14 Bouyoucos, Transpiration of Wheat Seedlings as Afifected etc. 



Table IV. 



Density of Cell Sap as Determined by the Freezing Point Method. 



P. )). in. ot Solution Freezing point 



in wliicli l'lants Grew of the Cell Sap. 



0.0 4.200» C 



93.5 4.190» C 



4500.0 4.175» 



Table V. 



Density of Cell Sap as Determined by tbe Electrical Resistance Method. 



P. p. m. of Solution Resistance of Cell 



in which Plants Grew Sap in Ohms 



93.5 592.5 



4500.0 411.9 



It is evident froiii both tables that the density of the cell 

 sap diminished with the decrease in density of the Solution. It 

 will be Seen that in the first table the cell sap of the plants grown 

 in the highest density of Solution lowered the freezing point 

 .0150 C niore than that in the lower concentration, and .025 « C 

 niore than that in the check. In the second table, tlie electrical 

 resistance was 180.6 ohms less in the plant jnice derived from the 

 plants grown in the highest concentrated Solution than in the other. 



Experiment IL This experinient w^as the sanie as the pre- 

 ceding one except that in this case only the electrical resistance 

 method was used to measure the density of the cell sap. The 

 results obtained are given in the following table. 



Table VI. 



Density of Cell Sap as Determined by the Electrical Resistance Method. 



P. p. m. of Solution Resistance of Cell 



in Which Plants Grew Sap in Ohms 



93.5 422.0 



4500.0 210.9 



It will be observed that as in the foregoing experiment the 

 density of the cell sap was decreased with the reduction in con- 

 centration of the Solution. 



These experiments were repeated also in sand cultures, and 

 the data obtained were identical as the above. 



Experiment III. In this experiment beans were used instead 

 of wheat, the object being to see whether the above relation would 

 hold true with other species. These plants were allowed to grow 

 for 45 days in complete nutrient Solutions of 4500 and 750 P. p. m. 

 Exactly 5.6900 grams of green weight were taken, the cell sap 

 extracted as usual, diluted to 500 cc, and the density determined 

 by the electrical resistance method. The table l)elow contains the 

 results secured in this case. 



