648 
Journal of Agricultural Research 
Vol. V, No. 14 
Least-square reductions of the dependence of transpiration upon 
radiation and air temperature or upon radiation and saturation deficit 
do not account entirely for the observed transpiration, although a satis¬ 
factory agreement between computed and observed evaporation is 
obtained by the use of these environmental factors. This indicates that 
the plant undergoes changes during the day which modify its transpira¬ 
tion coefficient. In other words, our results support the conclusion of 
other investigators that plants under conditions favoring high evapora¬ 
tion do not respond wholly as free evaporating systems, even if bounti¬ 
fully supplied with water and no visible wilting occurs. 
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thisar- 
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