SUMMARY 265 



The enhancement of activity under these conditions 

 may be calculated as follows : — 



from (a) to (b) — 

 Activity for C0 2 -concentration 5-0 _ 183 , , » 



Activity for C0 2 -concentration 3-0 no* 5 

 from (b) to (c) — 

 Increase of activity by doubling light from 



750 to 1500 lux =2-0 (2) 



Increase of activity due J:o variation of 

 temperature from 20 to 24 C. (physio- 

 logical zero at 9°*5 C.) found by the 



formula 24 ~ 9 ' 5 =1-38 (3) 



20-9-5 



As regards tonicity, since other factors had 

 already enhanced the activity, the further 

 increase is about 1 • 5 times = 1 • 5 (4) 



The resultant enhancement of activity is theoretically 

 the product of (1) X (2) X (3) X (4) X original activity: 

 hence the calculated result is 



= 1-65 X 2 X 1-38 x 1-5 X 110-5 = 754-8 c.mm. 



Observed result =748-2 ,, 



It therefore follows that : 



A 



CLTP 



is a constant. 



Summary 



It has been demonstrated that (1) when there is simul- 

 taneous variation of different factors in photosynthesis, 

 each factor contributes its full independent effect, and 

 (2) that the resultant effect of the simultaneous variation 

 of factors is, not the sum, but the product of the effects of 

 the individual factors. 



This is the Law of Product, which is expressed by the 



general formula which is a constant. 



""■ CLTP 



