1222 



THE TEMPERATURE FACTOR 



CHAP. 31 



(c/. fig. 31.4). Craig and Trelease (1937) found no marked time effect in 

 Chlorella up to 46° C, if the exposure was restricted to 20 minutes. 



150 min 



10 15 20 25 30 35 40 45 

 TEMPERATURE, "C. 



Fig. 31.3. Temperature curves of photo- 

 synthesis of cherry laurel (Jost 1906, after 

 Blackman and Matthaei 1905). 



*-• 5 10 15 20 25 30 35 

 TEMPERATURE, "C. 



Fig. 31.4. Temperature curve of 

 photosynthesis in Chlorella (after 

 Noddack and Kopp 1940). 



25? 



20 



u 



n . 



E 

 £ 



15 



o 10 



lO . 



e 



E 



o 

 o 



o 

 o 



o 

 8 



*-" 10 20 30 40 



HEAT TREATMENT, min. 



Fig. 31.5. Effect of heat treatment (at 45° C.) on photo- 

 synthesis of Chlorella (after Kennedy 1940). 



The use of rapid recording devices (cf. chapter 25) may permit follow- 

 ing the ascending temperature curve of photosynthesis beyond the range 

 attained by Blackman and Noddack. 



