INFLUENCE OF BORDEAUX MIXTURE ON THE RATES 
OF TRANSPIRATION FROM ABSCISED LEAVES AND 
FROM POTTED PLANTS 
By William H. Martin, 1 
Assistant in the Department of Plant Pathology, New Jersey Agricultural Experiment 
Station 
INTRODUCTION 
Since the introduction of Bordeaux mixture much work has been 
done on the effects which this fungicide has on the growth of normal 
plants. For more than 20 years this work has occupied the attention 
of pathologists. During this time progress has been made, but there 
still remains much to be done. Many observations have been made as 
to the effect which an application of this spray has upon transpiration 
rates, and a review of the literature brings out the fact that the conclu¬ 
sions drawn from these observations are conflicting. 
Rumm (15) 2 found that when abscised leaves were placed in water 
the unsprayed ones wilted first; from this he concluded that there is a 
decrease in the rate of transpiration following an application of the spray. 
Clinton (4) expressed the view that the water pores and stomata of potato 
leaves are clogged by the spray and as a result transpiration is decreased. 
Schander (16), Bayer (2), and Miiller-Thurgau (14) each expressed the 
opinion that decreased transpiration rates follow spraying with Bordeaux 
mixture. 
As a result of extensive investigations, Frank and Kruger (8, 9) con¬ 
clude that the water loss from sprayed plants is greater than from plants 
not so treated. Bain (1) likewise found that an increased rate of trans¬ 
piration occurs in peach seedlings as a result of spraying. He arrived at 
this conclusion from the fact that he found it necessary to supply water 
more frequently to the roots of seedlings that had been sprayed. More 
recently, however, Duggar and Cooley (6, 7) have furnished direct evi¬ 
dence bearing upon this question. In a series of very carefully per¬ 
formed experiments they have demonstrated that not only does a film 
of Bordeaux mixture on the leaves of castor beans, tomatoes, and potatoes 
increase their rates of transpiration but that other surface films have a 
similar effect. They have brought out the fact that certain specific 
qualities of the films applied are definitely related to the phenomenon of 
increased transpiration. They further state that the color of the film 
applied is also a factor to be considered in this connection. 
1 Thanks are due to Dr. M. T. Cook for suggesting the problem and to Dr. J. W. Shive for valuable sug¬ 
gestions during the progress of the work and for aid and criticism in the preparation of the manuscript. 
% Reference is made by number to “ Literature cited,” p. 547-548. 
Journal of Agricultural Research, Vol. VII, No. 12 
Department of Agriculture, Washington, D, C. Dec. 18,1916 
gn N.J.—4 
( 529 ) 
