VOLUME XLIX NUMBER 2 
BOTANICAL GAZETG 
FEBRUARY 1910 
THE EFFECT OF CERTAIN CHEMICAL AGENTS UPON 
THE TRANSPIRATION AND GROWTH 
OF WHEAT SEEDLINGS 
HOWARD S. REED 
(WITH NINE FIGURES) 
The physiological factors involved in transpiration present nu- 
merous opportunities for critical study. A vast number of researches 
" upon these factors have been made and our knowledge has been 
increased thereby; nevertheless the results of some important pieces 
of work are contradicted by others and more data seem to be neces- 
sary to elucidate certain questions. 
The present paper is intended to set forth some data upon the effect 
of certain chemical compounds (mostly salts) upon the transpiration 
of wheat plants in relation to the effect of the same compounds upon 
the growth of the plants. ‘In other words, the paper is in part a 
study of the effect of these compounds upon the units of water trans- 
pired for unit of plant substance produced. 
The general literature bearing upon the effect of chemicals upon 
transpiration has been so well brought together and summarized 
by BURGERSTEIN (2) that a general review of literature need not be 
given at this place. A few studies which have especial bearing upon 
the present work, however, will be mentioned. 
LAwEs (6) made a careful investigation of the amount of water 
required by several plants grown to maturity, where possible, in 
sealed pots of soil. He used in one series soil to which no application 
of fertilizing compounds was added; in the second series a mineral 
fertilizer consisting of potassium sulfate, magnesium sulfate, so- 
dium chlorid, and mono-calcium phosphate was added to the soil; 
in the third series the mineral fertilizer used in the second series was 
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