PLANT RESPONSE 



67 



compared with responses given at the same temperatures 

 while warming (see table). Temperature variation thus 

 seems to have a stimulating effect on response, by 

 increasing molecular mobility in some way. The second 



FIG. 40. KECORDS OF KESPONSES IN EUCHARIS LILY DURING KISE AND 

 FALL OF TEMPERATURE 



Stimulus constant, applied at intervals of one minute. The temperature of 

 plant-chamber gradually rose on starting current in the heating coil ; on 

 breaking current, the temperature fell gradually. Temperature correspond- 

 ing to each record is given below. 



Temperature rising: (1) 20, (2) 20, (3) 22, (4) 38, (5) 53, (6) 68, (7) 65. 

 Temperature falling : (8) 60, (9) 51, (10) 45, (11) 40, (12) 38. 



record (fig. 40) shows the variation of response in 

 Eucharis lily (1) during the rise, and (2) during the fall 



TABLE SHOWING THE VARIATION OF RESPONSE IN SCOTCH KALE 

 DURING THE RlSE AND FALL OF TEMPERATURE 



Temperature Kesponse 



[Temperature rising] 



19 C. ...... 47 dns. . . 



25 ... ... 24 



30 . . 



50 . . 

 70 



. Eesponse 

 [Temperature falling] 



11 ....... 28 dns. 



8 ....... 16 ,. 



7 



F 2 



