THE LEAF-TISSUE FLUIDS OF EGYPTIAN COTTONS 1 
By J. Arthur Harris, Head, Department of Botany, University of Minnesota y 
and Collaborator, Bureau of Plant Industry, United States Department of-Agri¬ 
culture; W. F. Hoffman, Assistant Professor of Agricultural Biochemistry, 
University of Minnesota, formerly (1920-192Jf) Field Assistant, Alkali and 
Drought Resistant Plant Investigations, and Biophysical Investigations, Bureau 
of Plant Industry, Uni ed States Department of Agriculture; W. B. Sinclair, 
Assistant in Agricultural Biochemistry, University of Minnesota, formerly 
(1923—24) Field Assistant, Alkali and Drought Resistant Plant Investigations, 
<md Biophysical Investigations, Bureau of Plant Industry, United States Depart¬ 
ment of Agriculture; A. H. Johnson, Assistant Professor of Agricultural Bio¬ 
chemistry, University of Minnesota, formerly (1922) Field Assistant, Alkali and 
Drought Resistant Plant Investigations, and Biophysical Investigations, Bureau 
of Plant Industry, United States Department of Agriculture; and R. D. Evans, 
Instructor in Bacteriology, University of Minnesota, formerly (1922) Field 
Assistant, Alkali and Drought Resistant Plant Investigations, and Biophysical 
Investigations, Bureau of Plant Industry, United States Department of Agriculture 
INTRODUCTION 
In 1921 a series of determinations of the physicochemical properties 
of the leaf-tissue fluids of Egyptian and Upland cottons and of their 
Ei hybrid (3 ) 2 showed that, when grown under irrigation at Sacaton, 
in the Gila River Valley of southern Arizona, the leaf-tissue fluids of 
Pima Egyptian cotton are characterized by higher osmotic concentra¬ 
tion, higher specific electrical conductivity, and higher hydrogen- 
ion concentration than those of Meade or Acala Upland cotton (3 ). 
In subsequent studies it has been shown that the differentiation is 
also clearly marked in chloride (If) and in sulphate (7) content, and 
that the absorption of these two ions is differential (5), 
The question will naturally arise, however, as to whether the sap 
properties found for Pima may be considered wholly typical of the 
Egyptian type in this regard. Kearney has shown (8, 9 , 10, 11) 
that the Pima variety has a long history as an American-grown 
cotton. It seems quite possible that the differences between its 
tissue-fluid properties and those of the upland varieties with which 
it was compared may have arisen during this period in America. 
The plausibility of this suggestion is emphasized by Balls 7 ( 1) 
conclusion that in Egypt the different strains of cotton differ in the 
salinity of their tissue fluids. 
One purpose of the present investigation has been to determine 
whether varieties of Egyptian cotton other than Pima differ from 
Acala, Meade, and Lone Star Upland cotton in their tissue-fluid 
properties, or whether this difference is characteristic only of the 
American Egyptian variety, Pima. 
MATERIALS AND METHODS 
In 1922 plantings of seeds of five Egyptian varieties imported in that 
year from Egypt were made for comparison with Pima Egyptian and 
Meade upland cotton from American-grown seed. In 1924 the new 
1 Received for publication May 28, 1925; issued January, 1926. 
2 Reference is made by number (italic) to “Literature cited,” p. 1033. 
Journal of Agricultural Research, 
Washington, D. C. 
( 1027 ) 
Vol. XXXI, No. 11 
Dec. 1, 1925 
Key No. G-451 
