Bouyoucos, Transpiration of Wheat Seedlings as Affected etc. 15 



Table VII. 



Density of Cell Sap of Bean Seedlings as Determined by the Electrical 



Resistance Method. 



P. p. m. of Solution Resistance of Cell Sap 



in Which Plants Grew in Ohms 



750 1479.6 



4500 1158.1 



These figures show most strikingly that the foreg'oing' relation 

 holds true also with beans. It will be noticed that the 4500 P. p. m. 

 Solution gave cell sap with 321.5 ohms more concentration than 

 the 750 P. p. m. Solution. 



Experiment IV. This experiment consisted of growing wheat 



N N 



seedlings for 15 days in Solutions of ^ and ^ ^ of CaCla to each 



one of which was added exactly the same amount of a complete 

 nutrient Solution in order that the plants may make a normal growth. 

 The object of this series was to see whether the density of the 

 cell sap of the plants grown in different densities of the non- 

 nutrient Solution, would run in the same order as that of the dif- 

 ferent concentration s of the complete nutrient Solution already noted. 

 The cell sap was extracted in this case, from 1.6330 grams of 

 green weight, diluted to 200 cc, and the density determined by 

 the electrical resistance method. Folio wing are the results obtained. 



Table VIII. 



Density of Cell. Sap of Wheat Seedlings as Determined by the Electrical 



Resistance Method. 



F. p. m. of Solution Resistance of Cell 



in Which Plants Grew Sap in Ohms 



250 



CaCla ^.^ 1007.2 



0a0l3 ^ 952.8 



It is evident that even with the non-nutrient salt Solutions, 



the concentratious of the cell sap decreased with the decline in 



density of the Solution. It will be apparent that in the case of the 



N 



-^TT Solution, the resistance of the cell sap is 54.4 ohms less than 



oO 



N 

 that of the -^r^^pr Solution. 

 2oO 



It seems then from all the preceding experiments, that the 

 assumption originally made, namely, that the density of the cell 

 sap may be proportional to the concentration of the Solution in 

 which the plants are growing, is correct, or at least the foregoing 

 data have confirmed it in every case without a Single exception. 



If it is true that there is a close relation between the den- 

 sity of the cell sap and that of the outside Solution, this would at 



