F. W. WENT 



167 



with control by a set of different factors with different temperature rela- 

 tionships. This is particularly clear since the same linear relationship holds 

 between node formation and light intensity (fig. 5), or length of photo- 



IZO-i 



lOO- 



80- 



60- 



40- 



20- 





Temp °C 



— r- 



10 



— I— 



15 



— I — 

 20 



— r- 

 25 



— 1 — 

 30 



— 1 

 35 



Fig. 3. Relationship between temperature and rate of protoplasmic streaming in 

 Cham jnetida From Hille Ris Lambers 1926. 



S 04 



X) 



•- 03 

 o ( 

 a> 



S 0.2 



<u 

 tr> 



o 0.1 

 <i> 



k. 

 o 



■s 



Fig. 



Phototemp. 20° 

 Photoperiod I2hrs. 



10° 14° 17° 20° 23° 26° 

 Nyctotemperature 



Fig. 4. Rate of node forma- 

 tion in stem tips of Alaska peas 

 as a fimction of the nyctotem- 

 perature From Went 1957. 



300 700 I400ft.-c. 



Light intensity 



Fig. 5. Rate of node forma- 

 tion in stem tips of Alaska peas 

 as a function of the light inten- 

 sity under which tliey are grown 

 From Went 1957. 



period. Therefore we will have to find some basic process which is not in- 

 fluenced like a chemical I'eaction by temperature. 



AVhen tomato or other plants are grown in continuous light and con- 

 stant temperature, their growth is soon reduced and in the case of the to- 

 mato curious injury symptoms appear partly in the form of bleached leaf 

 areas and jiartly by necrotic spots on the young developing leaves (7). At 



