THE CHLORID CONTENT OF THE LEAF TISSUE FLUIDS 
OF EGYPTIAN AND UPLAND COTTON 1 
By J. Arthur Harris, 8 Collaborator , Bureau of Plant Industry , John V. 
Lawrence, formerly Field Assistant t Office of Western Irrigation Agriculture , 
and Zonja Wallen Lawrence, formerly Field Assistant , Offices of Alkali and 
Drought Resistant Plant Investigations and Office of Biophysical Investigations , 
United Stales Department of Agriculture 
INTRODUCTION 
In earlier investigations of the physico-chemical properties of the leaf tissue 
fluids of Pima Egyptian and Acala and Meade Upland cotton (5) 3 we have shown 
that when grown under irrigation at the United States field station in the Gila 
River Valley at Sacaton, Ariz., the Egyptian cotton is characterized by higher 
osmotic concentration, as measured in terms of freezing point depression, A, and 
higher specific electrical conductivity, k, of its tissue fluids than either of the 
two Upland varieties. 
The consistently higher osmotic concentration of the tissue fluids of the Egyptian 
cotton might be due to either greater capacity for the synthesis of organic solutes 
or to greater capacity for the absorption and for the retention in solution of 
electrolytes from the soil. The higher constants for the specific electrical 
conductivity, k, of the tissue fluids of the Egyptian cotton point to the absorp¬ 
tion and tolerance in solution of electrolytes as important factors in the differen¬ 
tiation of the physico-chemical properties of the tissue fluids of the two types 
of cotton. 
In analyzing the physiological differences between the Egyptian and Upland 
types more minutely, therefore, it becomes of importance to determine the con¬ 
centration of specific solutes in the tissue fluids. 4 
The desirability of an investigation of the chlorid content of the tissue fluids 
of the Egyptian and Upland types of cotton is suggested by the early observations 
of Kearney and Means (7) and of Kearney ( 6 ) on the growth of cotton in saline 
soils. Furthermore, Balls (I, 2) has called attention to the relatively high 
chlorid content of cotton plants grown in Egj^pt. 
In view of these observations, and of the differences in the physico-chemical 
properties of the tissue fluid of Pima Egyptian, Meade, and Acala Upland 
cotton already distinguished (5), the determination of the concentration of 
chlorids in the tissue fluids of different varieties might seem to be of particular 
importance in selecting crop plants which may best be grown in regions of so-called 
alkali soils, in many of which the content of chlorids is very high. 
1 Received for publication February 16, 1924. 
investigator, Station for Experimental Evolution, Cold Spring Harbor, New York. 
* Reference is made by number (italic) to “Literature cited,” p. 704. 
4 This has been one of the primary purposes of this phase of the work carried out on cotton by the Office 
of Alkali and Drought Resistant Plant Investigations, the Office of Biophysical Investigations, and the 
Office of Western Irrigation Agriculture, of the Bureau of Plant Industry, United States Department of 
Agriculture, since 1921. For the opportunity of joining in this program we are indebted to T. H. Kearney, 
Q. N. Collins, and C. S. Scofield, in charge of the three offices mentioned. 
Journal of Agricultural Research, 
Washington, D. C. 
( 695 ) 
Vol. XXVIII, No. 7 
May 17,1924 
Key No. G-418 
