere separated from the seed and then further divided 

 into the radicle and plumule. The results obtained are shown in the 

 table following; all nitrogen determinations were made by T. C. 

 Trescot. 



