THE TISSUE FLUIDS OF EGYPTIAN AND UPLAND 
COTTONS AND THEIR F, HYBRID 1 
By J. Arthur Harris, Investigator, Station for Experimental Evolution, Cold Spring 
Harbor , Collaborator, Bureau of Plant Industry, United States Department of Agri¬ 
culture; Zonja Wallen Lawrence, Associate in Chemistry, University of Chicago , 
Field Assistant, Bureau of Plant Industry, United States Department of Agriculture, 
iQ2i; W. F. Hoffman, Instructor in Agricultural Biochemistry, University of Minne¬ 
sota, Field Assistant, Bureau of Plant Industry, United States Department of Agri¬ 
culture; John V. Lawrence, Associate Professor of Pharmacology, University of 
• Cincinnati, Field Assistant, Bureau of Plant Industry, United States Department of 
Agriculture, 1921; A. T. Valentine, Field Assistant, Bureau of Plant Industry, 
United States Department of Agriculture, 1920-1921. 
INTRODUCTION 
This paper has a twofold purpose: (a) The presentation of the results 
of an investigation of the physicochemical properties of the leaf tissue 
fluids of Egyptian and Upland cotton as grown under irrigation at 
Sacaton, Ariz.; ( b ) a comparison of the properties of the leaf tissue fluids 
of the Fj hybrid between these two cottons with those of the two parent 
types. 
The consideration of both of these groups of problems rests on the re¬ 
sults of much antecedent work. 
In a series of investigations carried out in natural plant habitats the 
writers have shown that there is a close relationship between the aridity 
of the habitat and the osmotic concentration of the plant tissue fluids of 
the native vegetation. These results, obtained by careful cryoscopic 
measurements in the southwestern deserts (jo) 2 , in the mesophytic 
habitats of the Eastern United States (29), in the Jamaican deserts ( 26 ) 
and rain forest (28), in the mangrove swamp (27), and in many other 
localities for which the data are not yet published, fully substantiate 
and greatly extend the general conclusions drawn from the earlier plas- 
molytic determinations by Drabble and Drabble ( 14 ) and by Fitting 
(75). That the osmotic concentration of the plant tissue fluids is a 
factor of importance in determining the capacity of the plant for survival 
under conditions of aridity is suggested by work on the relationship of 
the loranthaceous parasite to its host, as investigated by plasmolytic 
studies by Senn (48), and by cryoscopic studies on both rain forest and 
desert (20, 25, 33). 
Concurrently with these investigations on the osmotic concentration 
and electrical conductivity of plant tissue fluids, another group of workers, 
among whom Wherry has been the most active, has furthered investiga¬ 
tions on the relationship between soil acidity and plant distribution. 
In this place it will suffice to refer to the more recent reviews by Wherry 
(51) and by Atkins (2). 
From the earliest stages of the investigations we realized the desira¬ 
bility of investigations of the sap properties of agricultural plants. Since 
natural vegetations have been shown to differ in the physicochemical 
properties of their tissue fluids, it would seem quite reasonable to assume 
1 Received for publication June 21, 1923. 
2 Reference is made by numbers (italic) to “literature cited/’ p. 325-327. 
Journal of Agricultural Research, 
Washington, D. C. 
(267) 
Vol. XXVII, No. s 
Feb. 2, 1924 
Key No. G-360 
