Journal of Agricultural Research 
Vol. XXVII, No. 12 
894 
consider the physical and chemical properties of the plant tissue 
fluids in the same way that they did the physical and chemical properties 
of the soil. 
Since their studies were completed, much progress has been made in 
the investigation of the properties of the plant tissue fluids in relation 
to environmental factors. The pioneer plasmolytic studies of Drabble 
and Drabble (4) in the little diversified English habitats and of Fitting 
(5) in the extreme conditions of the North African deserts have been 
followed by more exact measurements by the cryoscopic method carried 
out in the Arizona deserts (. 12 ), in costal deserts (75), in the man¬ 
grove swamps (j 6), in the mesophytic habitats of the eastern United 
States (jj), where electrical conductivity of the sap has also been in¬ 
vestigated (20), and in the Montane Rain Forest of Jamaica (17). The 
results of these studies, which have been reinforced in their significance 
by parallel investigations on the tissue fluids of epiphytic plants (18) 
and on those of parasite and host in the case of both rain-forest (jj) 
and desert Loranthaceae {19) point clearly to a close relationship between 
the physicochemical properties of the leaf tissue fluids of the plant and 
its geographic distribution. The significance of this relationship has 
been emphasized elsewhere (14). 3 
METHODS 
The methods employed are those used in a series of investigations 
published by the writers during the past several years. 
Tissues were collected in heavy-walled glass tubes and were thoroughly 
frozen in an ice-salt mixture for at least 10 hours (6) in order to render 
the tissues permeable as has been shown to be necessary by Dixon and 
Atkins (j) and by Gortner, Lawrence, and Harris (7). Sap was then 
extracted by pressure in a heavily tinned steel press bowl and was cen¬ 
trifuged before the determination of the constants. Freezing point 
lowering, A, was determined by means of a thermometer graduated to 
hundredths of degrees. 4 
Correction for the concentration caused by undercooling was made 
by the usual formula. The results are expressed in degrees of freezing 
point lowering, A, and in atmospheres pressure, P, as calculated from a 
well known formula (9), and tabled up to A = 5.99° (jo). 
Specific electrical conductivity was determined at 30° in a Freas 
conductivity cell standardized against N/10 KC 1 taken as having a 
specific electrical conductivity at 30° of 0.01412 mho. 
8 The possible bearing of such investigations on agriculture has been definitely in mind from the earliest 
stage of the work. A favorable opportunity for initiating studies of the properties of the tissue fluids in 
relation to agricultural problems presented itself in 1919 when Dr. T. H. Kearney, Physiologist, in charge of 
Alkali and Drought Resistant Plant Investigations, and Mr. G. N. Collins, Botanist, in charge of Biophy¬ 
sical Investigations, of the Bureau of Plant Industry, United States Department of Agriculture, suggested 
that it would be desirable to ascertain to what extent the physicochemical properties of the tissue 
fluid of the plants differ from association to association in response to the differences in soil conditions. 
As a result of this suggestion, work was undertaken in Tooele Valley in May, 1920. Grantsville was 
selected as a base because of the ready accessibility of all of the associations. The following pages give 
the results of determinations carried out in this region in May, June, and July. While a certain number 
of supplementary observations were made in the Stansbury Mountains, in Rush Valley and in the Sevier 
Desert to the south, the results presented here are mainly restricted to the plant associations treated by 
Kearney, Briggs, Shantz, McUane, and Piemeisel. 
Since our primary object in this investigation was to reinvestigate from an entirely new side the prob¬ 
lem considered by our predecessors in the field, we have made every effort to follow as exactly as possible 
the classification of vegetation adopted by them. The present paper is therefore incomplete except as it 
is considered in connection with the survey already cited. For this reason a detailed description of habi¬ 
tats and of the general features of the vegetation is superfluous. 
It is a pleasure to acknowledge our great obligation to Ivar Tidestrom of the Office of Economic and 
Systematic Botany, Bureau of Plant Industry, United States Department of Agriculture, for his pains¬ 
taking work in the identification of our herbarium materials. 
4 In the case of some of the more concentrated saps a thermometer of +1 to — 10 degrees range graduated 
ni one-fiftieth degree was of necessity used instead of the one graduated in one-hundredth degree units. 
