THE REQUIREMENTS OF PLANTS 



21 



Temperature 



Amount of CO^ assimilated per hour 

 Increased rate for io° C. . 



o" 

 175 



10" 

 2-4 



20° 

 89 



2-1 , 



30 



157 

 1-8 



37° 

 238 

 1-8 



But, on the other hand, the effect of temperature on the rate of 

 growth of a plant is in no wise Hke its effect in accelerating chemical 

 change. Bialoblocki's (37) results with barley were as follows : — 



The two curves are shown in Fig. i ; the difference between them is 



r 





c eo 



I *^ 

 T 





w 



0° 



•¥J0° -¥20° +30° +40° +50° 

 — »- Temperature. 



Fig. ia. — Relation between Temperature and Assimilation. (Miss Matthaei.) 



,| -JO' 0° +10" +Z0° +30° +40° +50' 



— *- TeiKperabwrs. 



Fig. IB.— Relation between Temperature and Plant Growth. (Bialoblocki.) 



of fundamental importance to our subject and must be discussed in 

 some detail. 



Each of the separate processes — assimilation, respiration, etc. — 

 gives, so far as is known, curves like Fig. la continuous over the whole 



