Oct. IS, 1919 Relation of Nutrient Medium to Plant A bsorption 



97 



Table IX. — Absorption from solutions of various concentrations and reactions in a 

 '/2-hour period by plants j weeks old 



WATER CULTURES, SERIES 4 



COMPOSITION (in parts PER MILLION OF ORIGINAL SOLUTIONS) 



ABSORPTION (iN PARTS PER MILLION OF SOLUTION) 



NUMBER OP GRAMS ABSORBED PER PLANT) 



PERCENTAGE OP ABSORPTION 



In the solutions of 0.07 atmospheres concentration, it is significant 

 that all the NO3 ions and nearly all the K and PO^ ions were absorbed 

 within 72 hours. It is not possible to say from these data just how the 

 absorption was distributed over the period of time in question, but it is 

 logical to suppose that the total quantities absorbed per hour decreased 

 until finally in the NO3 ion every trace had disappeared from the solution. 



The air-dry yields are given in Table X. Plants from each jar were 

 weighed separately in order to gain some idea of the mean deviation and 

 thus provide a basis for judging the significance of the results. 



