AMERICAN 
JOURNAL OF BOTANY 
Vol. IX December, 1922 ( ^ No. 10 
THE EFFECT OF BORDEAUX MIXTURE UPON THE 
CHLOROPHYLL CONTENT OF THE PRIMOR- 
DIAL LEAVES OF THE COMMON BEAN, 
PHASEOLUS VULGARIS L. 
W. A. Ruth 
(Received for publication March 4, 1922) 
Introduction 
To the quantitative relations and specific function of chlorophyll is to 
be attributed the faculty of the plant to produce much or little organic 
material under the prevailing conditions. Our knowledge does not enable 
us to make a final statement concerning the difference in chlorophyll in 
different individuals or species, but the results of recent and earlier investi- 
gations would lead us to the belief that the difTerence in performance, that 
is, in the ability to produce organic matter, rests largely, if not entirely, 
with the protoplast and depends upon the quantity, rather than the quality, 
of chlorophyll. 
Until Willstatter and Stoll (1913) published a method of analysis, the 
absolute quantity of chlorophyll per unit area of leaf tissue could not be 
determined. Thus, Rose (1913, p. 29) compared leaf extracts with a 
standard extract of unknown value. 
La chlorophylle n'ayant pas ete isolee, on ne pent, comme le fait observer Lubimenko, 
proceder a des determinations de quantites absolues. II faut se contenter de la determi- 
nation de quantites relatives a un etalon. 
A plan for a systematic quantitative study of the chlorophyll content 
of foliage leaves is part of a general project of the laboratory of plant 
physiology of the University of Illinois. This paper is limited, for the most 
part, to a study of the efTects of Bordeaux mixture; other relations were 
studied more or less incidentally, these consisting of the relation of the 
amount of chlorophyll to the age of the leaves and to the rapidity of their 
growth. 
The studies are to be prosecuted along two general lines: First, a study 
of the quantitative relation of the chlorophyll content of plants treated in 
various ways but growing under the general external conditions which 
[The Journal for November (9 : 471-533) was issued November 27, 1922]. 
535 
