-56- 



Teinperature Coeff iolents for ghoot Elongation . 

 ■fTobably the^most satisfactory method for 

 characterizing the temperature relations of anjr process is 

 that employing temperature coeff icients« f 10 } The temperature 

 coefficient for a given process and for a given temperature 

 interval is the quotient obtained by dividing the rate for the 

 higher temperature by that for the lower. The Interval is 

 conveniently taken as lO^c.and the symbol for the coefficient 

 is generally expressed as o7l(\. The values for Q/1'3\ were 

 obtained fo^ shoot elongation in these seedlings for the entire 

 period, for all the 10-degree intervals available. The upper 

 graph of figure 1 was used for determinng the approximate 

 hourly rate for each temperature from 13 pl'^o 35°C. The rate 

 for 13° is ,S9mm. and that for 2Z° is 1.30 mm., so that tfee- 

 c/lA (13°-23°) is, 1.30 divided .29, which is 4.5. The values 

 of ^ /ld\ obtained for all the 10-degree ranges are presented 

 in table VIII which is self-explanatory. 



(10) "cor roferenooo - to -%he- literattire on this 

 subject see the following, and the references there given: 

 Livingston, B.E. and Livingston, G.J, Temperature coefficients 

 in plant geography and climatology. Bot.daz. 56:349-375.1913. 



Lehenbauer,P.A. Growth of maize seedlings in relation 

 to temperature, Physiol. 'Res. 1:347-286.1914. 



Eanitz.Aristides, Temperatur und Lpbensvorgjlnge. 

 Heft 1:3-175. Berlin. 1915. 



Fawcett,H,S. The temperattire relations of growth 

 in certain parasitic fungi. Univ. Calif .Piib.Agri. Sci.4 :183-232. 



1921;.' 



