June, 1922] MUENSCHER — ABSORPTION OF SALTS 315 



General Outline of Experiments 



The experiments which are reported in this paper were undertaken in 

 order to obtain data which might indicate whether or not there is any rela- 

 tion between absorption of water and of mineral nutrients. The absorp-' 

 tion of water was determined by measuring volumetrically the amount of 

 water lost from the containers. The absorption of salts was determined 

 by analyzing the plants for total ash. It is realized that the measure of 

 ash does not represent an actual measurement of salts absorbed. However, 

 with a uniform solution and a uniform method of analysis, for a given 

 species the results are comparable as far as relative values are concerned. 

 Two series of experiments, summer and winter, were conducted in the 

 greenhouse. In the summer series the rate of transpiration was reduced 

 by increasing atmospheric humidity and by decreasing the intensity of sun- 

 light. In the winter series transpiration was reduced by decreasing the 

 light intensity and also by increasing the concentration of the nutrient solu- 

 tion. Cultures were grown under the following conditions: 



I. Summer Series 



a. Dry chamber; standard Knop's solution^ (.14%). 



b. Humid chamber; standard Kpop's solution (.14%). 



c. Sunlight; standard Kijop's solution (.14%). 



d. Shade tent; standard Knop's solution (.14%). 



II. Winter Series 



e. Sunlight; dilute Knop's solution (.07%). 

 /. Shade tent; dilute Knop's solution (.07%). 



g. Sunlight; concentrated Knop's solution (.28%). 



Materials and Methods Used 

 Summer Series 



The chambers used for the dry and humid series of cultures consisted of 

 large glass cases each 140 centimeters long, 70 centimeters wide, and no 

 centimeters high, placed in the middle of a greenhouse room. The air 

 was kept in circulation continuously during the daytime by a fan in each 

 chamber. Fresh air was pumped into the chambers by a compressor which 

 was attached to a motor outside the chamber. 



The atmospheric humidity in the humid chamber was kept high by a 

 "^^The following standard Knop's solution was employed as the basis for making up the 

 nutrient solutions: 



Ca(N03)2 0.8 gram 



KNO3 0.2 gram 



KHjPO* 0.2 gram 



MgS04 j 0.2 gram 



FePOi trace 



Distilled water. 1,000 cc. 



Total 1.4 grams 



